The BSA A7-A10 Forum

Technical => Clutch, Primary, Gearbox => Topic started by: Brucie64 on 26.05. 2010 15:36

Title: A10 Clutch Operation
Post by: Brucie64 on 26.05. 2010 15:36
As this is the first & only BSA I have ever owned, I have no idea whether my clutch is operating correctly or not.

All the gears operate very well both up and down the box however I have an issue when trying to get my bike into neutral once stopped with the engine running. Once the engine is killed, neutral snicks in just fine.
Is this the norm for these old bikes or is mine out of adjustment somewhere?. Mine has been like it ever since I bought it a couple of years back.
When using the clutch normally, the bike pulls away smoothly and changes gear without as much as a clunk, I have however noticed a little clutch drag when the bike is at a standstill, with the clutch pulled in and in gear.

I have tried to adjust the clutch both at the handlebars and by taking the little panel off the side of the gearbox and adjusting the clutch arm screw as per the manual but to no avail........still no neutral (note the clutch arm is parallel to the side of the gearbox when pulled in which have been told and believe is correct). The bike has also had the clutch out so I could change the gearbox sprocket a month or so ago and all the clutch plates looked fine and still had plenty of wear left on them.

Anyone know what I could try next?

Title: Re: A10 Clutch Operation
Post by: lawnmowerman on 26.05. 2010 18:25
Hi Bruce

I have yet to ride a classic british bike which does not have the same problem. What I do is snick it into neutral just before coming to a standstill - either that or ease the bike forward or backwards while selecting neutral.
Part of the charm of classic biking!

Jim
Title: Re: A10 Clutch Operation
Post by: shabashow on 26.05. 2010 20:40
You'll soon get the knack of coasting up to stop signs and traffic lights, or hope you wont be held up long as you squeeze the clutch lever waiting for the lights to change!
Title: Re: A10 Clutch Operation
Post by: muskrat on 26.05. 2010 20:58
G'day Bruce,
                      I have only ever found few bikes that will select neutral at idle. I think a bit to do with straight cut gears and dogs.
 Drag can be caused by either the pressure plate not lifting squarely or worn notches in the basket or center. The notches (if not too bad) can be dressed out with a file and the springs adjusted to give even lift of the pressure plate.
 Even with a sNorton diaphragm clutch on my cafe it's only at a very low idle that I can get neutral.
Cheers
Title: Re: A10 Clutch Operation
Post by: Big Nick on 26.05. 2010 21:20
i would suggest firstly using ATF fluid then surflex clutch plates then next SRM do a needle roller bearing conversion and there own pressure plate , dragging and slipping problems gone, my swing arm A10 has a tony haywood belt drive and norman hyde thin friction plates. All that bring the bike up to a state where commuting daly is ok .
Title: Re: A10 Clutch Operation
Post by: a101960 on 26.05. 2010 23:21
No doubt about it the SRM needle roller bearing and pressure plate works very well.

John
Title: Re: A10 Clutch Operation
Post by: mike667 on 27.05. 2010 00:32
I have 6 old brit bikes now and with the exception of my commando i have no bike that will easily go into neutral at idle - even with my A10 having the srm pressure set up and  ATF I have to mess with it - i have found that shifting down into  second and gently coming up i can catch neutral at idle 90% of the time, but never directly from first - i think each old classic has its little nuisances ( A10 and the kick mechanism locking up is another of my favorites) -  just keep messing with it and you figure it out ..

