revtothelimit - motorbike forum

You should know when you’re riding a bike with a slipping clutch.

Aye....but when it also backfires and misfires too....

Plus I must have been quite a bit down on power judging from the previous state of the bores.

I used to stick my old Enfields plates in a pan with water and boil them for ten minutes.

Slippping clutch cured, kitchen stinky, subsequent mashed potato oily, flatmates not happy.

From poking around tonight I appear to have discovered that the woodruff key (22) is broken...the clutch centre (6) is able to spin when it shouldn't.

So its not just a case of clutch slipping. Its a case of "clutch not actually connected properly".

Love the cush drive in the clutch.

The woodruff key should just be for positioning, something else should stop it spinning, possibly a tapered shaft.

Yep. Woodruff and Morse. Which is why it "sorta" works.

I used to buy a woodruff key every other week for my GP100.

So is the shaft taper damaged?

Dunno yet....still getting my head around im supposed to get it apart.

I've got the extractor tool (the one with the thread on the outside and a bolt thought the middle) and I know I'm supposed to give something a clout and be ready to catch some rollers

The extractor is for breaking the grip of the taper.

You’re saying it has already lost that grip.

Yeah I probably am, but it also doesn't spin completely free. With the bike in gear and the rear wheel stopped it can turn maybe plus minus ten degrees. Need to get it apart and have a look.

I think you will find some interesting marks on the taper. ..

Hoping I can lap the two together again, assuming that this is the problem....

Otherwise fuck knows how I'll fix it.

Mr. Dazzle wrote: Mon Aug 02, 2021 8:26 am Hoping I can lap the two together again, assuming that this is the problem....

Otherwise fuck knows how I'll fix it.

I'm assuming there's experts you can pay, I know people like Alan millyard specialise in these. He can't be the only one

Well yes, that's the obvious solution.

The head was repaired and the cylinders we're re-honed by this guy, he's just down the road from me. His shop has about a dozen lovely looking 'black and silver' bikes whenever I go there and he spanners for a BSB team, so I assume he knows what he's doing. He did a lovely job on the head.

https://vintageclassicmotorcycles.co.uk

I'm under no illusions that it can be fixed, it's just a question of how difficult/expensive it'll be.

Lapping the taper in with valve grinding paste usually fixes it.

Otherwise, I’m sure it’s not a difficult job on a lathe.

If I remember right, from the last time I had gearbox trouble, the mainshaft can be pulled straight out of the cluster, towards the timing (right hand) side, once the gearbox inner cover is off. It can also be pushed straight back in, without disturbing anything.

The morse taper with right-hand threaded nut on the clutch hub is shoddy. Dave Nourish used to make splined ones for racers. I get a trouble-free primary transmission by Loctiting everything that has splines, threads or keyway.

The various tab washers don’t keep the nuts tight: they just stop the nuts falling right off after they’ve come loose. Loctite is needed.

Yeah grinding a taper I'm OK with. It's getting the shaft out of the bike and into a machine which worries me

Mr. Dazzle wrote: Mon Aug 02, 2021 10:15 am Yeah grinding a taper I'm OK with. It's getting the shaft out of the bike and into a machine which worries me

Lapping the taper in should do it, you don't need to remove the shaft to do this.
If you need to get the gear shaft out it won't be difficult, just time consuming, it's a Triumph, it was built on pre war lathes in Birmingham.

Le_Fromage_Grande wrote: Mon Aug 02, 2021 10:44 am it was built on pre war lathes in Birmingham.

You'd never be able to guess