Four Spring Clutch Wobble

[A10Boy]

I removed the primary chaincase to fit a SRM cush drive nut, and when I checked the chain and Clutch, I could feel a wobble on the chainwheel. The clutch pressure plate and centre remains still but there is play on the chainwheel.

The clutch works perfectly, so before i take it apart I thought i would ask if this is normal on the four spring clutch.

Any thoughts?

[A10Boy]

I took the plates out and there is noticable movement on the chainwheel, I looked at the exploded view in the parts book and I think its wear in the clutch centre - roller - chainwheel area. The question is, does anyone have experience of what wears, is it the clutch centre and rollers or is it the chainwheel as well [I hope not].

I will take the chainwheel off in the next few days and check the wear. I know the centre and rollers are available, not sure about the chainwheel though. a few phone calls in the morning will sort it.

[dpaddock]

"Wobble" is normal; it's the amount that matters. An eighth inch or so is OK with the 4-spring clutch as long as the chainwheel runs true.

David

[A10Boy]

David
Thanks for that advice. I measured the play and it is only about an eighth, also I picked up some new rollers from C&D today and will fit them while the clutch is apart then monitor it every few hundred miles.

[A10Boy]

An update for those who are interested.

I removed the centre nut and "basket", the hardened insert and rollers had jambed up - and the chainwheel was turning on the insert! My guess is that a previous owner had tightened it and not realised it had tightened up and the chainwheel insert came loose with use.

So off to Vale Onslows for a new chainwheel, fitted it and new rollers and guess what, the clutch tightens up when I do the centre nut up! Aaarrgghh. The rollers and chainwheel measure the same as original, so it looks like i might need to try a new basket and clutch centre, but before that does anyone know which is most likely to be out of tolerance ? I tried the chainwheel without the rollers and it still tightens up, and it looks like its only a few thou.

Any advice will be gratefully received.

BTW I bought a clutch locking tool with handle from Empire Spares on ebay, its a great bit of kit and only about 12 quid.

[Brian]

Not sure if it applies in your case but it is very common for people to get caught with the rollers. They are 1/4" in diameter but only 6mm long. If you put 1/4"x1/4" rollers in when you do the nut up it will lock the clutch. Most specialist BSA dealers have the correct rollers, I got mine from C@D's.

[flashblack]

One thing you might want to check is the dimensions of the clutch centre, i say this because i recently had the same problem as you which was due to a clutch centre i bought twenty years ago when i first put a triumph type clutch on. At that time there was a large batch of centres thad had been made wrong, consequently when you bought one you were also sold a set of rollers made undersize (width not diameter) to compensate. Of course, years later i replace the rollers with new ones, altogether forgetting about the undersize rollers, hence the problem. In fact, i only found out when i took my old centre in to compare to a new one,  then my memory clicked .. eventually.
 If you need any measurements off the wrongly made centre for comparison i would be happy to dig it out and measure it for you,
                            Richie   

[A10Boy]

You were right Richie. I took the centre to Vale Onslow's and compared it to a new one, there was about 20 thou diference. It was enough to clamp the chainwheel to the centre which is what happened to mine, the chainwheel was turning on the hardened insert not the bearing hence the excessive play!

So I've got a new centre, chainwheel, plates and primary chain running on ATF. Fitted it back together today and went for a 25 mile blast in the sunshine, it works perfectly. Dont even leak !

[Servodyne]

Hi all,
Just picking up on this thread to add my experience.
When I built my Spitfire, it had one of the 4 spring clutch conversions supplied by JB restorations. It was made in England and the quality looked very nice, but there was quite a wobble when it was assembled. Probably about 1/8 inch on the clutch basket as previously mentioned. As there wasn't much I could do about it I carried on and ran the bike. The clutch worked faultlessly with a very light action for just over 1700 miles, until the primary chain broke. On examination it had broken in two places including the split link which I suspect let go first. As the chain was made by Regina, I wouldn't have thought this was the culprit so I checked the sprocket alignment and it was still good.
The teeth on the clutch basket had been damaged so I started looking for a new one only to find out there are two types out there. One has a rebate on the back face, like the one I had fitted and the other, made by Harris doesn't. The rebate is only 8 thou deep, but it could contribute to the effective end float of the basket and consequently the wobble. I bought the Harris version and presto, the clutch basket wobble was significantly reduced. With new Reynolds chain fitted, it confirmed that an over tight chain had not been the cause of the breakage, as the tension was still within adjustment even though the gearbox had remained untouched.
Hopefully, I'll have no more issues.
Jim