Clutch adjustment (again)

[Sam C]

Sorry all - I suspect this topic has been covered a lot but I've researched this as much as possible before putting this up:

The other day my clutch cable weirdly stretched while in heavy traffic, meaning the clutch wouldn't disengage properly. Nightmare at traffic lights! I tightened the clutch when I got home using the adjuster on the handlebar, and it worked fine as a result, but this has left me wondering 'why'? It happened with the bike quite hot - if that's at all relevant.

I've got the longest trip of my life coming up this weekend and I've got two nights to prepare. Below is my theory and planned solution and I would really appreciate everyone's thoughts!

My current theory and solution is this:

Theory:

(a) When I last took the clutch apart (to reattach my cush drive nut that kept coming off!) I reassembled it 'just by eye' and may have over tightened the spring nuts. Mine's a four spring clutch (even though 1959 Golden Flash).

(b) I think this might have meant that, despite the fact that the clutch worked, there was too much pressure on the cable each time I disengaged the clutch. It was certainly quite hard work on my left hand. I wonder if this is what caused the cable to stretch when I was repeatedly using the clutch in heavy traffic.

Solution:

(a) Replace clutch cable.

(b) Get primary chain case off.

(c) Remove and check all clutch plates (i.e. flat, not a burnt colour, not pitted, not scored).

(d) Check not any play in the clutch basket etc. Also check that the nut that holds it on is ok i.e. not loose (I'm expecting this to be inside the clutch basket and with a tab washer on it).

(e) Check not undue 'notching' in the clutch basket (I.e. where plates ought to slide, but don't if there is notching).

(e) Critically: replace the clutch plates and use the 'tighten the clutch spring nuts just until the clutch stops slipping, then balance' technique which I've read about on here but never done before.

This seems to be:'run the bike with the front wheel up against the wall, start the engine, put in gear with clutch disengaged and then slowly re-engage'. It should stall and if so I'll loosen it until it starts to slip (when I repeat the procedure), then I'll tighten by about half a turn on each nut. Then I'll check the balance - using an improvised 'pointer' (piece of wire') turning the clutch over in neutral with the kick start. Then I'll repeat all over, until happy.

I expect the above procedure to ensure that I've not overtightened my spring nuts: so my cable is not under undue tension, and my left forearm doesn't end up like Popeye's!.

(f) I will then make sure that the clutch cable is appropriately tightened at the handlebar, so I've got a small amount of slack (as with all bikes).

Note: I don't plan to do anything with the adjuster that is down by your right foot, through a little inspection plate. Is that right?

(g) Finally: put the primary chain case back on and put some oil in. On that: Am I right in thinking the 'correct' amount of oil is 'just enough so the chain dips in it', and also that it's ok to use the same oil in the primary chain case as in the engine in general?

Thanks in advance all!

Sam

P.S. The Haynes says the clutch lever (down by right foot again) ought to be parallel with the bike when the clutch is fully disengaged. Mine is not. Is that important? I'd say mine could still travel about another 1.25 cm (1/2"). Could this be relevant to anything?

[Sam C]

Sorry all - that post is way too long!

[morris]

A four spring clutch should be declutchable by a one finger pull on the lever(at least mine is), so your theory about over-tightening it may be right. On mine I have still got at least one spring winding visible after adjusting.
None of that fancy stuff like Surflex plates, all standard setup
If the nut came loose, it might give the symptoms you described, although the lever action should have felt loose then.
Go through all the checks and be sure that you adjust it as square as possible, and it shouldn't give you any more trouble.
As oil I would recommend an hydraulic oil ISO 32 or, as some swear by, ATF fluid. I found mine very sticky with regular engine oil so went for the hydraulic oil.

[Triton Thrasher]

If the clutch now has end float, check the nut on the other end of the gearbox mainshaft, for tightness.

[Billybream]

Could the clutch pushrod have unhardened ends, if they are not hardened the ends will wear very quickly.

