The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: RogerSB on 07.11. 2017 23:03
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Last week, along with other planned maintenance jobs, I removed and checked my 1960 Golden Flash's 6-spring clutch plates, refitted them and adjusted the clutch. It took a couple of hours to adjust the clutch to my satisfaction and afterwards I made notes of the sequence I followed to aid me at another time.
I anybody wants to read through it and can see anything I've missed or done wrong I'd be only too happy for them to point it out.
6-spring clutch routine maintenance:-
1. Slacken off the handlebar lever and the gearbox actuating arm adjuster.
2. After removing the pressure plate remove and inspect all plates and file off any wear burrs on the metal driven plates.
3. Pull out and inspect the pushrod and refit if ok.
4. Refit the clutch plates, metal driven plate first followed alternatively by friction and driven.
5. Fit the pressure plate after putting a blob of grease on pushrod bearing inside.
6. Fit spring cups followed by springs (new are 28mm long).
7. Mark a dot on edge of ends of studs to be able to notice if any rotate while tightening the nuts.
8. Screw on nuts so that they are just touching the springs.
9. Mark each nut with a dot to correspond to the dot on its stud to aid counting turns.
10. Tighten nuts alternating from one side to the other for 6 complete turns.
11. Mark numbers 1 to 4 on pressure plate at 12, 3, 6, & 9 o’clock.
12. Pull and tie the handlebar clutch lever in fully with a rope using a clove hitch.
13. Using a bent wire with one end wedged with a matchstick in a convenient bolt hole in the case, arrange the other end so that it just touches the outside edge of the pressure plate.
14. Remove spark plugs and select 4th gear.
15. Rotate the back wheel while watching the relationship between the end of the wire gauge and the pressure plate as it rotates.
16. Note any run-out discrepancies by referring to the numbers marked on the pressure plate and adjust.
17. Either screw in or out the nut near the run-out and do the opposite to the nut opposite it as required. This reduces run-out whilst keeping the pressure constant.
18. Keep doing this until the pressure plate is running true to the gauge all the way around its circumference.
19. Fit and tighten the lock nuts.
20. Release the handlebar clutch lever.
21. Ensure the clutch cable is slack and adjust the actuating arm on the gearbox by the adjuster inside the oval cover on the gearbox cover so that when the clutch is engaged (i.e. handlebar lever not pulled in) there is a little free play between the ball bearing embedded within the adjuster and the end of the pushrod.
22. Adjust the cable so that there is 1/8” of free play at the handlebar lever.
NOTE:-
If the adjuster’s lock nut and the actuating arm are positioned correctly on the mechanisms spline so they are in line with each other (parallel) then the lever will be parallel to the joint on the gearbox cover and more importantly the adjuster will be at a right angle to the pushrod when the handlebar lever is pulled in to disengage the clutch and there will be minimum side thrust imposed on the end of the pushrod and the ball bearing in the adjuster.
If the actuating arm and the adjuster are not dead in line on the spline, either slightly too much or slightly too little either way, the alignment of the actuating arm to the gearbox cover joint will be correspondingly different when the handlebar lever is pulled in and the clutch is disengaged.
My Golden Flash’s actuating arm is fitted on the spline incorrectly so it angles slightly more in towards the cover joint than the adjuster’s lock nut (so not parallel with it), which means that with the handlebar lever pulled in and the clutch disengaged it will be less than 90 degrees to the gearbox cover joint. However, the adjuster itself can be adjusted to be at a right angle to the pushrod and will therefore be in the correct position to apply force squarely to the end of the pushrod.
Amen!
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Sounds reasonable, but (unless I've had a brain-fart) no real need to remove the spark plugs
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A clove hitch, really? Fhtt! Maybe a constrictor or pile hitch, but never a clove hitch!
Uhhhh, on a seious note, many here use a dial indicator against the pressure plate.
Richard L.
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Hi guys, a couple of half hitches has always worked for me, cheers
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It's great to see this sort of advice, it takes ages to write out a post like this!
One small point, I use a dial gauge, and measure the actual movement at each of the 4 points. This removes the inaccuracy from any "run out" (wobble) of the clutch. The movement of the plate I get, from memory, is something like 080" (two revolutions of my dial gauge).
On my bike there is something like 020" wobble (I guess this will not be the case on all bikes) so if I did not measure actual pressure plate movement, after adjustment the outer plate would move 060" on one side, and 080" on the side opposite. Doing it the way I do I get an equal 080" movement +/- 010" on all 4 measuring points.
I can easily find neutral at a stand still on my bike after over 7000 miles without re-adjusting the springs, I have had to back off the cable adjuster a bit in that time though (clutch started slipping), I guess because the friction plates are wearing thinner.
