Author Topic: New project 1937 aero 600  (Read 4892 times)

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Offline Tazmantic

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New project 1937 aero 600
« on: 01 Apr 2023 at 18:42 »
Hi all,

Been a while been busy on other projects but today picked up an Aero 600 cosmetically it looks good but mechanically needs quite some work Iím just finding out. My first question (of no doubt many) is gearbox itís the correct one I believe (U/***) and matches the register but I can only seem to find 3 gears should it not have 4? And is 1st fully forward (like my 250) or fully back.

Many thanks
« Last Edit: 05 Apr 2023 at 19:08 by Tazmantic »

Offline Dads bike

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Re: New project 1937 aero 600
« Reply #1 on: 01 Apr 2023 at 20:47 »
Evening
Yes the U prefix gear box is for a 1937 Aero and it is a four speed box. Note that from 1937 on, the gear box was oil filled not grease. Oil required was Castrol D 140, still available.
The gear leaver gate on the tank; fully back (up) is first gear, the next notch going down in the gate is neutral.
Make sure that the rack and pinion on the selector within the box are aligned correctly ie the centre dots on both the rack and pinion are aligned otherwise you wonít be able to select all the gears.
The engine and frame numbers should both be P prefix.

Steve

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #2 on: 01 Apr 2023 at 21:15 »
 Hi Steve,

Thanks for the reply, I did think looking on the internet that the 2nd notch should be neutral but on mine the top notch is a gear, so is the next notch down (should be neutral)!then the long gate is all neutral then fully forward is a gear so I presume I just need to take the cover off to line it all up? And yes both frame and engine are P though the engine has been changed as the mounting lugs had corroded off the original engine but the previous owner has got the v5 changed. Next question will be clutch as thatís just slipping.

Cheers Neil

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #3 on: 03 Apr 2023 at 20:28 »
So took cover off today and sure enough there was a line on the rack but could not find a line or dot on the pinion, I played about and have found 4 gears I think though some gears need going past the gate to engage/disengage so hoping I can adjust that out or maybe Iíve the pinion a tooth out is there an easy way to set this if there is no mark? Iím presuming take the box off and set it via the selector and indent plunger position.

Neil

Offline Doug

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Re: New project 1937 aero 600
« Reply #4 on: 04 Apr 2023 at 02:04 »
The mark on the pinion tooth is quite small and easy to miss.



-Doug

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #5 on: 04 Apr 2023 at 04:23 »
Cheers Doug, I did see a small mark like that but when I lined that up neutral was in the wrong place could the selector be wrong inside the box? Or could it be a pinion off a different box?

Neil

Offline Dads bike

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Re: New project 1937 aero 600
« Reply #6 on: 04 Apr 2023 at 10:33 »
Morning Neil
Some things to compare
You have the correct selector gate on the tank? see pic thatís neutral. Fully up is first, there is an inverted gate that will just about fit the tank, ie first fully down then one up neutral.
Rack and pinion. See pic and orientation of the mark on the pinion to the keyway, thatís the correct pinion.
That said the pinion is a taper fit to the selector shaft and located by a key, is the key in place? If not the pinion will move on the shaft.
The pinion must not be over tight on the taper it is very easy to break.
If you need a pic of the selector just say I will get one out.
If all tallies up then you should be able to adjust out the problem on the linkages

Steve

Offline Dads bike

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Re: New project 1937 aero 600
« Reply #7 on: 04 Apr 2023 at 10:38 »
A better pic of the rack and pinion
Steve

Offline Dads bike

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Re: New project 1937 aero 600
« Reply #8 on: 04 Apr 2023 at 10:50 »
A picture of the other tank gate 

Steve

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #9 on: 04 Apr 2023 at 11:23 »
Thanks Steve, yes my gate is like the top one and when I had the rack and pinion set as in your pics I could only seem to find 3 gears is there a chance I might need the inverted gate? The box is going to have to come off for more investigation as the shaft the pinion goes on does have some back and forth movement.

Neil

Offline Dads bike

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Re: New project 1937 aero 600
« Reply #10 on: 04 Apr 2023 at 13:25 »
Afternoon Neil
Providing the gearbox selector shaft (cam shaft) is correct you will not need the inverted gate for the tank.
The selector shaft should have no detectable end float, the parts book indicate that there is a thrust washer to the ball race end of the shaft, that would be a good place to start if you do have end float.
I guess that the pinion Is correctly keyed to the selector shaft.

Ref your previous post about the clutch slipping: Again the club spares did hold stock of the pressure plate springs.

Steve

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #11 on: 04 Apr 2023 at 14:03 »
Thanks again Steve, Iíll have the box out and check it all, ref the clutch I also had a quick look at that and it appears the last owner didnít use the brass ring with the ball bearings in but used loose balls as they all fell out when I took the springs off and these were much bigger than the balls in the ring so looks like they were just holding the clutch off.

Cheers Neil

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #12 on: 04 Apr 2023 at 21:46 »
So had another look this evening and wish I hadnít, Iíve bought a pup  :( the more I look the more I find wrong and I was told all was good, so rant over I need to knuckle down and get it sorted.