drag, like muskrat said, can be caused by grooved cluthch hubs and plates- the groves can appear very minor - fortunately besides filing the grooves out the clutch  hubs they are pretty cheap (70-80 USD - i just replace mine a few months ago)
Title: Re: A10 Clutch Operation
Post by: trevinoz on 27.05. 2010 00:57
You all have to spend a bit of time on your clutches.
My '55 Flash with a 6 spring clutch will select first gear while stopped any time without any clashing.
Also I can select neutral while stopped with no problems.
The secret has been explained many times on this forum.
Firstly, make sure your pressure plate lifts squarely and evenly.
Second, measure the fulcrum length on your clutch lever. The most common seems to be 7/8".
I initially fitted this type to my bike but had the same problems as most even though I had fitted a home made radial bearing lifter and had the pressure plate lifting as near to perfectly as possible.
I changed the lever to one with 1 1/16" fulcrum and fixed the problem.
My mate who has several A10s has every one of them with clutches that work as well as mine.
  Trev.
Title: Re: A10 Clutch Operation
Post by: wilko on 27.05. 2010 01:56
Yes the old 1 1/16th trick helps!
Title: Re: A10 Clutch Operation
Post by: Russ on 27.05. 2010 02:11
In the mid 70's I spent some time on a 750 Honda,(and enjoyed it) and you always selected netural before comming to a stop. So the Japaness had the same issue. It's not just an English thing.
Russ.
Title: Re: A10 Clutch Operation
Post by: muskrat on 27.05. 2010 05:04
So Trevor, your saying the std 7/8 lever doesn't lift the plate far enough. That makes good sence.
Cheers
Title: Re: A10 Clutch Operation
Post by: LJ. on 27.05. 2010 08:59
I believe that it is important to keep all the parts in their own correct place where they have got nicely worn in, preferably in their own individual places from new. If worn plate tabs go back into different drum slots, even after dressing, then slight binding might occur. It's when constant swapping around is when problems can start. Just a thought I guess...
Title: Re: A10 Clutch Operation
Post by: mike667 on 27.05. 2010 11:47
You all have to spend a bit of time on your clutches.
My '55 Flash with a 6 spring clutch will select first gear while stopped any time without any clashing.
Also I can select neutral while stopped with no problems.
The secret has been explained many times on this forum.
Firstly, make sure your pressure plate lifts squarely and evenly.
Second, measure the fulcrum length on your clutch lever. The most common seems to be 7/8".
I initially fitted this type to my bike but had the same problems as most even though I had fitted a home made radial bearing lifter and had the pressure plate lifting as near to perfectly as possible.
I changed the lever to one with 1 1/16" fulcrum and fixed the problem.
My mate who has several A10s has every one of them with clutches that work as well as mine.
  Trev.

Trev  - so i'm unclear on the difference between two clutch levels (never though about it till joining this forum-shame on me) - please inform whats the difference so i can eye ball mine and see what i have (and where are the 1 1/16 to be found?)

thanks!
 mike
Title: Re: A10 Clutch Operation
Post by: trevinoz on 28.05. 2010 00:38
Mike,
         Measure the distance from the centre of the bolt to the centre of the cable nipple on your clutch lever. [On the handle bar]
This is the fulcrum to which I am referring.
As to finding one, I fitted a pair, check with your friendly retailer.
I managed to get a set from a classic parts specialist in Sydney years ago for the Flash. Sadly, he has died so for the next set I will have to shop around.
Trev.
Title: Re: A10 Clutch Operation
Post by: BSA_54A10 on 28.05. 2010 06:09
A very large part of mysterious, impossible to adjust clutchs is the orientation of the pressure plate to the grain direction of the plate that it was pressed out of.
So some will bend very easily while others don't.
Best solution is to fit the aftermarket , cast alloy pressure plate, prefferably one with a lift bearing and mushroom lifter so that the pressure plate always lifts square.
The most minute skew in the lift can ( and oft dose) cause the clutch to drag just enough to cause your problem.
Either get into the habit of selecting neutral while rolling or spend a lot of time to adjust the pressure plate exactly.
I have know several rider to use a dial gauge to measure "square" and funny enough they have very good clutches that dont drag & cause the box to graunch & crash.
Title: Re: A10 Clutch Operation
Post by: cus on 28.05. 2010 06:53
G'day All,
On the clutch lever thing,
I think there would be some variance with the style of lever also,
increasing the fulcrum, bolt to cable nipple, more pull on the cable,
also I swaped from ball end levers to plain & had alot more gap
from the end of the lever blade to the grip than the ball end one,
creating more pull also. I can select neutral idling or rolling, but
don't have great changes 2-3rd, but I think it's a gear box prob.

regards, Cus
Title: Re: A10 Clutch Operation
Post by: mike667 on 28.05. 2010 13:21
Mike,
         Measure the distance from the centre of the bolt to the centre of the cable nipple on your clutch lever. [On the handle bar]
This is the fulcrum to which I am referring.
As to finding one, I fitted a pair, check with your friendly retailer.
I managed to get a set from a classic parts specialist in Sydney years ago for the Flash. Sadly, he has died so for the next set I will have to shop around.
Trev.

thx trev-  thats what i figured after looking at the levels last night - looks like mine are 1 1/16 but that was eyeball measurement