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While I do basically the same, after squaring the lift, I back off each spring an identical amount of turns till the clutch just slips then tighten up 1/2 turn and do a test ride.
The lighter your clutch pull the better.
BSA wrote their manual so if Billy Bunter & his sister were on the bike with a full weeks provisions, the clutch will not slip.
No need to have it that tight and tight = wear on all pivot points.
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Hi guys, a couple of half hitches has always worked for me, cheers
I like a clove hitch for that sort of thing; easy to tie and undo yet holds well. Although when I did my clutch I bunged a cable tie on the lever!
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Thanks a lot for all your quick responses, I'm very appreciative and pleased that I haven't made any glaring errors. Trying to remember the sequence and record it afterwards in the correct order to make sense made my ancient brain work overtime.
duTch, silly billy! I take the plugs out to be able to turn the back wheel easier with the clutch engaged. Ok, I can hear you saying that I should leave the plugs in and get Shirley to turn the wheel for me. When I was a young marine I used to do that with my little finger!
RichardL and kiwipom, I can see you are remarkable gentlemen who know their knots - as is Greybeard - only better! However, if I really must add some praise here for Richard it's that a pile hitch is as good as any for that. I tend to use a clove hitch because it's a knot I've used a lot in the past - make a loop, make another, pass it under the first one, slip it over the handlebar end and pull tight. Easy peasy!
Unfortunately I don't have a dial gauge, maybe something I should look at getting to make it easier - well, hopefully.
Backing off the nuts until clutch slip and then re tightening is a good and well tried method, which I use myself. The 6 turns I mentioned was a note specifically for my clutch to remind me next time - as in a short space of time I'll likely to have forgotten.
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Unfortunately I don't have a dial gauge, maybe something I should look at getting to make it easier - well, hopefully.
I bought a cheapy dial gauge for measuring the crank end float but I haven't found a good way of attaching the dial gauge to the machine to do the clutch. I've found that a piece of bent wire attached somewhere to the bike is good enough to get the clutch pressure plate even.
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I haven't found a good way of attaching the dial gauge to the machine to do the clutch.
Neil,
A couple of folks here, including myself, bolt a steel bar across the inner primary using two of the cover screws. Then, the magnetic indicator base holds to that steel bar.
On another note, if I convinced anyone that I knew the difference between a clove hitch, a constrictor and a pile hitch before looking them all up, I am a success at sarcastic humor. I was impressed by Roger's detailed specificity in naming the knot he used.
Richard L.
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I would just use a cable tie like Greybeard.
A very good write up though, thanks.
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Well, I must admit I did use a cable tie first off. The first one was too thin and snapped when I pulled on it and that was with the lever already pulled in, second one was a lot bigger and overkill. Then 5 minutes later I had to cut it off when I needed to release the clutch lever *conf* . Then I went and got a rope.
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I just use a section of old inner tube around lever and bar on a 4 spring clutch. Used to call them Viney bones!
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As posted on a parallel thread, I used a hose clamp adjusted to about 2" until it jumped ship, then in a 'moment' I had an empty small bean can handy so been using that since- works for me (no pun intended-much), short length of ~2" pipe over ball-ends would do same easy on/off to check whatever
Tried a dial gauge and wire tab thingy, but now just eyeball it (looking down/diametrically across)
duTch, silly billy! I take the plugs out to be able to turn the back wheel easier with the clutch engaged. Ok, I can hear you saying that I should leave the plugs in and get Shirley to turn the wheel for me. When I was a young marine I used to do that with my little finger!
If the plugs are in, you have ready compression to check for 'moment-of-slip'
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If the plugs are in, you have ready compression to check for 'moment-of-slip'
duTch, thanks, but at that stage I was spinning the pressure plate around x 100s to check and adjust for run out - not for compression or clutch slip at that stage.
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hi guys, who is going to have the last word??? cheers
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Me! *smile*
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Surely The Ashley Book Of Knots would call for a "snarling wedge snotter" for such a clutch-ular application *eek*
S
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Snarling Wedge Snotter? - good for the end of a boats spar but a Draw Hitch may be a better choice.
Eh! What were we talking about again?
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Hi All,
Knots of different descriptions, *????* cable ties *????*
A length of stiffish wire wrapped around the grip and lever works for me *smile*
John
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Yeh, What a load of cobblers we're talking, knots, cable ties, hose clamps, bits of old rubber tubes, bits of wire - next time I'm going to use the wife's fingers?
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I'm going to use the wife's fingers?
I'll use the dog's teeth. *smile*
Seriously, I used a quick trigger clamp.
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I used a quick trigger clamp.
I've got a few of those, very handy, would be better made of metal though
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I'll use the dog's teeth. *smile*
Well, it's alright for you - I haven't got a dog *conf* !