I can see a small mark on the pinion and when that is lined up with the mark on the rack I take it thatís 1st? Looking at the drum I take it there is no indent for neutral? Though the indent bolt is missing the spring and would it be a ball or bullet like shape object? So that does not help also all the rollers are missing from the final drive gear and any spacers.

Steve you mentioned a thrust washer for the pinion shaft should it be at the pinion end of the shaft or the far end? As there is a spacer at the far end between the drum and the bearing Iíve added pics hope they make sense.

Neil

Offline cardan

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Re: New project 1937 aero 600
« Reply #13 on: 04 Apr 2023 at 23:59 »
Hi Neil,
So sorry to hear of your troubles - happened to me a while back on something quite important, and it took me a long time to get the energy to do a complete rebuild on a machine that was said to be fully rebuilt.
If you can measure accurately the roller size you need I might be able to supply them - I assume they're just loose rollers? Keep in mind there might be some wear, so the shaft might need a light grind to get things round again. Depending on the size, I have some oversize rollers.
Cheers
Leon

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #14 on: 05 Apr 2023 at 19:33 »
Cheers Leon,

Itís very frustrating as I thought I was buying a minimal work project not a major one but too late now just need to crack on.

So the parts that were missing were the thrust washer for the drive pinion but found that in a box, the roller bearings and washers for the same pinion but stole them from my 250 box (so now need to replace them) and the detent spring and plunger (is this hardened because if not Iíll make one) so after putting it all together there are now 4 gears and even with the wear on the final drive it seems ok ish BUT the brass bush needs replacing how do I get this out? The bearings on the 2nd shaft (sorry terminology is rubbish) need replacing how do I get the bearing out the housing (chain side not kickstart side) and how do I remove the toothed kickstart gear so I can change the bearing on the main shaft? I presume itís screwed on?

Iíve added lots of pics one of which is of the final gear which is not very well lined up with the drive gear but looking at the wear thatís how itís always been oh and also the second shaft goes in the bearing very easily should this be tight.

Hope at least some of this makes sense.

Neil

Offline Dads bike

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Re: New project 1937 aero 600
« Reply #15 on: 05 Apr 2023 at 19:33 »
Evening Neil

So where to start?
Have attached a couple of pics to hopefully help.
First the bearing assembly you are missing, there should be an outer race, two end plates and a shim to go between the two rows of rollers, there should be 38 1/4Ēx1/4Ē rollers
The input shaft and output shaft. The solid shaft is the weak point, the case hardness is poor, so if either of the drive chains are over tightened it will score badly, the female shaft has a bronze bush so you will very probably need to have the shaft ground and a new bush made to a running fit ie no play, otherwise you will leak oil.
The spring loaded peg should be bullet shaped.
Will revert later ref setting the rack and pinion need to do a couple of measurements.

Steve

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #16 on: 05 Apr 2023 at 19:40 »
Evening Neil

So where to start?
Have attached a couple of pics to hopefully help.
First the bearing assembly you are missing, there should be an outer race, two end plates and a shim to go between the two rows of rollers, there should be 38 1/4Ēx1/4Ē rollers
The input shaft and output shaft. The solid shaft is the weak point, the case hardness is poor, so if either of the drive chains are over tightened it will score badly, the female shaft has a bronze bush so you will very probably need to have the shaft ground and a new bush made to a running fit ie no play, otherwise you will leak oil.
The spring loaded peg should be bullet shaped.
Will revert later ref setting the rack and pinion need to do a couple of measurements.

Steve

Hi Steve,

Many thanks think we were posting about the same time  :lol: just thought should the shim be hardened? And what is availability like on these parts as obviously Iíd like the replace the outer race and shim Iíve stolen and also the final drive shaft should really be replaced looking at the wear

Neil

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #17 on: 05 Apr 2023 at 20:44 »
Just discovered the reason for the discrepancy between the gears, it was the wrong way up and also the wrong one 15 tooth not 16 the original was in a box, bit worn but now sounds much quieter when turned by hand 🤦‍♂️

Neil

Offline Dads bike

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Re: New project 1937 aero 600
« Reply #18 on: 05 Apr 2023 at 20:47 »
Evening Neil
Yes I think we were posting at the same time.
Yes the shim should preferably be hardened, I donít know where you would get one from, Bearing supplier?
Have touched the bullet on the spring loaded peg with a file and itís not too hard, so if you can make one fill your boots. It does very little work to be fair.
Whatever you do, do NOT replace the bush in the female shaft with brass it will seize very quickly, use phosphor bronze, you will need to cut the old one out, preferably on a lathe
The ball races in the case, you will need to make a small L shaped tool to get behind the race and produce a small slide hammer, donít pry off the case it will brake the alloy. Heat the case prior to pulling them out they should not be very tight in the inlay material, Replacement bearings are readily available.
The kick start pawl can be very tight to remove as the operation tightens it on to the thread, Doug Kephart put a post regarding a tool and how to remove this pawl, just at the moment I cannot find it. DOUG CAN YOU POINT US IN THE DIRECTION?
The shaft that you think needs replacing! Take a look on eBay item No 224790373715, itís not mine so donít know the condition, but may be a cheaper option than refinishing the original plus you get a couple of other bits.
If you now have four gears I will back off regarding the selector shaft.
Are you looking to rebuild the machine as close to original as possible? Or are you just looking to produce a runner?

