CL008 CLUTCH

I've spent today trying to obviate clutch drag. I'm sure that you're familiar with the problem; I can only eliminate it adequately when there really is only minimum play on the cable at the lever end - a bare 1/8inch. If I leave any less than this amount, I get slip and don't want to run the risk of pre-loading the thrust bearing assembly. Frankly, I've found this assessment of free play very difficult; my guide has been that the nipple is free to move within the blade. I guess I'll have to accept a bit of drag and use neutral as often as possible.
Are there any particular tips or tricks in setting up the clutch? I've been going exactly by the book; I'm more than familiar with the procedure "as writ" now, it's just the results that are a bit disappointing. Martin Arscott of Tring, who rebuilt the motor, carb, magneto (BTH manual), gearbox and clutch, certified in the notes which I got with the bike that the clutch was OK - in rebuilding it, he had replaced only the n/s bearing with a roller one. So I'm assuming that the mechanics are basically sound and that a bit of drag is inherent in a design which employs the very minimum of plate separation. Is this the general experience?
I suppose the long term solution would be to go for a set of the updated plates and chainwheel offered by the club - but having just bought the bike, and a new Lucas dynamo and regulator to replace the 36W Miller toy, my chancellor would reasonable frown upon such a suggestion, at least for the moment!
Generally, I'm very pleased with my purchase. Apart from the mechanical rebuild referred to above, the previous owner did a lot of work to it. The frame and tinware have been professionally stripped and repainted. New shocks, stainless rims and spokes,tyres, chains, wiring, exhaust and silencer, quite a bit of re-plating. I wanted something a bit simpler than my Rocket 3, but having spent so much tome on the clutch/primary transmission, I've concluded that I have bought something different, rather than simpler! - Roger Hinton 17/3/2002

It's worth persevering with the clutch.
A good one is very nice - light & smooth and doesn't drag or slip. It makes a big difference to enjoying the bike.
The clutch design was fine, it just has to be set up right with totally flat plain plates. The Velo specialist dealers used to rub them flat on a flat plate - that's how flat they need to be.
You'll see the other Q&As cover several points, but the main things in them you should check are:
You have a clutch lever with the required extra throw for a Velo.
You don't have a 20 spring clutch holder, or if you do you take 4 springs out for a standard Venom. If a Thruxton, you will need 20, so have to put even more effort into the things below:
The sleeve gear nut is dead tight, otherwise you lose motion in the operation of the clutch as it wobbles; likewise the sleeve gear bearing lock ring must be dead tight and punch locked - if it comes loose it causes damage as well. But I think you can assume MA would have tightened these OK. Similarly, the pivot for the thrust race operating 'frying pan' has to be shimmed so it is parallel at mid-lift - again MA would have done so.
The clutch cable must not lose motion by having a stretched outer, such that its coils compress as you operate the lever; nor must the cable be trapped by anything so it is held a little off the tower stop until the lever is operated.
But the main problem is usually warped plain plates (possibly only when hot), and since it only costs £15 to replace all these with the club's non-warping ones it is worth doing first just to eliminate this possible cause.
Clutches do bed down a little, so give it a thousand miles by when it may not slip so easily and motion may not be lost in various components not yet bedded in.
After all that - just modify the clutch lever to give more throw. And if you have a roller thrust race then don't worry too much about pre-loading it to give you full throw. I used to have to use 20 springs and other dodges on my Venoms to prevent slip, so always pre-loaded the thrust race slightly, reasoning that it was cheap enough to replace and if that meant a major difference in riding enjoyment - so be it! - TW 17/3/2002

I will persevere. I guess that more experimentation is called for! Can I try you with a couple more questions? My main problem is drag. The centres of the lever pivot and nipple are, incidentally, 1.1inches apart.
As it appears to me, in order to reduce drag I could screw the spring holder in fractionally, but slip isn't far away! The alternative, which I wouldn't want to pursue with a plain thrust bearing, but may be possible since I have roller bearing, would appear to be to:
a) screw the spring holder out from the "just slipping" point until I have the necessary 1/8 inch free play at the lever end, as per step 4 of the "drill", then
b) use the cable adjuster to reduce play at the handlebar lever a bit, thereby increasing throw, albeit that there may be a light load on the roller thrust bearing.
Am I understanding it correctly? Is this the way to go about it? I know that the book is quite clear about forgetting the cable adjuster option, but is it open to me with a roller bearing?
Am I making sense here?!! This is foreign territory and I may be getting it very wrong!!
Finally, you mentioned modifying the clutch lever to increase the throw. Did you mean, quite literally a physical mod? What did you have in mind? RH

I would do, indeed do do, just what you suggest when diagnosing or tolerating a dragging clutch.
I make quite sure that with the cable completely loose there isn't a trace of slip on the kickstarter (otherwise starting will be difficult).
Then I take up all the slack in the cable short of causing the kickstarter to slip.
Then as soon as it's started I overtighten the cable so as to get more movement. Yes I'm preloading the thrust race, but if it cures drag and doesn't slip in use (except for kickstarting, when I release the cable again if necessary) then so what - I might need to replace the bearing in 10,000 miles but then I'd put a roller one in. They are both cheap.
I have alloy levers with built in adjusters on both of my 20 spring bikes, so I can do it all on the move.
You have to be careful not to overdo it and push the frying pan out too much, but if you adjust the clutch first using the drill that shouldn't happen.
Yes I meant physically modify the lever - if alloy, I remove metal so it has more travel until my hand can only just reach the blade, if steel then put a blow torch on and bend the blade out so it takes longer to hit the bars (Though it will now be blue/black) - Ralph Seymour first recommended that to me! (Or let the bike fall off its stand onto its left handlebar - I found that out very early, along with everyone else who's crashed a british bike.) - TW

I have persevered with the clutch set-up on my Venom and reckon that I'm just about there now, the clutch neither drags nor slips and I have about one eighth of an inch free cable movement at the lever. What a difference. But my earlier omission to spot an obvious problem should be a lesson to others.
I was experiencing continuing frustration with clutch drag. After following your advice, things had greatly improved but I was still left with a bit of drag which was evading all my efforts. Then I noticed, almost absent-mindedly, that the L/H twistgrip rubber, though apparently secure, had loosened and slipped about one quarter of an inch towards the end of the bar. Now the rubber ridge on the outer end of the grip aligned nicely with the end of the clutch lever when it was pulled in. So what? Well, my clutch lever has a ball end!! The coming together of ball and rubber ridge was restricting lever movement! So - reposition rubber, secure it properly and Voila! Clutch drag disappears!
I've never seen that one mentioned in the books! Absolutely obvious with hindsight, but not obvious when you're mindset is committed to solving more complex problems. At the risk of exposing my stupidity, I pass this on as an object lesson in the need to consider ALL possible options when diagnosing a problem. - RH