Dougles 350 1925 motor + clutch

[anfänger]

Hi,
i want to do maintenance at Flywheel and Clutch, but i cannot dismantle parts. have someone experience to do this on right way.

BR, Ernst

[anfänger]

Dear Douglas specialists I need your help,
I can't disassemble the flywheel ( Flywheel and Back Plate)

The manual describes how to disassemble it, but I don't understand how it works.
Please support.

Thanks & Greetings Ernst

[eddie]

Ernst,
          The backpate on your flywheel is probably just stuck due to not being disturbed for some time. Replace 4 of the screws but leave them undone a few turns. Then working from the front of the flywheel, use a soft drift in the 4 holes and 2 slots around the centre of the flywheel to knock the clutch plate back. The backplate should then pop out of the register in the flywheel - the 4 screws will prevent everything just falling apart as soon as the backplate moves.
   Hope this helps,
                           Regards,
                                        Eddie.

[anfänger]

Hello Eddie,
Many thanks for your information. I immediately tried your application, unfortunately without success.Maybe my new photos will help you.

[Hutch]

Hi Ernst,

Interesting problem and one I have not encountered (well one back plate may have been a little more difficult than others to get off but it was not that difficult). I had a quick look at some flywheels and on some I noticed that underneath the back plate there were some signs of corrosion where the plate would contact the flywheel (i.e. the Nickel Plating is long gone). On some it appears to be on one side of the flywheel only. I can only guess that this is due to possibly moisture gathering inside the flywheel when the engine has been sitting in the one position for a long time (EDIT:- or the engine stops in roughly the same position all the time) and has collected at the bottom? The asbestos dust from the clutch also collects in this area so probably doesn't help in allowing things to dry out? (just a guess). On one particular flywheel the whole face where the backing plate goes was badly corroded.
 
I think I would try to use the lever method you have already tried in a few different places around the opening in the back plate and possibly try two levers opposite each other at the same time, rather than one side only? You may find a position where the plate will pop off. A little gentle heat from a propane / MAP torch may help but don't overdo things if you want to keep the plating in the same condition as it is now (that might not matter.....?).

EDIT:- The reason the back plate was slightly difficult on one flywheel was that there were some dents in the periphery of the flywheel that had slightly peened over the edge of the machined hole for the back plate preventing it from coming out easily - maybe double check that you have a clean "gap" all the way around?

EDIT:- Maybe try a different lever to get more pressure on the back plate? i.e. twisting a flat blade screwdriver (or different implemet) in the gap between the back plate and driven plate rather than levering off the chain wheel on the driven plate?. Be careful tho' as on CW edge of back plate is not reinforced and may bend.

Best of luck!

Cheers

Hutch

[anfänger]

Hello Hutsch,
Thank you for your detailed description.
1) The clutch worked well from the start. I disassembled it for the necessary maintenance (see photo above)
2) I've tried many different tools with no success. No matter which method I used - no success and no movement at the gap between flywheel and plate.
3) Next try - heat the whole wheel - as you mentioned - with an electric hot plate (like an oven) so there is no risk of damaging the surface!

Br, Ernst

[Hutch]

No worries Ernst,

Looks like it is being a bit stubborn!

One aim is to try and get a heat differential - in this case maybe heat up the flywheel rim reasonably quickly with a propane torch so that the flywheel expands a little before the back plate has chance to catch up and expand due to heat being  transferred to it by conduction (i.e. don't put the flame anywhere near the backplate) If the back plate expands due to the heat applied to the flywheel rim, the the small gap and movement you were trying to create will go away and things may be just as tight as before...but a lot hotter. So you may get a small window of opportunity to try the levering with the flywheel rim  heated up. If it doesn't work first time let it cool down and try again - maybe with a little bit more heat and so on.

