The BSA A7-A10 Forum

Technical => Clutch, Primary, Gearbox => Topic started by: Tumbleweed on 28.12. 2015 14:36

Title: clutch chainwheel
Post by: Tumbleweed on 28.12. 2015 14:36
hello again everyone , I  am fitting the clutch to my 59 a10 , on fitting the chainwheel there seems to be a lot of play even after tightening the clutch centre nut very tight ,   is this normal if it is how much play should there be , thanks   tw
Title: Re: clutch chainwheel
Post by: chaterlea25 on 28.12. 2015 16:49
HI TW,
Which clutch ??
Photos please

John
Title: Re: clutch chainwheel
Post by: Tumbleweed on 28.12. 2015 17:51
sorry john  I cant show any pics , its a 6 spring clutch and my bike is 59 a10 sw/arm  the centre is tight enough but the chainwheel is not so tight it feels as if something is missing the bearings are all in place , I am rebuilding it from a basket case following the Haynes manual  ,  thanks   tw
Title: Re: clutch chainwheel
Post by: RichardL on 28.12. 2015 18:58
TW,

Others may have a better explanation for this, but, as I see it, the basket will not be stable until the clutch is assembled. The double-row of ball bearings only hold the radial position of the basket. I think the basket can still teeter (so-to-speak) until the whole clutch is assembled and the pressure of the plates hold it in place.  I may be forgetting something here (I have done that before while thinking I had the right answer), so I am prepared for being corrected.

by the way, I don't know if it is even possible to put the clutch hub in as shown in the Haynes diagram, because they show it backwards, as does the BSA parts book.

Richard L.
Title: Re: clutch chainwheel
Post by: Tumbleweed on 28.12. 2015 20:17
so they do Richard l ,  I thought it was just me reading it wrongly  ,  thanks I will get it assembled and see if the teeter is any better  ,   cheers  tw
Title: Re: clutch chainwheel
Post by: chaterlea25 on 29.12. 2015 00:51
HI TW,
Ok,
A point to look at, is the inner race a good tight fit on the shaft adaptor?
A lot (most ) pattern races are about 15 thou oversize  *eek* so loose on the adaptor
I believe the bearing from draganfly is an improvement ?? see recent posts on this

HTH
John
Title: Re: clutch chainwheel
Post by: Tumbleweed on 29.12. 2015 11:38
point taken   
Title: Re: clutch chainwheel
Post by: Rocket Racer on 30.12. 2015 05:54
I have yet to find the improved draganfly bearing referred to, but in the attached image taken from draganfly's site, the ball bearing sleeve 17 can be moved within the basket to improve the bearing location.

The std ball and cage arrangement is awful but with a bit of patience can be made to work satisfactorily. The poor bearing design in conjunction with the narrow push rod both conspire to make getting  clean plate separation difficult.

The aim is to minimise basket wobble, but this was a budget bearing and that is a reasonable challenge if assembling from odds and sods.

Keep us posted how you get on.

Title: Re: clutch chainwheel
Post by: Tumbleweed on 30.12. 2015 08:31
hi rocket racer,     I have just sent for one of the bearings from dragonfly I think the part was number 18 , hope to have it here in a couple of days ,   I will assemble it all and see if it stops the play a bit        tw
Title: Re: clutch chainwheel
Post by: bikerbob on 30.12. 2015 10:58
I have one of those improved Draganfly bearings fitted in my 1956 A7 just had the primary dismantled to cure oil leak from gearbox and can confirm that the bearing runs OK after one year and without the clutch plates fitted just the center nut tightened there is no lateral play on the clutch chainwheel.
Title: Re: clutch chainwheel
Post by: Tumbleweed on 30.12. 2015 12:22
that's good news to me bikerbob.
Title: Re: clutch chainwheel
Post by: Rocket Racer on 30.12. 2015 20:13
that sounds like a good plan *smile*
keep us posted
Title: Re: clutch chainwheel
Post by: Tumbleweed on 12.01. 2016 20:45
hi, rocket racer.  the diagram you sent of the a10 clutch,  where does  number 17 bush go ?  I am fitting the dragonfly bearing     and I put on the back plate then the chainwheel and bearing    but the bearing doesn't look as if both races are being used , there is quite a lot showing inside the chainwheel as if I have missed a bush out is it  17  or does that fit inside the chainwheel body  ,  the original bearing was the same so its not the  dragonfly bearing  can anyone let me know if it should sit like that . also while I am here what is number 13 on the drawing    thanks  pp
Title: Re: clutch chainwheel
Post by: chaterlea25 on 12.01. 2016 21:10
HI TW,
Number 13 is the scroll that supposedly keeps in the oil, it is pressed onto the taper adaptor
Number 17 is the bearing outer race, it should be a tight fit in the chainwheel, final positioning is somewhat of a compromise ?? where it does not keep the chainwheel friction material away from the rear plate