Steve

Offline Dads bike

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Re: New project 1937 aero 600
« Reply #19 on: 05 Apr 2023 at 21:06 »
19 tooth gear with one missing😩

Offline Doug

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Re: New project 1937 aero 600
« Reply #20 on: 06 Apr 2023 at 00:38 »
Quote
Doug Kephart put a post regarding a tool and how to remove this pawl, just at the moment I cannot find it. DOUG CAN YOU POINT US IN THE DIRECTION?

I remember discussing such with someone, but do not recall a post. I have done a search on it too with empty results. I also looked on my computer to see if I saved a sketch or drawing of the tool design, but again no results.

-Doug

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #21 on: 06 Apr 2023 at 08:42 »
Quote
Doug Kephart put a post regarding a tool and how to remove this pawl, just at the moment I cannot find it. DOUG CAN YOU POINT US IN THE DIRECTION?

I remember discussing such with someone, but do not recall a post. I have done a search on it too with empty results. I also looked on my computer to see if I saved a sketch or drawing of the tool design, but again no results.

-Doug

Cheers for the reply Doug Iím sure I can make something I presume itís a right hand thread?

Neil

Offline Red

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Re: New project 1937 aero 600
« Reply #22 on: 06 Apr 2023 at 14:12 »

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #23 on: 06 Apr 2023 at 21:42 »
Well thanks guys, with all the info you gave me a bit of luck a trawl through my Douglas spares box and the help of an amazing engineer I think Iíve a usable fully functioning 4 speed gearbox the output shaft is worn where the roller bearings go so either need a new one if anybody has one for sale or a grind and oversize rollers but I think it should be ok for now.

Now onto the next issue  :roll:

Neil

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #24 on: 07 Apr 2023 at 19:04 »
So next issues, the brakes did not work and I found out it was because they had the rear shoes in the front and vise versa and so were the brake arms. My problem now is are there any drawings/photos of how both front and back wheels go together with all spacers etc and also what thread is the bolt that holds the brake arm is it 1/4unc ? Because the builder seemed to like to use metric :shock:

Secondly is this the correct clutch release arm? Why is there a bracket in it and should there be that gap when itís fully clockwise also the thrust bearing I presume the lip side goes toward the arm.

Neil

Offline Red

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Re: New project 1937 aero 600
« Reply #25 on: 08 Apr 2023 at 10:12 »
Neil

They should be brake Bands not shoes - see the link below

Roy

https://www.douglasmotorcycles.net/index.php?topic=5978.msg21969#msg21969

Offline Red

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Re: New project 1937 aero 600
« Reply #26 on: 08 Apr 2023 at 10:23 »
Neil

Link below may help with your clutch problems

Roy

https://www.douglasmotorcycles.net/index.php?topic=6434.0

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #27 on: 08 Apr 2023 at 13:39 »
Thanks Roy and yes sorry I should of said bands I think Iíve sorted the brakes though the front one is a bit  tight even with the adjusting bolts  fully retracted so I think the springs are a bit weak or maybe the friction material has swollen  :frown: and Iím sure Iíll sus the clutch release it just seems to move quite a lot before it starts on the ramp.

My main issue now is the wheel spacers. Should there be a washer/spacer inside the brake plate or should the brake plate just pull up against the bearing nut? Also should there be any washers/spacers between the wheels and frame/forks either brake side or dust cap side because there wasnít one on the back wheel R/H side between the frame and dust cap and the dust cap is now damaged as it pulled into the frame slot.

Neil

Offline Red

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Re: New project 1937 aero 600
« Reply #28 on: 08 Apr 2023 at 17:30 »
Hi Neil

Without stripping the wheels on my bike I honestly can't remember. Attached is a parts list for the Aero and although there are no illustrations it may still help sorting out what spacers and washers should be there.

Roy

1936-37 Aero Parts List (3.4Mb PDF)



Image added and file converted from attachment to linked - Dave, 09Apr2023
« Last Edit: 08 Apr 2023 at 18:27 by Dave »

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #29 on: 08 Apr 2023 at 19:45 »
Thanks Roy it does list washers and distance washers but without a diagram or how many are used as well itís a bit tricky, Im sure Iíll sus it out one way or another I might even take my 250 apart that may well be similar  :)

So Iíll now ask about the girder forks then  :lol: how easy are these to take apart and put back together? I only ask as it looks like it has home made parts but luckily I think I have aero 600 parts that came with my 2nd 250 as they are too big for the 250 pics attached.

Cheers Neil

Offline Red

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Re: New project 1937 aero 600
« Reply #30 on: 09 Apr 2023 at 10:20 »
Hi Neil

I don't think my forks are the correct for the Aero. I did strip them down without any major problems. They have lock stops fiited whereas I believe the 1937 models had a slight change to the headstock and lock stops were no longer fitted. See photo.

All the best

Roy

Offline cardan

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Re: New project 1937 aero 600
« Reply #31 on: 09 Apr 2023 at 12:11 »
Chalk and cheese forks! Your might not be exactly right for your bike Roy, but they look lovely. Yours, Neil, look... is "ghastly" too harsh?

