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31
Douglas Motorcycles - General Discussion / Re: 1931 t6 carb
« Last post by derek morgan on 11 Jan 2019 at 09:30  »
thank you very much for your advice Michael, I think you are spot on and that the problem is coming from the needle and bowl, will keep you updated, regards derek
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Douglas Motorcycles and Parts Wanted / Re: Clip for Footrest Rubber
« Last post by douglas1947 on 11 Jan 2019 at 06:05  »
I have no luck to send a photo!

Michael
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Douglas Motorcycles and Parts Wanted / Clip for Footrest Rubber
« Last post by douglas1947 on 11 Jan 2019 at 06:02  »
On my footrest  is 1 clip for the footrest rubber missing.
I would like to get one, in any condition or a reproduction.

Michael
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Douglas Motorcycles and Parts For Sale - Private / Re: Veteran Forks
« Last post by GlennMckenzie on 10 Jan 2019 at 22:20  »
Prefer trade for Veteran Druid Forks or a good early Post Mount Seat (pan type).
Cheers Glenn
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Douglas Motorcycles - General Discussion / Re: DT/SW5 Engines
« Last post by Buzzie on 10 Jan 2019 at 21:59  »
Doug

I have reflected on your notes about the bottom end of the first engine.

I don't have any notes or pictures from the engine builders. Having said in my experience that wouldn't be normal practice over here. We tend to chose engine builders carefully based on reputation and first hand experience of ourselves and our close circle, and then take them on their word for their work.

I fully accept your warnings about what should be done, and what could or could not have been done. I too think that they wont have built a DT engine before. But they must have some experience to have the confidence in their ability to do the work. They are a serious engineering company and there was none of that characteristic sucking though the teeth you normally get in the UK when they are worried about a task! I guess I just have to try and pick a way of minimising the risk by balancing the risk of their work being bad, against the risk of undoing good work which I cant get rectified.

So my plan is to split the crankcase and inspect the assembled crank as far as I can with a view to assessing the state of it and the quality of work done using your comments and common sense, before deciding what to do next. That decision will probably be the most difficult part of this phase of work.

I have in total three crank shafts, and five counter weights. At the moment I have no way of knowing the state of the crank and two counter weights in engine 1. The second crank came with engine 2 and has two loose counter weights and no cotters. The third crank I bought on ebay from someone else. It has one conrod with bearings and a counter weights with cotter fitted. I also have another loose conrod with no bearings.

The second crank isn't too bright. It was rusted on the surface in places, including on the bearing surfaces, I have polished this out and there doesn't appear to be any significant elliptical wear, although both big end journals have about a thou of taper on them. They also have some very light pitting where they were rusty. The counter weights are both marked F, and their batch numbers don't match the crank or each other.

The third crank is very rusty, and the counter weight is also stamped F, and its batch numbers doesn't match the crank or anything else I have! So I get the feeling that sorting out engine 1 will be a breeze compared with achieving my aim of getting good quality components in engine 2! I know in my gut I need a new crank and new conrods for that engine, and finding the crank at least will be a big task.

On a more positive note I have laid out all the components I have earmarked for engine 1. There are a few things missing, but not many. My next job is to list the missing items. I have also laid out the bits that I have which I cant identify. They may not be DT parts or indeed even Douglas parts. But if you or anyone else can identify any of them it would be a great help. Finally I have put aside the parts for engine 2 for now, although they are laid out incase I need to raid them!

The bottom end is a bit more of a worry to me, because the sort of work you describe is not something I am able to tackle. My experience and equipment are essentially drawn from tuning and building up post war car engines. New parts have generally been available for these and the UK still has a pool of expertise in machining such parts when needed. So I understand the need to do things properly, but not how to carry out some of the specialised jobs you mention!

I feel relatively confident that if I had a complete set of new component parts available I could, using your notes and my experience build up a DT crankshaft and conrod assembly. I'm far from being able to get those components though!!