HTH
John
Title: Re: clutch chainwheel
Post by: Tumbleweed on 13.01. 2016 08:15
thanks john, number 13 was missing from the box marked "clutch bits" in my basket case ,  so it doesnt look to me as if there is anything else missing the bearing outer race is much narrower than the bearing it seems odd to me ,        tw
Title: Re: clutch chainwheel
Post by: olev on 13.01. 2016 08:30
Brian,
Sometime back you fitted a sealed ball bearing into a plunger clutch.
how did it go over the long term?
Is it still working?
cheers
Title: Re: clutch chainwheel
Post by: Tumbleweed on 13.01. 2016 10:11
hi olev , I think you have the wrong geezer,   tw
Title: Re: clutch chainwheel
Post by: Tumbleweed on 13.01. 2016 13:28
hi again , the  bearing is fitted, and there is still loads of play I still have a feeling something is missing I was looking at bikerbobs pics and the last one shows the chainwheel being almost flush on the inside of the wheel with the bearing  , on mine there is a third of the bearing sticking out from the inside of the wheel  just holding the second row of balls in ,    that's why I think something is missing     I managed to get a pic
Title: Re: clutch chainwheel
Post by: chaterlea25 on 13.01. 2016 22:39
Hi TW,
That must mean that the outer race is sticking out through the rear of the chain wheel????
I am assuming that the "new" inner and outer are the same width ?
If so press it back  so as both parts line up

HTH
John
Title: Re: clutch chainwheel
Post by: BSA_54A10 on 14.01. 2016 01:21
There is a very thick plain steel plate that goes on the clutch center first.
Without it the clutch basket will sit too close to the back of the chain case.
Title: Re: clutch chainwheel
Post by: KiwiGF on 14.01. 2016 05:14
From memory the outer race protrudes about 020 through the back of the chain wheel on mine but you adjust to suit the thickness of friction material in the chain wheel you have, so maybe you press it back out a bit to cover the balls ?

Is the all Metal friction backing plate behind the chain wheel (part 15) in good condition ? without recesses worn into the plate where it fits against the clutch centre?

Are the friction pads in the chain wheel the correct thickness? And not worn too thin?

Asking the obvious....sorry....the inner race of the bearing is definitely back hard against the backing plate? did you trial fit the big clutch nut to force it all the way back?

I have a Draganfly style aluminium caged bearing and my clutch works great, but I can't see how the bearing significantly reduces wobble when the clutch is fully assembled  *dunno* I suppose a better bearing might help but if it wears even slightly I would think the chain wheel would be free to wobble....
Title: Re: clutch chainwheel
Post by: Brian on 14.01. 2016 05:25
Olev I have sold that bike but as far as I know it is still working well.
Title: Re: clutch chainwheel
Post by: Tumbleweed on 14.01. 2016 10:55
hi  everybody thanks for your help, the outer ring on the chainwheel is 10mm , the bearing is 15mm, if I move the chainwheel    out to the front of the bearing making it level the chainwheel is out of line with the engine sprocket , I am thinking perhaps it is the wrong chainwheel or something , it has been put together as the drawing ,    tw
Title: Re: clutch chainwheel
Post by: Tumbleweed on 23.01. 2016 08:46
thanks for your input chaps , ive bought a 4 spring set up off fleabay ,  it will arrive in a couple of days   . tw