99% of girder fork designs - from the original Druid in 1907 - rely on having two rigid assemblies, each of 2xspindles + 2xlinks. These must always bolt up dead tight, and (importantly) parallel. I don't think yours will do this Neil? It looks like the spindles just go though holes in the links? There are various ways of doing it - shoulders on the spindles, threaded links + locknuts, etc., but rigidity is the key.

Then there's the "parallelness" of the holes to sort out: the three on the fork (upper spindle, lower spindle, and axle) and the two on the head stem (upper and lower spindles). I discovered long ago that I couldn't do this myself, but I have a local machine shop who can do it for me. All five need to be parallel - tricky to set up but very rewarding if done properly.

Then there's dealing with the end float. Again lots of ways from different manufacturers, but important.

And finally there's often a friction damper, which is never (?) implemented by tightening the spindle nuts!!

Sounds simple, but there's a lot of work sorting out an operational and safe set of girder forks. Hopefully your spares will provide the missing bits to get you started.

Cheers

Leon

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #32 on: 09 Apr 2023 at 13:50 »
Thanks again Roy, yes when I first saw the bike I thought the stops were missing then read that the design changed on the 1937 model.

Cheers Leon, the parts that have been made do look terrible (not by me) and I think the top link bars do not come up to a shoulder like they should but the spares I have do (bottom photos) and I donít know if itís the spring or the way they are built but there is hardly any movement in them. So is there a write up anywhere on how to take them apart? Will they go with off with a boing.

Neil

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #33 on: 10 Apr 2023 at 15:49 »
Hi Roy, any chance of a pic from the front and above of the forks please I now know why mine didnít move they were tightened up on the top to take up the gap I presume there should be shims? And I presume it should be the same either side? The pic is the total gap.

Neil

Offline Doug

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Re: New project 1937 aero 600
« Reply #34 on: 10 Apr 2023 at 16:54 »
Here is a set of 1936 Aero fork links. Far as I know, introduced on some of the 1935 models like the Endeavour and Blue Chief with a new pattern of lightweight forks and ran through the 1938 models. They are 3/4 x 1/4 inch flat bar, with the lower links having a 2-1/2 diameter x 1/8 inch thick washer brazed on for a damper washer surface. One set reamed and one set tapped for the spindles.



The 1934 and most of the 1935 heavyweights (excluding those mentioned above) had a forged or cast steel lower link, but essentially the same flat bar upper link. If I remember correctly, those used 1/2 inch spindles and the Aeros used 7/16.

-Doug

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #35 on: 10 Apr 2023 at 19:10 »
Hi Doug, and yes thatís exactly what I now have as your picture but I presume itís ok to fit washers? I see they sell knurled ones for girder forks and itís the only way I can get mine to seem to work nicely also how thick should the friction washer be? Mines quite thick so might be why I need washers on the bottom arms and also what sort of spring device would be used behind the knob to put more friction on the forks Iíve found Star shaped ones online but these would not work on the arms I have.

Thanks Neil

Offline cardan

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Re: New project 1937 aero 600
« Reply #36 on: 10 Apr 2023 at 23:54 »
I'm not understanding these forks very well.

I assume that the spindles are stepped at the "reamed" end so that part of the assembly process is to tighten the link against a shoulder with the nut? I hope the spindle doesn't just go through the hole in the link without fastening?

Sorry for banging on, but the fork is a vital part of the bike if you want to stay alive. It needs correct design and materials to avoid disaster.

The brass knurled washer used by Norton and others was to help get the end float right: when correctly adjusted it should be possible to just turn the washer with fingers.

Leon

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #37 on: 10 Apr 2023 at 23:59 »
Hi yes they are stepped so they tighten to a shoulder on the off side

Neil

Offline Doug

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Re: New project 1937 aero 600
« Reply #38 on: 11 Apr 2023 at 00:25 »
The star/spring washer has a notch to straddle the link.



The friction washers are a brass filament reinforced, woven material. I measure from 0.107 to 0.117 thick, though I have no idea how much wear might have occurred.



I do not think Douglas tended to fit wear washers between the girders and the links. However in the bag of original nuts for the fork spindles there are two plain washers. I did not make a note as to where they were positioned, but I suspect they went at the top of the girder as otherwise the face there is flush with the surrounding lug and could use something to make the bearing surface stand proud so the girders did not rub where they ought not to. It would require measuring the width across the girder and the width across the top yoke to see if washers were needed to make the dimensions equal. You can probably just as easily do that on your bits.

-Doug

Offline cardan

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Re: New project 1937 aero 600
« Reply #39 on: 11 Apr 2023 at 08:01 »
Hi yes they are stepped so they tighten to a shoulder on the off side
Excellent - I will stop worrying now. Seen too many shockers...

Leon

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #40 on: 11 Apr 2023 at 09:02 »
Thanks Doug thatís exactly the info I needed and you have described it exactly how I should have but what I meant to say didnít come across very well in my frustrated ramblings. I will do some measuring to make some sized washers for the top links between them and the girders because the girders are narrower than the top yoke and the reason Iíve had to use a couple of washers on the bottom yoke is because the friction disks are probably twice as thick as the ones you stated. So I presume washers should be equal either side of the girders as it seems to sit more to one side.

