Kickstart slipping... sprag clutch?

[BultacoBen]

My thoughts on reading the clutch adjustment instructions:

"...adjust the clutch cable so that there's 1/8" free-play, eyy...? Didn't I just take all the slack out of that cable!?"

Apologies for all the excitement folks, but many thanks for your fast responses! Problem now resolved and kickstarter engaging with engine wonderfully. Off to MOT tomorrow!


As an aside, my assumption of a sprag clutch comes from experience with modern motorcycles where many use one to connect starter motor to engine.

[gilburton]

You are correct in that a lot of modern bikes use a sprag clutch to engage the starter. I've just had the "fun" of changing one on an Aprilia Pegaso and my cn250 scooter has one.
It's like a bearing but instead of rollers they are shaped so that they engage one way only purely by friction.

British bikes have a kickstarter pawl which,as said, engages with teeth one way.
It needs the bikes clutch to transmit the movement to the engine ie you are turning the engine through the gearbox/clutch/primary chain to get it started so it stands to reason if the clutch is in poor condition or is slipping the kickstart will slip as well.
Usual bodge was to tighten up the clutch plate springs instead of buying new plates when we were young and had no money/sense

[clive]

.....
Usual bodge was to tighten up the clutch plate springs instead of buying new plates when we were young and had no money/sense

Good to know I am still young

[Janet]

if the clutch is in poor condition or is slipping the kickstart will slip as well.
Usual bodge was to tighten up the clutch plate springs instead of buying new plates when we were young and had no money/sense

How embarrassing, I thought that's what the screws were for.

[BultacoBen]

Further success! Bike rode (mostly) wonderfully down to the MOT station, where it may have failed, but failed in a good way...

That being a leaky fuel tank that only reared it's ugly head the first time I brimmed the tank on my way to the test.

All in all, I'm very happy!

Felt amazing to ride the bike through Bristol, and once I had the confidence of an MOT failed only for a leaky tank behind me and a bit more faith in the stopping power of the brakes it proved itself to be a bit of a hooligan bike... Very wide bars and only slightly baffled exhaust contributing here I'm sure.

Leak is mainly down a small trickle from the front fixing bolts, I think they may have been forced too deep at some point so I'll see if some PTFE tape can help resolve that. Also from the cap itself which I hadn't noticed is missing its cork washer. Clutch was slipping very slightly even with the cable adjusted correctly so it looks like I'll be following your advice on washing the clutch plates anyway.

Retest Friday.

[clanger9]

Good result! Always feels so much better once you've taken it down the road. Mine popped and farted all the way to the MOT and back, but it felt like a massive step just to get it on the road again....

On the clutch adjustment: the manual isn't super-clear, but you need to adjust both ends.
1. Back off the cable adjuster completely at the handlebar.
2. At the clutch end, remove the clutch cover screw on the primary drive case, release the locknut and gently screw in the adjuster until it just touches. Then back it off slightly and do up the locknut.
3. You can check the free play is correct by removing the gearbox oil filler plate - you can see the clutch operating lever, just check here for 1/8" or so free play.
4. Now do up the cable adjuster at the handlebar end to remove most (but not all) of the free play.

If it still slips, a strip & clean of the clutch plates is next on the list...