On a happier note a chance discussion at the gym yesterday identified a local man who has "several Douglas'". My informant is in the same local branch of the VMCC as him, and is going to try and get me an introduction......
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Douglas Motorcycles - General Discussion / Re: DT/SW5 Engines
« Last post by Buzzie on 10 Jan 2019 at 20:23  »
Hi Doug

You were right to warn me of indigestion! I have read through your post, and decided to break it up a bit and think about my valve gear first, and move onto the bottom end later!

I have re examined my valve gear more carefully in the light of your remarks. They either must have had limited careful use or have been refurbished properly using similar techniques you described The rocker tubes are very close to being an interference fit. I certainly cant get a feeler gauge between the perches and the end of the tubes. The perches themselves are pretty much unmarked.

The rockers are a different issue. They are a motley collection. Two have been polished, one of which has been chromed, and two are unmolested. The cups are in good condition, but as I already mentioned the pads are all worn. They are a bit worn internally, but they don't generate a lot of play. I do have an extra rocker, but it is significantly worn around the axial hole and is polished and chromed.

All the valves on the first engine set up by the engine builders have double valve springs. The other engine only has single valve springs fitted. Its also likely that the springs are all pretty tired by now. The push rods seem to be fitted with double springs fitted, but they don't look very strong. Both engines have the same types of springs fitted.



I did find a cover that goes underneath the magneto which has the lifter rockers fitted, but no sign of the rest of the mechanism you pictured in any of the engine parts. As I will be starting the engine with a donkey engine turning the back wheels(jacked up off the ground) I was wondering if I would need the lifter mechaniasm?

At this point I should mention that it is most unlikely there is any cross pollination between the two engines. I bought the first one as a pile of bits in about 2000 from an LDMCC silent auction. There were many more parts than needed to build one engine, some parts that probably don't come from a DT engine and a few parts completely missing. The second engine was bought on Ebay in November. It had been fairly recently partially disassembled and was sold as complete. It is almost!!

I did find a cover that goes underneath the magneto which has the lifter rockers fitted, but no sign of the rest of the mechanism you pictured in any of the engine parts. As I will be starting the engine with a donkey engine turning the back wheels(jacked up off the ground) I was wondering if I would need the lifter mechaniasm?

Another little oddity I found was that two of the grease reservoirs have a little spigot split axially cast into them. I have about 10 ordinary ones in total, and these two odd men out. They seem identical in every other way to the others

The rocker gear etc in the other engine seems much more worn, although I haven't dismantled it from the head. So my plan is to bash on with engine 1 s valve gear in its current condition, with a view in due course to having a full refurbishment of the second set done for the second engine.

As posting pictures is still causing me problems I'm going to try and upload this section, and then post a second piece about the bottom end.
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Next phase of the Dragonfly switch replacement. A contact tab.

I need to make the contact tab that goes onto the switch mounting stud.
That is the one that would be contact number 9.
On the circular central switch area there are different contact bands.
Which of these should contact 9 bear against?
It presumably fits on the stud under the nut?
What shape should it be?
Like one of the other contact tabs?
Any help appreciated
Many thanks.
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Douglas Motorcycles and Parts For Sale - Private / Re: Mk5 parts for sale
« Last post by petee on 10 Jan 2019 at 18:13  »
Are the parts still for sale? many thanks, Pete.
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Douglas Motorcycles - General Discussion / Re: DT/SW5 Engines
« Last post by Buzzie on 10 Jan 2019 at 17:32  »
And  some of the pistons and my impression to measure the volume of the valve dome

Im sorry, but I cant upload any more pics, and I dont want to try again for fear of locking the thread again
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Douglas Motorcycles - General Discussion / Re: DT/SW5 Engines
« Last post by Buzzie on 10 Jan 2019 at 17:24  »
When we had the Forum issue a few days back I was unable to post some pics I mentioned, so here they are now.They are of my first engine:

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