Cheers Leon and as above I think my ramblings got lost brain and keyboard.

Thanks guys any info is greatly received Neil

Offline Bob M

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Re: New project 1937 aero 600
« Reply #41 on: 11 Apr 2023 at 09:50 »
Some manufacturers used red fibre washers instead of those knurled steel washers and these tend to get discarded during disassembly as many donít understand their significance.
I currently have a 1939 Montgomery Terrier in my shed that has red fibre washers on one end of the links and Thackeray washers at the other. In the 1930ís Matchless also fitted red fibre washers.
Possibly Douglas did also?

Cheers,

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #42 on: 11 Apr 2023 at 20:24 »
Cheers for the reply Bob M, had another look today so have an update that maybe of some interest the top yoke is 5.3785 and the girders are 5.2000 or as best as I could measure them so the makes a difference of 0.1785 divide by 2 and that makes for a spacer of 0.08925 for each side so allowing for my measuring errors Iím going to make 2 x 3/32 spacers for the top link and see how it goes as for the friction disks the ones that were fitted were approx 0.2200 so much thicker than listed by Doug so this would be the reason why I needed spacers on the bottom yoke.

Iíve yet again been very lucky the friction disks on my 2nd aero 250 were actually too thin and I had used a spacer disk (not ideal but all I could do at the time) so I took them off and low and behold the thick ones I had on the 600 fitted the 250 and the ones on the 250 (approx 0.1140) fitted the 600 and I no longer needed spacers on the bottom yoke  :mrgreen: so I think once Iíve made the spacers the girder forks should be all ok.

An interesting thing is and Leon you might be able to help here but the link arms/friction arms are totally different on this 250 they have hollow shafts on them and thereís no shoulders etc and the spindles are the same diameter for the full length with the same thread both ends but yet again one arm is threaded and the other not.

Neil
« Last Edit: 12 Apr 2023 at 08:54 by Tazmantic »

Offline cardan

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Re: New project 1937 aero 600
« Reply #43 on: 12 Apr 2023 at 00:02 »
Hi Neil,

The links with the "built in bushes" are either BSA or copy of BSA - if you clean the paint off you might find the piled-arms logo stamped on them. They were used from the early 1920s well into the 1930s. There's a lot to like about the design in that it's rigid, has a large wearing surface, and is unlikely to shear (as a small-ish spindle and a flat-plate link might).

All the stuff we play with now is so old it's hard to know what was original! I think we can only do our best: measure, plan and make stuff that works the best it can. Re spacers for spindles and links, keep in mind that if holes are worn and (particularly) not exactly parallel, the links will work to one side so beware of using anything soft for washers. Druid forks for a long time (from 1907!!) used Thackaray washers (the original ones are flat-section, double wound, with parallel faces) to provide a spring tension to take up the end float, but careful setup is just as good. But do choose spindle steel carefully - "silver steel" still gets suggested but should never be used because doesn't have the core strength and is more likely to snap than bend.

Cheers

Leon

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #44 on: 12 Apr 2023 at 08:06 »
Cheers Leon,

So it looks like my 250 may have bsa lower links thatís quite interesting maybe if theyíre a better design I should put them on the 600?? I have a feeling the lower spindles on the 250 may be silver steel but all the rest are original and I did read what steel should be used but canít remember where now. As for the star spring where could I get one of these? Iím sure I wonít get an original but I could slot one to fit.

Cheers Neil

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #45 on: 12 Apr 2023 at 22:54 »
Well thanks guys with all the info looks like Iíve now got properly set up girder forks on both the 250 and 600 there was issues with both so many thanks, on to the next problem  :cry:

Neil

Offline Dads bike

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Re: New project 1937 aero 600
« Reply #46 on: 14 Apr 2023 at 10:00 »
Morning Neil
Finally been able to catch up on your thread, good to see most things have been answered for you and you now have a good set of forks. One or two points that I can see remain unanswered hopefully I will cover.

The clutch operating arm, this looks like someone has provided a bodge for a return spring from the arm to the lower part of the chain case. The spring should be a volute spring that the control cable and adjusting screw fit through, You can if necessary use a coil spring cut to length.

The front axle, there are spacers both sides, see the pics, the one on the brake plate side should be thick enough so that when the nut is tightened the brake plate edge has clearance between it and the fork blades.
The opposite side has a spacer that can be removed to fit the optional extra speedo drive.
Note the penny washers on the outside surface of the forks, these are a neat fit into the spot drilling on the forks and axle diameter so locate the the axial in line and prevent misalignment.

The brake lever holding bolt.is 1/4Ē dia 26tpi, threaded length 9/16Ē with a shank length of 2 3/4Ē note the over size head 1/2Ē across the flats.

Thanks for looking for the gear wheel.

Steve


Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #47 on: 14 Apr 2023 at 17:22 »
Thanks Steve thatís great think I had almost sorted the front wheel there was allsorts of washers and spacers in there (see pic) but is there also a washer/spacer on the inside of the brake plate between the plate and the bearing nut? Also the front brake is dragging quite bad so Iím not sure if the springs are worn (though it lists different part numbers for front and rear brake springs) or the lining is just too thick.

