The BSA A7-A10 Forum

Technical => Clutch, Primary, Gearbox => Topic started by: huddie on 17.10. 2012 13:32

Title: Gearbox overhaul
Post by: huddie on 17.10. 2012 13:32
Hi All, As the box is out see my last post, I have decided to look at a couple of issues I have with it.
The font cover is off now so with your advice hopefully I can make a start.

First problem is that the kick start jams occasionally. What is this likely to be. The quadrant, the Ratchet pinion or the Ratchet cog itself??. What should I look for to determine if the bits are worn or servicable as I haven't got new replacements to compare them with?.

Second problem 4th gear is difficult to select (only occasionally), if I put my toes under the lever and attempt to move it up a fraction then I can get fourth easily. I must point out that there is no decernable movement of the lever when I put my toes under it!!
The spring looks ok except that I would of thought that the two spring tangs should be crossed over the pivot but are not. I say this because on my other bike 74 kawa S3 the tangs have definitely got to be crossed. It it's not the spring is it more likely to be the selector plate or the quadrant in the inner cover??
Hope you guys can help.
Regards Huddie
Title: Re: Gearbox overhaul
Post by: duTch on 17.10. 2012 14:03

 Dunno off-hand Huddie, you'll just have to look and play with it, maybe the indent plunger/spring needs attention?     
      I think the Kickstart jamming has some kind of part number? similar to sometimes not being able to select a gear whilst stationary(engine off?), just roll the bike in (or out of) gear, as my perception is that the start quadrant and mainshaft ratchet gear teeth just sometimes don't mesh readily.
 The box isn't difficult, just take your time, and play with it-help ain't far away!
 Cheers duTch

  Nb I have a plunger now and though similar,maybe forget what I did know 'bout the S/a box
Title: Re: Gearbox overhaul
Post by: muskrat on 17.10. 2012 14:25
 G'day huddie, have a look at the ratchet pinion bush but also check the kickstarter spindle and lever spindle bushes. All 3 of my A's do it now and then.
4th gear could be a number of things. Sounds like a selector plate or associated parts problem. Check for excessive play or misalignment in all parts. The spring is right.
Cheers
Title: Re: Gearbox overhaul
Post by: chicago on 19.10. 2012 00:45
hi , my kickstart jams because the first tooth on the kickstart quadrant has snapped off and makes it jam. youll prob know this already but when the kickstart jams just pull the clutch in.
all the best, chicago
Title: Re: Gearbox overhaul
Post by: muskrat on 19.10. 2012 09:46
 That reminds me, chicago, I dremeled the first tooth on one of them (can't remember which one) to help engagement. Must be the cafe as it does it less now.
Cheers
Title: Re: Gearbox overhaul
Post by: huddie on 19.10. 2012 14:52
The teeth on the kickstart quadrant look fine but I want to strip it out of the gearbox cover to have a good look. My Haynes comic says to use the clutch lever as a stop to prevent the kick start spring from unwinding, which I have, but what is the prefered way of removing the tension in order to be able to dismantle the kick start mechanism. It I just release the clutch arm while holding the kick start spring pressure how far is the kick start lever going to move before the tension is removed. Having released the tension, stripped it and put it back how does one retension it?
Hi Muskrat, what exectly did you do to the first tooth!! what profile has it got now?
Regards Huddie
Title: Re: Gearbox overhaul
Post by: bsa-bill on 19.10. 2012 18:04
there's not a tremendous amount of pressure on it Huddie.
Hold the cover in a vice or place it on the ground with your foot on it and just pull the kickstart lever back off the clutch arm and let the clutch arm swing in/down

Re-assemble is as they say the reverse
Title: Re: Gearbox overhaul
Post by: muskrat on 19.10. 2012 20:09
G'day huddie, about 1/4 turn tension on the spring. I just rounded the leading edge and a few thou off the top.
Cheers
Title: Re: Gearbox overhaul
Post by: RichardL on 19.10. 2012 20:50
I had the same problem with a jamming kickstart lever and, to my recollection, it is possible to buy a quadrant with a tooth pitch that does not match the pinion. It came down to pointy teeth on the quadrant versus somewhat flat-topped teeth. Pointy teeth being correct, in my case.

Richard L.
Title: Re: Gearbox overhaul
Post by: RichardL on 19.10. 2012 23:17
Hey, I knew we'd been over this before. Check out this link: http://www.a7a10.net/forum/index.php/topic,3220.0.html

Also, I think there is more if you search the word "pointy".