[beezermacc]

Hi. This is a common problem with A10 4-springs. I suspect you had a bit of drag on the plates so, when you were stationary, holding the bike on the clutch, the plates got hot and warped. As the plates buckle and warp they make the clutch bigger (because the plates aren't flat any more) and lift the pressure plate off the end of the clutch, consequently the pushrod doesn't reach into the pressure plate any more, so the clutch drags, and all this slack in the pushrod (which is essentially just an extension of the cable) is felt at the handle bar lever, giving the impression that the cable has stretched. When the bike cools down the problem mysteriously resolves itself....until next time in traffic! The problem is that the clutch lever / cable / actuating lever geometry doesn't create very much lift at the pressure plate so any slight unevenness in the pressure plate lift is going to cause friction amongst the plates, then the heat buckles the plates. It is essential to take the time and trouble to ensure the pressure plate is lifting evenly by spinning the clutch on the kickstart with the handlebar lever squeezed in, then balancing the lift with the spring tension. Most A10 owners have developed the habit of engaging neutral just before coming to rest so that it is not necessary to drag the clutch whilst stationary.

[mikeb]

Sam I'm pretty new to this stuff but did exactly what you said and mine worked (I probably reviewed the same posts as you too). so do that. and the other checks listed above

i did my b33 twice as the first time i used the piece of wire trick and didn't sufficiently account for the wobble in the basket of the horrid 6-spring. second time i used a dial gauge to ensure lift was as even as possible, just as beezermacc says. similar on my a10/4-spring

The problem is that the clutch lever / cable / actuating lever geometry doesn't create very much lift at the pressure plate

extending beerermac's idea, on the b33 i replaced the clutch lever from a 7/8 radius to a 1 1/8" radius (between pivot and cable end). this gives more lift between the clutch plates. on the b33 the change is much easier - on the 4-spring in wonder if the extra lift would help the disengagement that beezermacc emphasizes. anyone tried it on an a10? and if your springs are well set it should stay light on the wrist.

and the lever by the gearbox being out of parallel would suggest you have less travel than desirable (thinking trigonometry etc) - hopeful others can suggest why.
and yes re the oil level in the primary case (i use castrol 4T)

[duTch]

 

and the lever by the gearbox being out of parallel would suggest you have less travel than desirable (thinking trigonometry etc) - hopeful others can suggest why.

 I think another reason for being parallel is to minimize side-loading on the pushrod, obviously the main reason is to maximize travel.
 My aftermarket crappy hand lever is just over 28mm- close enough to 1-1/8", and I have about ~3mm/1/8" lift at the pressure-plate.

 (For what it's worth, and for the benefit of possible future enquirers) with regard to the six-springer, (which is completely different to the Plunger six-spring, but vaguely similar to a 4 spring), my Plunger six springer has some chainwheel wobble, but I concentrate on the pressure plate and do it by eye (holding hand lever in with special tool and turning rear wheel in 4th), and it seems to work ok.

[Sam C]

Thank you everyone.

Well, this is where I've got to:

(a) I couldn't get the clutch to slip - using the above method. It just wouldn't do it! Just kept stalling it instead, no matter how far out I undid the clutch nuts (within reason). I wonder if this was because I wiped down the plates so they were spotlessly clean (but therefore dry), before replacing them? On my dirt bike you're meant to soak the clutch plates in oil before replacing, but I didn't think that seemed right for this bike so I put them in dry. A mistake?

Anyway, I gave up trying to make them slip in the end and just balanced the clutch with the nuts out as far as I thought was safe, but no further (basically the tops of the nuts are level with the tops of the threaded studs). The clutch works, anyway, and its definitely balanced (or 'as balanced as possible' - maybe 2mm wobble).

(b) My plates were not warped. All flat and the friction plates had plenty left on them. I'm satisfied they're all fine. However, I'm mildly worried that the issue described above would mean that they only 'appear warped when hot' though - is that something to worry about?

(c) There was no 'in / out' play on the clutch basket / large sprocket that it is attached to. However there was some wobble 'side to side' (by which I mean if I hold either side of the sprocket in each hand I can move my left hand forward while I move my right hand back, and vice versa). This was maybe only a small amount (maybe 1/4" on each side). Is this a problem?

(d) My nut was firmly on!

(e) There was only a very tiny amount of wear in the clutch basket teeth (i.e. almost no 'notching'). I'm happy with that.

(f) I have appropriate slack at the clutch level (handlebar) and a tiny amount of free play at the clutch lever thing by your right foot. The clutch lever on the handle bar is perceptibly easier to use than it was before.

However, that lever down by my right foot is certainly not parallel with the bike when clutch is disengaged. I'm not sure how to do anything about that, still (without replacing it for a different sized one). Maybe I should start fiddling with the adjuster that is right next to it?

