classic motorcycle forum
Motorcycle Discussions => British Bikes => Topic started by: mossy on November 20, 2017, 05:10:35 PM
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hi guys, this engine overhaul is still giving me loads of problems.i have began work on the clutch and having got the new cluth spring nuts I,ve found that they are fractionately smaller than than the studs on mine.it is clear that the clutch has been changed at some time as this is nothing like the c15 clutch seen in all the manuals etc. my chainwheel has 40-3204 stamped on the back of it,and although it is still a 4 plate and fits on the shaft/keyway o.k however there is a wobble/play so probably needs needs new rollers but I hav,nt a clue how to strip it down any further. I thought about re tapping the studs to fit my spring nuts but can,t get at them.i know its a long shot but if anyone recognises the number stamped on the back of it or knows what this clutch maybe off,then maybe I can progress further.any help would be appreciated,kind regards, steve.
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That's the part number for a C15 chainwheel so no problem there.
Most have "wobble" so don't go buying new rollers on the strength of that little diagnosis, and I wouldn't worry about "retapping" anything as if your diagnosis is correct then the studs would need changing and they won't be able to be "retapped".
IF I was you I'd ascertain what thread and type of clutch nuts you need and buy some, closely followed by a manual and a clutch puller.
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thanks rex,i,ll try that.(I already have both Haynes workshop manual and Rupert ratio book along with clutch puller.
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If you "haven't a clue how to strip it down further" then read the manual. ::)
Haynes aren't wonderful, but even that little book of words must detail how to remove the plates and use the puller, surely?
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cheers mate, I have already pulled the clutch off and ,removed the plates,but my clutch doesn,t look anything like the books. the backplate with the studs maybe has been replaced at some time as this is what the clutch spring nuts screw onto. i still hav,nt found how to get into it and the books don,t help much !
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Hi Mossy
Can you post some photos?
One pic is worth a thousand words
John
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thanks john i.ll get on it hopefully later today.regards steve
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hi john, right, I,ve stared at it some more and read the manuals. I,ve removed the four countersunk screws and then it says prize off the retaining plate. that's the bit I,m stuck on . how the heck do I get the plate off? bearing in mind I don,t want to damage the studs.. I know its probably been on for 50+years but it feels like its welded on !
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That plate covers the shock absorber, which is a vane type thing with rubber buffers. It actually looks like a Triumph clutch to me* although I'm not sure why you feel you need to remove the plate. It only really needs to come off if you're replacing the rubbers (which can be tricky.....)
The studs will probably be riveted into the backplate.
I'd look for the correct clutch as the taper on this one may well be incorrect for your gearbox shaft.
*not being an expert on either C15 or Triumph clutches........
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As Ian says, there's no need to remove this plate at this stage, but you should be able to screw in the clutch puller now and remove it.
I agree that it looks like a Triumph clutch (maybe that's why you can't use the puller?) but I've never heard of using a Triumph clutch on a C15/B40 before. I'm guessing the taper must be suitable as if not the clutch wouldn't be attached if not.
If I remember correctly the studs aren't riveted, but push through from the back and are prevented from turning by the square heads they have bearing on the rear boss of the chain wheel.
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Hi Mossy,
OK
So we need another photo of the rear view
Smaller resolution would help too
BSA and Triumph clutches look more or less the same in photos
The inner drum should revolve in the outer drum
It should push out easily from the back and drop the rollers everywhere :o ::)
Try an ordinary 1/4 x26tpi nut on the spring studs, if it fits ok then its the new spring nuts are the problem
Some of these type clutches the spring studs thread into the inner drum rear and are peened over at the back
These are one use only parts
John
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rex, you keep saying about not being able to use the clutch puller, i can, and have used the puller.i need to get this plate off, because my 1st problem is that the standard clutch spring nuts supplied don,t fit my studs so i think i,ve got to either retap the studs, which i can,t get to, or retap the nuts to fit my studs.either way i need to check both the rubbers and rollers,because the wobble or play is massive and while i,ve got it stripped down i,d like to remedy it. thanks for all the help and advice so far, cheers guys. i,ll also try and post another picture.
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When you say it wobbles, what exactly is wobbling? If it's the whole assembly on the gearbox shaft then it's probably the wrong taper.
Getting that plate off will not do anything as regards your puller. As John says the centre should just push out.
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When you say it wobbles, what exactly is wobbling? If it's the whole assembly on the gearbox shaft then it's probably the wrong taper.
I'm assuming that this "wobble" is the normal play seen at the chainwheel when the plates and springs are removed. If the wobble was due to the wrong taper then he'd be able to lift off the assembly as the taper wouldn't have grabbed.
In the pics the clutch assembly (or most of it) is shown still fitted, so how have you used the puller?
If you had, you'd have all the bits off and laid out on the bench by now?
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U guys need new glasses ?, I can see the mainshaft in the background and clear through the clutch centre, which is obviously removed from its shaft !!
I think the OP is on about the clutch centre rocking on its bearings on the clutch backing plate.
This is normally not an issue - once all assembled, the movement is quite limited (?).
Get the little cover plate off, and see that all is well inside ?
Then concentrate on getting the clutch assembled and working.
Your jar of misc nuts should let you figure out what thread is on those spring studs,
maybe you need to then buy something to match if you don't have them ?
Modifying them is usually a bodgers path to trouble....
hopethishelps.
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You're dead right R!
Only saw it when I expanded the image. Sorry Mossy for not looking more closely.
Now, what was the problem again?
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thanks,that helps very much,i have had it on and off the shaft a few times, there is a big wobble and I agree it seems to be be the centre rocking on the bearings, but when you say it will be less when its all put back together the wobble is still quite big even with the clutch plates and springs are fitted.that is when my problem started cos I have broken one of the clutch spring nuts and a couple of the others are a bit iffy. so I ordered new clutch spring nuts on line.these are the ones that don,t fit,but I am assured by the seller that these are standard threads.so if I need a new backplate I need to get it apart and that's the bit I,m stuck on.while its on the bench I need to sort it out properly before the engine goes back into the bike.how do you get the plate off the front when the four countersunk screws have been removed.( when I have got it off I will probably take it to a proper b.s.a. supplier to get the correct parts),cheers guys.it is a retirement project so although its sometimes frustrating it is also still a great deal of fun !
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With the clutches I'm familiar with (mainly Norton) there is nothing actually holding the backplate to the central drum - if there was it wouldn't rotate. However, the plate that holds the adjusting screws is wider than the hole in the drum so it won't come through forwards. It acts as a retainer for the rollers. What holds it all together are the adjusting screws in their cups clamping the plates to the drum.
So I would support the outer drum somewhere solid with a gap big enough to take the centre and backplate , put a solid bit of MDF over the protruding studs, and give it a firm whack with a ball pein hammer. This may of course only make matters worse......
Do you have a photo of the back of the clutch to show how those studs are held in? As has been said, often riveted over.
Getting that front plate off is unlikely to move you much further TBH.