An oven will heat everything up fairly evenly and maybe not give you a decent heat differential that will help things come apart? It may help free up some corrosion tho'.? Worth a try tho' if it is easy to do - Warning -if using the domestic kitchen oven best that "her indoors" doesn't know anything about it !! :-)

cheers

Hutch

[anfänger]

Hello Hutsch,
done! According to the saying "Never give up". Now please let me know what I need to do for proper maintenance. Is it enough to clean all parts, or is it necessary to create a new surface (galvanize).
How can I disassemble the sprocket and chance
 the balls

BR,Ernst

[Hutch]

...... Is it enough to clean all parts, or is it necessary to create a new surface (galvanize).
How can I disassemble the sprocket and chance
 the balls
....

Hi Ernst,

Great that you managed to get the back plate off!

If, as you say, the clutch was working properly before disassembly I would tend just to inspect carefully and clean everything, re-assemble and lubricate as per the instructions in the Douglas Handbook (you need some lubrication of course, but too much is obviously not a good thing). If anything is not working properly afterwards at least it will be easy to disassemble now :-)

The clutch driven plate with the sprocket (1932D) should just slide off the outer clutch plate (1927D). I suspect there is corrosion / hardened grease etc on the bearing surface on the inside of the sprocket (below the balls)  preventing it from sliding off (i.e. jamming up on the balls). Trying to slide it off evenly rather than one side only as in you picture may help or you may need to use something liquid to loosen the rust/crud. With whatever you use be careful not to damage the friction material. Having a shallow bath of suitable liquid and placing just the sprocket into it with the outer clutch friction material clear of the liquid might work? (Don't know as have not tried this method, but  I have used penetrating oil and rust converter to get a badly corroded EW version apart. The friction material was worn out so didn't have to worry about damaging it....).

Another thought is that the balls are also acting as a cam and locking up due to them riding up on the groove (as a result of the friction from corrosion / crud), maybe get a piece of suitable size plastic tube to hold the balls down in a relatively "slack" position and try lifting the outer clutch plate off?

Inspect the driven plate for cracks. Also where the holes where the driven plate is rivetted to the sprocket can wear and become elongated so check that the plate is firmly attached to the sprocket and doesn't move.

Yet again - best of luck!

Cheers

Hutch

[anfänger]

Hi, Hutch,

many thanks for big help.
I have, hopefully last question about this issue - can you tell me the sice of fixing srews (Flywheel and back plate)

Br,
Ernst

[Doug]

7/32 - 24 BSW

[anfänger]

Hi,

please can i get bearing sice from crankshaft - (double main ball bearing and the bearing other side)

I can not read the sice on bearings any more.

BR,
Ernst

[douglas1947]

Ernst,

I had a overhaul of a later model some years ago, but may be you have the same size of bearings in your engine.
Please measure your bearing, I think they are metric and easy to get.
The double roller bearing on drive side could be 30x60x20 is a 4206.
May be the timing side one is a bit special, may be it is also metric but extra small?
Please let me know.

Michael

[anfänger]

Hi Michael,

i have a different bearing sice 20x52x22mm. it is of sure a metric bearing, but i never found it in a list.
The bearing on timing side is not dismantled yet

BR,
Ernst

[douglas1947]

Hi Ernst,

sorry, but I have no experience on the earlier Douglas type engine and I can not give help to you.
I hope someone of in the forum will give you informationwhat kind of bearing will work in your engine.

Michael

[douglas1947]

Hi Ernst,

if the drive side bearing is outer dia 52mm, inner dia 20mn and 22mm wide this bearing will fit:

 Schrägkugellager / Kugellager 3304 offen 20x52x22,2 mm

Michael

[anfänger]

Hallo Michael,

many thanks for information.
First, my Bearing maessuring was wrong - 20x52x21 it is a 4304 Bearing. I want to put in a RS version!! is that OK?
The Bearing an the other side - i can not move out Crank and Bearing - i dont no wy??

BR Ernst

[douglas1947]

Hi Ernst,

using a RS version of the bearing is a good idea (open up one side for oil cirulation).

If the crank and bearing on timing side do not come out you can try to warm up.
I have good results witha cooking stove. But I must tell, I use an extra one only for my use. It is NOT the one in our kitchen (I´m afraid my wife would get very angry!)

Michael