The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: Topdad on 04.09. 2012 11:31
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Hi just stripped down the clutch and true to previous form came apart without any drama's but with the clutch centre and rollers still insitu i placed it on top of the vice and spread a dust sheet under vice and work bench ,(just incase) and tapped the centre out very gently it dropped with precision right in the center of the vice but just as it dropped I thought I saw the glimmer of a roller shooting off as only those little bleeders can so question is can anyone, off the top of there head tell me how many rollers should be in the run? Brain has gone blank ,it looks ok but..... thanks in anticipation BobH.
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20, and make sure they are 6mm wide not 1/4". diameter is 1/4". May have a couple of spares if needed. Dave.
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many thanks , I was right i've only got 19 ,in the immortal words of Muskrat ...BUGGER , Thanks Dave for the offer i'll check my spares and will let you regards BobH
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I have a variety of old speaker magnets for that, and a little one on a bit of wire for inside things,and put it in a plastic bag to not collect all the filings and swarfs
Good luck
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I have a variety of old speaker magnets for tha
Nice one Dutch and to think of the number of old speakers I've bin'd
Aldi ( and Lidl I bet) sell sets containing 2 magnetic tool rails and 2 magnetic trays round and oblong for not too much money, founf the tool rails great but up till now haven't found much use for the trays, however next time I'm in the clutch ...............
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Had a good luck around the vice and floor and found the little beggar lodged under the edge of the bench ,how it got there god alone knows but all safe and secure in a box until I put it together again thanks for all the help ,next time in Aldi I'll get one of there magnetic thingy's really could be very helpful, BobH.
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Just had another thought, if you can find an old speaker magnet,or similar, put it under the item before you pull it apart, and if anything falls(or is magnetically sucked !) you'll know where to maybe find it, but due to a guy called 'Murphy '..........
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Check out the width of ALL your rollers, on two A10 4 spring clutches I have worked on in the last month both wrong 1/4" rollers, 2 on one bike and 1 on the other? How? I expect the PO dropped one and bought what they thought was right. So check them all. Dave
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will do ,many thanks Bobh
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Ok just by chance, I ran out of bits to stick in the engine, so dug out the clutch to chuck it on, and whilst washing the rollers, took a count- 18..-? ok hmm but it's ok I checked and mines a plunger and I didn't lose any (magnet on hand)......however,
I got thinking about the size(6mm), as when I bought these I specifically remember being told " 1/4 x 1/4 "...and they are- 0.149.
I don't really intend to get technical,but need to know the correct size as have an order ready to pay for at Draganfly, who list them (part# 26-650)as 1/4 x 15/64, (approx 0.234"/5.95mm), but service sheet #208 just casually mentions "1/4 x 1/4 ".
There's only .05mm/.0015 between 15/64 and 6mm, thirteen and a half thou (0.0135)/0.35mm between 6mm and 1/4".
My clutch centre has 0.260~ between the two 'roller-end faces'(thrust washer/clutch centre), 10 thou-ish clearance/tolerance/end float for 1/4 rollers, which should be ok, and my maths tell me that shorter rollers (15/64 or 6mm) will float more..?
Q:- Is there a vital bit of information that I'm missing out on??
Hope that wasn't too busy, I got Lauren to chuck in 20 x 6mm rollers anyway, so if I don't use them, someone may.
Cheers ,duTch
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Not sure about the plunger, I was referring to the swinging are 1960 A10 with the 4 spring clutch.
"There's only .05mm/.0015 between 15/64 and 6mm, thirteen and a half thou (0.0135)/0.35mm between 6mm and 1/4"."
I agree that it must be 15/64 not 6 mm it would seem strange to mix imperial and metric. but close enough if you are checking the size.
. Dave.
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Thanks Dave,
I composed that in a rush, to have info before I paid for bits, but as I said I got the '6mm' anyway, and a few spare 1/4 x1/4. All mine measured 0.249" (not 0.149-typo/braino), except one is a couple thou smaller, dunno how much difference it'd make but hopefully new ones are same as other 17.
What I'm curious about, is that I googled the part# 26-650, and had results of a lot of different sizes, (obviously not correct), and even DragAnfly sends me to '6mm'.
I've attached a pic of the ~0.260 measurement, which should be enough to cope with 1/4" wide?
I have 2 baskets, and the corresponding thickness of the chainwheels gives about 3-5 thou lateral play on one, and 10 thou on the other, as the thrust washer thickness there wouldn't make a difference, can this be otherwise shimmed to decrease play ? (probably get chewed up)
No big deal, it worked ok before, but figured best double check, and would prefer to have the 'full' width roller(1/4), if that's as specified, and could make a small difference the other way to (1/4 in 4spring), especially if there's a bit of wear in the bearing surfaces ?
Sorry to 'hijack' your query Bob,
Cheers for now, duTch
Never thought I'd get so involved in something I was just going to strip apart, clean up ,and throw back together!!!
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"and could make a small difference the other way to (1/4 in 4spring), especially if there's a bit of wear in the bearing surfaces ?"
IF you use the 1/4" roller on the 4 spring swinging arm clutch, you will find that the back of the clutch centre will jam on the bearings. The Centre should be pinched up to the register on the splined clutch shaft.
The back of the clutch centre should have clearance from the sides of the bearing but its not the bearing width that controls the float of the outer clutch basket so putting in wider rollers will not eliminate play.
It seems to be the bearing ring in the clutch basket that governs the free play and of course any resultant wear where this touches the clutch centre. The main problem I have found is the clutch centre retaining nut sometimes does not clamp the clutch centre and tightens onto the ends of the splined shaft instead. This allows the clutch centre to wobble.
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I understand about the rollers jamming if too long, in either unit, but in an exaggerated example, if the rollers are significantly short, I just wondered if it would allow the rollers to kind of 'twist'(if the 'bearing surfaces'/or rollers, are worn), and allow additional runout.
It's not important, just an observation and we're talking about two different clutches, even though they're similar, and I've had no experience with the 4 spring, but just had a look at the drawings again to see what you mean about the nut, but can't help with that one.
Just had another-other look, now not sure if you're talking about the 4 Spring, or Plunger, in which case I'd suggest maybe you need a thicker thrust plate, if 4sp, dunno, I'd be guessing sorrry.(can't see the taper would affect it ?)
Cheers
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" 4 spring swinging arm clutch" its the only one Ive played with.