Clutch Adapter Differences

[chaterlea25]

Hi All,
I went through my bikes cush drive a week or 2 ago and took some measurements
The "space" for the spring when the SRM nut is fitted tight is 30mm app (1 3/16in).
The springs are 3 1/4 turns of 8mm so 26mm fully compressed
I bought a "new" spring but it has 3 3/4 turns so 30mm fully compressed, so it would be coil bound if fitted !!!
I could not put my hand on an original crank nut this evening but the dimension is on my original thread
Bagonail's photo shows a lot of thread protruding through the new nut which is a puzzle??
I cannot remember if BON's inside crank spacer has been measured or not?
If the chain line is good ? I would make a spacer to fit inside the nut but it must not interfere with movement of the sliding cam

John

[BagONails]

Thanks to all, I will take some more photos and make a sketch just to confirm all the sizes and also post these in the new cushty conumdrum thread.  From what I have seen so far it looks like the sliding sleeve may be the culprit in my case. Cheers.

[berger]

i knew this was here and i found it   these after market adaptors for the 4 spring clutch are crap! i have attached some photos showing the same problem BagONails came across. not only the chain alignment but also the position of the oil slinger to the felt pad plate. even if i space out my crank  sleeve to get the chain in line the oil slinger will still have the gap for oil to leek from. there are also photo's showing an original BSA 6 spring clutch centre on the berger build gearbox shaft and on a spare rrt2 shaft. both shafts get the same result with the clutch centres. 

[berger]

BagONails when you sorted yours didn't you think to make a plug so as to leave it in the 4 jaw and save time keep setting it up.

[BagONails]

BagONails when you sorted yours didn't you think to make a plug so as to leave it in the 4 jaw and save time keep setting it up.

No I didn't did I! Could'a, should'a, would'a  but too wrapped up in the heat of the moment I guess.  Always pays to sit back and have another think aye, but it all worked out well in the end.  Still running well and after 3 years of regular club runs etc I've not even had to readjust the new primary drive chain yet so I think running in oil instead of dry and getting things lined up was well worth the effort!

Sorry to hear you've suffered the same issue Bergs did you buy from Feked too?

I had a load of problems at the cushty drive end too of course. Again the reduced cush travel I ended up with doesn't seem to be causing any problems although I do drive the old girl pretty gently, or should I say appropriately, mainly due to the terrible brakes 

On the plus side it looks like you should have room in there to make a proper seal and holder on the sliding plate instead of that joke bit of felt?

[Colsbeeza]

Bon, When I first ran my bike, the chaincase leaked like a seive from the clutch adapter. The felt seal was fairly useless. I put another felt seal behind the adapter like SRM sell, and it seals very well. After a hot run, I may get a couple of drips on the floor, but nothing major. The sliding plate stops the felt rotating, and it seals on the back of the adapter. I used 6mm felt, but had to grind it down to a sensible thickness. I think SRM's are about 3mm. Some have machined the sliding plate to hold a proper seal, but I think that is a bit of overkill.
Col

[BagONails]

Hi Col, yes this has been discussed many times but I think the key is not to overfill the primary. I only put enough in to JUST wet the chain on the lower run going around the chainwheel. My dodgy bit of felt doesn't leak either and my (4 spring) clutch is great, never sticks or drags. (SRM plates and pressure plate, new springs) This works out to be somewhat less oil than the recommended amount but it works for me. The chain is always oily and as I said I haven't needed to touch it since it went in. The oil is still quite clean too, its been changed once and the case wiped out last year as there was the initial expected running in detritus but its all settled down very well. I use Nulon 10W40 modern day engine oil to JASO standard, OK for wet clutches.

[berger]

BagONails yesssss freeking feked, i only found out by trial and error that it wouldn't sit far enough on the gearbox shaft not only to line the chain up but to also just enter the sliding plate so the oil thrower wouldn't have that gap. i wonder if they were ground on the cautious side because too far in and the oil thrower part would but up to nut on the drive sprocket. it is twice as long as the standard oil thrower on the BSA  6 spring clutch.

[berger]

after visiting 2 very good engineering workshops both  in a radius of 5 mile from my house not one of them has the means to grind out the adaptor, but one of them put me onto another hidden workshop that sits behind chesterfield motorcycle shop and i never knew it existed , it turned out to be an old mate who i grew up with but haven't seen since we were 20 years old.  he has massive cnc machines  , big lathes , millers and all sorts of massive machines in a massive unit. he remembered me and mentioned my dad who made him parts when he was 16 years old. the problem was he couldn't do it either BUT he put me onto two firms in sheffield who he uses for grinding and they are only 14 miles from me. i phoned one up and it looks like they can help me out so i will be taking it to them this week 

[BagONails]

Hey Bergs, Aaahh Nooooooo, you've been feckin feked mate!

Dear oh dear, never mind.

Reading back through the thread I remembered I found the taper as well as being undersize, didn't match my mainshaft taper either. Nominally 4 deg's.

Have you blued your old and new parts up to see what the fit to the taper is like?  If you are going to use an old part as a pattern then it would pay to be sure it is correct first?  Equally if you can give your engineery old mate your gearbox then he can check and grind the adaptor to suit which would be best.

I'm feeling pretty good about my own rework on this part now on a little old early 60's Italian lathe (a SAIMP 340x800)  with cheapo Chinese boring bar and tungsten insert. Did the job and we got a fine finish which needed only minimal lapping to achieve a near perfect result.

Perhaps you should discuss the job with MWAS Bergs or has he said Worty's rebuild was it for him - Just the mention of BSA now is enough to trigger a severe PTSD and panic attack!

[berger]

BagONails , haha i have been to MWAS and he had a dicky fit, something about his tool post grinder still needing work done and setting it all up. he had a dicky when i asked him to mill out a bit more gap on a side stand i have. the problems are he is full on with several howard garden diggers for himself and to sell on plus misters from the allotments keep giving him those LITTLE jobs that will only take 10 minutes , he's just finished re cutting the splines on a big gearbox shaft that was twisted so he weldered it up and machined it back to std. he is  also in the process of smashing up all the old concrete floors in his house because they are full of damp. up to now he has got his living room sorted and a small room he uses the most, all damp proofed and plastered out. i have been blueing the job a few days ago and i'm satisfied the dummy shaft will be ok for the grinder to work to . thanks for your input   freaking feeked yes maybe they had them done on knackered grindle stone

[berger]

Colsbeezer i am reading your post as to say the felt is rubbing on the scroll at the back because it's thicker and with a smaller diameter hole. this means if yours was leaking you may have the same problem i came across with the scroll not entering the brass collar and the felt pad just butting up to it stopping some of the oil leaking? ... first pic is a slight over kill of how much gap there is , second pic shows it just about entering the brass collar and it would leak badly if left like this. did your chain line up ok ?

[Worty]

I will not tell anyone what happened with my clutch centre and how I fixed it because there are some on the Forum that may have certain health problems and I don't want to be responsible for any subsequent hospital admissions.

[berger]

well what a disappointing visit to a mahoosive shed of machines that was,  a traffic jam of 2 miles long going and the same coming back home, it's called lets DIG! . i took the clutch centre to the grinders and when i walked through the door the first thing that hit me was the heat and smell. On looking round the place and seeing a few men sat at BIGGG machines i thought these people know what they're doing. A man in the office upstairs beckoned me in and i explained what i needed doing. we both went down to see his foreman and it was a definite NO! .. i have now been in contact with another grinding firm in Sheffield and they now have pictures of the part and will let me know next week.

[Worty]

Why the 'no' Bergs?  Surely any firm that does grinding could tackle the job?  Maybe not worth their time?