(g) There is oil in primary chain case now. I just went with standard motor oil. Just to the point where the chain just dips in it (and will presumably chuck it all over the place, including a small amount into the clutch plates - in which case maybe they'll start to slip and I'll have to start all over (!?)

Test ride tonight. I'll let you know how I get on. It was 23:00 by the time I left the garage and I was sweaty and knackered - so couldn't test it then!

I really appreciate all the helpful comments on this. Thanks again!

Cheers

Sam

[Butch (cb)]

Hmmmmm. So the clutch adjustment changed, was corrected by an adjustment to the cable and then it settled down OK again in the new position? Though you’ve since been in to inspect things.

If the cable has stretched I would expect it to continue to do so quite quickly until it failed. If the clutch pack expanded with heat I’d expect it all to return to original settings once cooled. I don’t think flat plates warp when they get hot, warped plates get more warped when they get hot. I’d be looking at the clutch rod, particularly the two ends, and for any other items that could have moved/slipped to produce a ‘one time’ change. 

[duTch]

However, that lever down by my right foot is certainly not parallel with the bike when clutch is disengaged. I'm not sure how to do anything about that, still (without replacing it for a different sized one). Maybe I should start fiddling with the adjuster that is right next to it?

  It is important if you don't want to wear things out prematurely, so probably a good idea to start fiddlng.  .... adjust the actuating arm on the box ("that lever down by my right foot ")  so it's parallel  with the inner/outer cover joint, that is done by removing the inspection cover below it and loosen the locknut, and screw the adjuster (out in your case) until the arm is in an ideal alignment (I personally split the difference between either side of parallel slightly favouring 'out'). **This reminds me that if that adjuster/arm is in the wrong position, the adjuster can interfere with the inspection cover, which in turn can slightly disengage the clutch and make it slip.**

 After doing ^that^, then adjust the cable nearby, ensuring when the actuating arm doesn't contact the adjuster when the hand lever is pulled in.

 ** and if you haven't done it already, check the condition of the cable at the top next to the lever nipple**

[chaterlea25]

Hi All,
Today a chap called on the B31 that I recently rebuilt the engine on, he fitted the engine himself
He was having difficulty engaging first gear at a stanstill and neutral coming to a halt
Anyway the clutch arm on the gearbox was far too far outwards (imagine 20 past 4 oclock)
I removed the gearbox cover and the threaded adjuster which was just about going to fall apart
the end of the pushrod was flared out too
I found a replacement adjuster and took out the pushrod cut it in two, fitted a roller bearing between the halves, before finalising the length so the adjuster and lever were in the correct position,
then rehardened the ends .
Of course the clutch cable was then "too long" so about 15mm was cut from the inner cable and resoldered the nipple
When we restarted the bike it easily selected first form stationary 

John

[beezermacc]

I don’t think flat plates warp when they get hot, warped plates get more warped when they get hot. 

The reason they warp is because they don't heat up evenly, they get hot patches. A couple of years ago we were heading out of Brighton in queueing traffic and my mate on his A10 suffered the slack clutch lever and dragging problem. We had to stop at the side of the road and wait for the bike to cool down. When we got home we stripped the clutch but could find no problems. We reassembled the clutch, took care with the spring tension and we've not had any problems since.

This problem does cure itself when the bike cools down so, if the clutch lever is still slack after cooling, the push rod has probably melted.

[duTch]

 I'm not by any means disputing any other suggestions, but something else that occurred to me is if the Actuating arm is that far out of whack I wondered if it's possible for it to be a tooth too far around on the spline, which may place the adjuster correctly, but place the arm too far out 

[Butch (cb)]

I don’t think flat plates warp when they get hot, warped plates get more warped when they get hot. 

The reason they warp is because they don't heat up evenly, they get hot patches. A couple of years ago we were heading out of Brighton in queueing traffic and my mate on his A10 suffered the slack clutch lever and dragging problem. We had to stop at the side of the road and wait for the bike to cool down. When we got home we stripped the clutch but could find no problems. We reassembled the clutch, took care with the spring tension and we've not had any problems since.

This problem does cure itself when the bike cools down so, if the clutch lever is still slack after cooling, the push rod has probably melted.

Different construction entirely I appreciate, but I once bought a Guzzi T3 with a very unpredictable bite point. It would be all over the place on the lever, and with increasing slack as it heated up. When I eventually got round to pulling it down (a fairly big job on these bikes) I found that the central plain plate could have doubled for a fruit bowl.