Thatís interesting about the spring there is just a coil spring on there now so what size should the volute spring be?

I made a couple of bolts for the brake arms today so hope they are the correct size.

The Gearbox bolts are too short only holding by a few threads so need to get some more they are 3/8 x 20 tpi but are they UNF or BSC?

Cheers Neil
« Last Edit: 14 Apr 2023 at 17:27 by Tazmantic »

Offline Dads bike

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Re: New project 1937 aero 600
« Reply #48 on: 14 Apr 2023 at 18:31 »
Evening Neil
Bear with me I need to drop my front wheel out to be sure I have my facts right as the parts list does not list a lock nut that I think should be there.
The brake drum side bearing abuts the shoulder of the spindle and is held with a nut/spacer and I think is locked with a thin lock nut all of these together allow the break plate a little clearance to the break drum, if you have a spacer in there I think thatís where the lock nut should be?
If the breaks are dragging itís most likely the material is too thick as the return springs on the band are fairly robust /strong.

Take care with the gearbox mounting bolts, they go into a blind hole and need to be the correct length or you will very easily punch a hole into the box, they will be BSC thread.
Steve

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #49 on: 14 Apr 2023 at 19:29 »
Cheers Steve, yes a thin lock nut would sound right now you mention it and if I push the brake arm the wrong way it does release but I must admit it does not move much at all either way.

I did think that it would possibly be BSC but canít seem to find any bolts so might have to make some.

Cheers Neil

Offline Red

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Re: New project 1937 aero 600
« Reply #50 on: 15 Apr 2023 at 10:33 »
Neil

On the front brake the operating rod is fitted with what Douglas called a spring box. Is this fitted on your bike. Without the spring box there is a good possibility that the brake will not free off completely. See link below. I had to make one for my son's Aero for the same reason.

Roy

https://www.douglasmotorcycles.net/index.php?topic=6194.msg23211;topicseen#msg23211

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #51 on: 15 Apr 2023 at 20:25 »
Thanks Roy I had noticed that most 600 had a steel rod and mine does not so looks like another part I need to make  :o neither of my 250s have this rod so yet more wrong with my bike.

Neil

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #52 on: 16 Apr 2023 at 20:48 »
So having a better look at the drawing I presume the cable adjuster goes in the top of the spring box? Also does the ID of the spring fit over the adjuster?

Neil

Offline Doug

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Re: New project 1937 aero 600
« Reply #53 on: 17 Apr 2023 at 07:19 »
The cable adjuster projects into the spring box. The spring does fit over the adjuster thread, and abuts the shoulder in the brake rod.

A picture of the top of the brake rod:



-Doug

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #54 on: 17 Apr 2023 at 10:32 »
Thanks Doug thatís great should the 250 have the same?

Neil

Offline Red

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Re: New project 1937 aero 600
« Reply #55 on: 17 Apr 2023 at 12:05 »
Hi Neil

If you look at page 17 of the numerical parts list yes ALL the Aero models were fitted with the same front barke arrangement. There are a few minor changes to the 1937 bikes (model F) when straight pull levers were fitted, but the spring box was still used - part numbers 5299 and 18421 and operating rod C/11437.

Roy

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #56 on: 17 Apr 2023 at 14:54 »
Thanks Roy, everydays a school day as they say so looks like I need to make 3 sets :shock: and thatís why there are 2 different return springs listed for front and rear brakes I was thinking they meant the ones in the drum on the brake band, so I presume the one listed for the rear (11350) is the one on the brake pedal?

Neil
« Last Edit: 17 Apr 2023 at 17:39 by Tazmantic »

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #57 on: 17 Apr 2023 at 22:07 »
Sorry another thought does anyone one know the spring size? Length and wire gauge?

Neil

Offline Red

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Re: New project 1937 aero 600
« Reply #58 on: 18 Apr 2023 at 10:43 »
Hi Neil

I think this is the one I purchased from Feked.

Roy

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #59 on: 18 Apr 2023 at 13:29 »
Cheers Roy, I did find that one earlier and wondered if that might be it. Appreciate the help again.

Neil

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #60 on: 18 Apr 2023 at 20:47 »
So springs and some bar ordered did you make the lower rod out of 3/16 and what clevis fork did you use?

Neil

Offline Red

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Re: New project 1937 aero 600
« Reply #61 on: 19 Apr 2023 at 09:43 »
Hi Neil

Yes I just copied the dimensions Chris provided so I used 3/16 inch rod. The fork was made out of a small block of steel with plenty of cutting and filling. I don't know whether you could buy anything similar. Others may have better ideas.


Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #62 on: 22 Apr 2023 at 21:09 »
Cheers Roy, my metal didnít turn up so made some bolts to hold the gearbox today as last owner thought 3 threads was okÖ.not original and probably the wrong thread but match the thread in the box and should work ok so that will do for me  :o:

Neil

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #63 on: 07 May 2023 at 16:28 »
Well hereís my attempt hopefully it will work  :|

Neil

Offline Red

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Re: New project 1937 aero 600
« Reply #64 on: 07 May 2023 at 17:42 »
Hi Neil

Looks good

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #65 on: 07 May 2023 at 23:52 »
Cheers, hope it works  :roll:

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #66 on: 15 May 2023 at 19:34 »
So with everything Iíve found decided that the ďrefurbed engineĒ needed a once over just to check and yep thatís just as bad as the rest of the bike, I personally wouldnít let the bloke who built this engine pump my tyres up  :evil: loose nuts and bolts and spacers missing not to mention all the wrong nuts and bolts anyway main question is what implications does the aluminium being broken out on the engine case main bearing timing gears side (pic attached) has anyone run an engine like this? Will it cause major issues?

Neil

Offline cardan

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Re: New project 1937 aero 600
« Reply #67 on: 16 May 2023 at 07:46 »
Hi Neil,

That doesn't look too good, but maybe it's not as bad as it looks.

I wonder how it happened - knocking the end of the housing out is a difficult thing to do with an ordinary engine malfunction? Perhaps it was done on the bench trying to get the bearing out?

To trust the engine you need to know that the bearing is properly seated in the crankcase. There's very little end thrust when the engine is running, so the missing alloy is not a problem provided there is a rim on which to seat the outer bearing shell. There might be more oil than usual blowing into the timing chest through the bearing, which may or may not be a problem. Hard to say without running the engine and seeing if your right foot is drenched in oil on the maiden ride!

If the bearing looks securely seated in the case, and the crank end float is withing tolerance, you could run the engine and see what happens. Probably the proper thing to do (aghh) is to strip the engine entirely and have a proper look?

I empathise.

Leon

Offline eddie

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Re: New project 1937 aero 600
« Reply #68 on: 16 May 2023 at 08:45 »
Neil,
       To add to what Leon has said - there should be little or no force on the timing side bearing if the engine is properly assembled. In fact the only end thrust on the crank is in the opposite direction, when operating the clutch!

  Regards,
                Eddie.

Offline Doug

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Re: New project 1937 aero 600
« Reply #69 on: 16 May 2023 at 16:02 »
Some of the Douglas models had cam spindles drilled from the rear for a passage for oil mist from the crank chamber proper to lubricate the cam bushings. I cannot remember offhand if the Aero models still had this, but they probably did. So a loss of 'back pressure' venting into the timing chest might reduce the amount of lubrication forced through the passages. On the other hand the increase of oil mist getting through due to the missing crankcase wall will mean more oil vapor swirling around in the timing chest. From there it would have to work its way into the bushings. It also means more oil for the scavenge pump to deal with.

Structurally it is not that big a deal, so long as there are no loose bits ready to fall off and jam the works and no cracks that might propagate. It looks like there is enough there to locate the bearing. A snap ring would suffice.

Replacing the end wall can be done, but it is a rather involved machining process of making an insert (usually steel) to replace the bearing bore and face. The attached images are of a 1931 350cc crankcase, during a period when Douglas was using a timed breather and so the presence of the end wall is important to the function.





I would say leave it be, while it is not ideal it is not a show stopper.

-Doug




Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #70 on: 16 May 2023 at 21:18 »
Thanks for all the replyís guys and information Iíve added a few more pics to show what itís like now Iíve stripped it down for you to look at I was hoping it was just the disc that was broken and what this might cause but think the pics say it all. I do have some other cases but none match and Iím not sure what year/cc they are from as the bearing disc are different and the mag mountings are different if I wanted to use the l/h case thatís fitted at the moment, also the bearings are not tight on the crank they slip on quite easy  :( think I might need a new engine or just sell as itís just one issue after another.

Neil
« Last Edit: 17 May 2023 at 08:17 by Tazmantic »

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #71 on: 16 May 2023 at 21:21 »
These are the cases I have, the first is the current one to show the mag difference, any ideas what the other 2 are??

Neil
« Last Edit: 17 May 2023 at 08:17 by Tazmantic »

Offline eddie

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Re: New project 1937 aero 600
« Reply #72 on: 17 May 2023 at 08:42 »
I reckon that bearing housing damage was caused by a ham-fisted owner with a club hammer trying to shift a stubborn flywheel!

  Regards,
                Eddie.

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #73 on: 17 May 2023 at 09:49 »
Hi Eddie, itís a bit of a mess for sure but after a sleepless night thinking about it I thought maybe I could buy a bearing with a metal seal on one side but they donít seem to be available (thatís if Iím searching the correct bearings 25x62x12 (98305)) so Iíve decided my only option for the time being is to fit the bearing with retainer (though itís not loose in the case but to just make sure) and machine up a thin disc to cover the bearing on the timing side and be held in by the gear. Wonít stop all the oil mist but might reduce it significantlyÖ machining the case out and inserting a metal sleeve like Doug said would be the better option but not sure my machines or me are up to that job.

Neil

Offline eddie

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Re: New project 1937 aero 600
« Reply #74 on: 17 May 2023 at 10:09 »
Neil,
       Another option would be to machine the crankcase back to the face the bearing sits against, and somewhat larger (68mm?). Then turn up an alloy washer to replicate the damaged bit of the casting, and get it laser welded into place. Laser Welding is not cheap, but it hardly imparts any heat into the casting, so doesn't cause any distortion. A couple of our Surrey/Hants members have resorted to laser welding for repairs and have been very impressed with the results. One was a modification to a magdyno end plate to make it marry up to a Speed Special crankcase - the other was a repair to a cracked Sunbeam S7 rocker cover.

  Hope this is of some help,
                                        Regards,
                                                     Eddie.

Offline Dads bike

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Re: New project 1937 aero 600
« Reply #75 on: 18 May 2023 at 11:32 »
Morning Neil
Sorry I have had little input to your posts, my attention has been directed elsewhere unfortunately.
Let me try to answer your latest questions.

Leaving the 250 & 350cc machines to one side. What You have in your latest pictures, is one of each, of the three 5/600cc Aero engine types produced, do you have the flywheel side, this has the engine No stamp on it.

Picture 1 with the cast magneto stand, this is the correct casing for your 1937 machine, this crankcase type would be prefixed 6P for 1937 and 6Q for 1938

Picture 2 this engine type dates to the later 1936 Aero period, it has a separate removable magneto stand, and was the first of the longer crankshaft models it only came in the 600cc variant and the engine No was prefixed 6M.
In your picture there are two holes drilled in the casing at the back of the main bearing housing, this is another bodge someone has done to allow them to punch the bearing out.

Picture 3 this is the early 1936 engine type and was used for both the 500cc units and the 600cc units and would be prefixed 5L or 6L, again with the removable magneto platform, however this crankcase with the crescent moon shaped oilway at the back of the main bearing
accommodates the shorter crankshaft type. The shaped oilway allowed more oil vapour to the additional components of the shorter crankshaft ie the extra parts for the oil pump drive and the Dynamo drive.

Your comments around the crankshaft fit.ie itís loose within the bearing.
The two main bearings are shrink fits into the crankcases housing and therefore tight on the outer race, assembly of the unit is allowed by the crankshaft being a push/sliding fit into the inner race. Crankshaft end float is set with thrust shims on the flywheel end of the crankshaft and with the correct size of gasket between the crankcase halfís, look for 6thou of an inch end float when fully assembled.

The damage to your crank case looks like some buffoon has attempted to take the crankshaft out without removing the oil pump drive and timing gears as there is still a slight step at the back of the bearing, ie itís all gone inwards rather than outwards.
I agree with Eddy, the way to fix would be to let in a thin ally washer shaped piece.

Note that all the crank cases are all matched pairs, stamped on the case under the front cylinder so if you do go along the line of mix and match you may have to do a little alignment work.

The timing chest main bearing is SKF 6105 with the dimensions you stated with a CH3 clearance and 05 to the outer race.
Steve




« Last Edit: 18 May 2023 at 13:08 by Dads bike »

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #76 on: 19 May 2023 at 08:21 »
Thanks for all the replies guys I do really appreciate it, I do have 2 flywheel side cases (pics attached) one is the original engine but was removed as the mountings are corroded (I thought one of the timing side cases was a match but not) I also have a 500 flywheel side case but that doesnít match either of the timing side cases either  :frown:.

The ally washer idea is definitely a plan or a steel cup insert but there are other issues with this case (one mounting lug bodged, one barrel stud bigger, all timing cover bolts drilled out bigger) so Iím wondering if itís worth doing or trying to find replacement cases even though the previous owner went to the hassle of changing the engine number with the dvla.

My idea was as Iíve found a slightly thinner bearing for the timing side was to make a thin ally washer to put in behind the bearing to act like the original case and stop the oil mist but I am really struggling to part off a thin enough washer as it keeps wandering off (expect itís my equipment) so another plan is needed.

Cheers Neil

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #77 on: 20 May 2023 at 13:44 »
So hereís a couple of pics of the bodge I mean precision fix, a thin steel washer, slightly cupped to miss the inner race and original bearing used, so will just need to check the end float. So a couple more questions I presume the bearing on the flywheel side should be self aligning the one that was fitted is fixed and also Iím going to probably strip the crank down and make sure that is all okay as the bolts that hold the crank together on one side you can see the end on the other. Itís quite sub flush so Iím not sure whatís going on there also Iíve attached a picture showing the conrods should the slots be at the top or the bottom as one is top and one is bottom and also should that hole be in there.

Cheers Neil

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #78 on: 22 May 2023 at 18:56 »
Stripped crank today bolts were different lengths also managed to get it apart by holding the web and tapping the bolt so now think I probably need a new crank as well. Con rods look ok and crank pins might just be acceptable though all the rollers did fall out of the cage on one big end the other stayed together. Last pics are how far I could push the crank back together by handÖ.

Neil

Offline Tazmantic

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Re: New project 1937 aero 600
« Reply #79 on: 24 May 2023 at 11:16 »
So I think this crank is going to have to do but would like to replace a few parts namely (and I hope these are the right bits)

18471 crank pin bush
18523 set screw (securing webs)
16832 locking washer for screw

Are any of these parts available as Iíve looked on the spares list and all I can find is the lock washer but it doesnít list one for Aero just EW T6 and S6

Neil