Richard L.
Title: Re: Gearbox overhaul
Post by: chicago on 19.10. 2012 23:52
That reminds me, chicago, I dremeled the first tooth on one of them (can't remember which one) to help engagement. Must be the cafe as it does it less now.
Cheers
hi muskrat, good idea, might have a go at mine, all the best fella, chicago
Title: Re: Gearbox overhaul
Post by: muskrat on 20.10. 2012 03:22
Just make sure that IS the problem. Not good doing it and then later finding it was the bush or something else. *problem*
Cheers
Title: Re: Gearbox overhaul
Post by: chicago on 20.10. 2012 16:20
Just make sure that IS the problem. Not good doing it and then later finding it was the bush or something else. *problem*
Cheers
will do fella, cheer's, all the best, chicago
Title: Re: Gearbox overhaul
Post by: huddie on 25.10. 2012 14:39
Hi all, Got the outer and inner covers off. looking at the kickstart first. The leading tooth on the quadrant looks like its been filed down, similar to Muskrat's mod. The nut holding the pinion on was loose!! (going to replace the pinion). Didn't need a spanner to undo it, guess thats's not good. I have aquired a kick start shaft thats in better nick than mine but the quadrant is missing so I will need to swap it to the new shaft. Am I right in thinking it is just pressed on? does it come of the shaft from the inner end or the kick start lever end, please?. There seems to be rather a lot of play in the kickstart outer bush. Does it make any difference again which way I press it out/in?. Does the new one need to be reamed after fitting?.
With the gear change, The two teeth on the selector plate look a bit worn to me, but it's probably going to have to go back in as they seem to be as rare as rocking horse manure. Going to change the return spring. Likewise outer gear change bush has quite a lot of play in it, This looks like it has to come out towards the inside of the case, again do they have to be reamed.
Hope you can help.
Regards for now Huddie
Title: Re: Gearbox overhaul
Post by: Topdad on 26.10. 2012 10:22
Good morning Huddie , from memory (over 16mths since I did mine ) the splines are only cut so far done the k/start shaft I simply supported quadrant on the vice jaws applied a little heat and tapped the shaft through the quadrant there was a little indent in the end of the shaft I guess from the lathe centre post which the drift was able to use to save damage . came apart very easily. Both gear change and kickstart bushes will need reaming and come out inwards ,if you can use the oven heat nicely with the joint and they'll almost drop out . I got my reamers from Tracy's tools in Torquay. Hope that helps BOBH. 
Title: Re: Gearbox overhaul
Post by: bassgreg on 17.05. 2014 21:43
Hello people.

This kickstart talk is cheering me up no end. My A10 engine and box were re built some considerable time ago and sat in the frame waiting for me to have time and money again.
After ten years I finally got it running last October, then promptly left for six months work. Just returned to find the kickstart doing the jamming thing. Cheers for all the talk, it has given me plenty of ideas.

I will get into the box tomorrow and add any findings to the list. It is nice to know I am not alone.

Cheers.
Greg.

Title: Re: Gearbox overhaul
Post by: bsa-bill on 17.05. 2014 22:00
you may cure it Greg but probably not totally eliminate it  *smiley4* which lets face it is slightly annoying
Title: Re: Gearbox overhaul
Post by: bassgreg on 17.05. 2014 22:16
It seems quite likely, but knowing that it isn't an unusual problem at least means my gearbox and or kickstart is less likely to be terminally ill. I can live with annoying.
Things are far less worrying when you realise you are not alone.

I need to fit a new kickstart spring anyway so the box is getting opened up regardless, might as well have a look while I am in there.

Cheers.
G
Title: Re: Gearbox overhaul
Post by: bassgreg on 19.05. 2014 13:59
Ok,

Having taken on board the various observations about the kick start quadrant, teeth and suchlike the following things showed up when I dismantled my kickstart.

Firstly, the gearbox was completely re-built by a professional some years ago and has basically sat ever since. (I may yet find further horrors since I am not 100% convinced the 4th gear selection feels right, but the bike is not yet finished so that will come out in the shakedown)

The kickstart spring was shot, that is the first thing, which means the quadrant wasn't returning fully to rest. That is now solved with a new spring.
Secondly the first two teeth on the quadrant had a few small burrs on them. Nothing big, but since anything I would consider damage or poor manufacture is a potential problem I re-shaped these with a needle file.

Having re-assembled the box the engine now kicks over far more smoothly, it doesn't seem to catch or jam in the starter mechanism. Time will tell if this remains the case but for now it looks good.

It seems, as with most thing, that getting stuck in and taking care of those little, seemingly insignificant bits of metallic fluff can make a significant improvement. 
Title: Re: Gearbox overhaul
Post by: Topdad on 19.05. 2014 14:43
Hi , i've seen the kind of thing re the teeth on several boxes and am not sure if years ago it was a "mod" to try to stop the annoying jam whichs happens every so often , certainly some quadrants I've seen look to be done professionally. On the bench at the moment I'm sure I've a lovely ,seems new, one and I'll check am sure its champered on those first 2 to 3 teeth. Either way you still need to use the standard procedure ,clutch in kick gently to free the kickstart off. Another case of "sorry sir but they all do that " Hope you don't find anymore horrors ,best wishes BobH.
Title: Re: Gearbox overhaul
Post by: muskrat on 19.05. 2014 20:27
The first two teeth are wasted to help with engagement. I have relieved mine a tad more for a little result. The best improvement was had by replacing the pinion bush, but it still jams from time to time, just not as bad.
Cheers
Title: Re: Gearbox overhaul
Post by: bassgreg on 19.05. 2014 21:04
If the snag resurfaces I will have a look at that.
Title: Re: Gearbox overhaul
Post by: duTch on 20.05. 2014 11:46

I'm wondering if this issue is more relevant to a particular year range..? I think mine might do it occasionally, but if it does I just live with it by whatever I do- will add that if it arises..>note to self..!
Title: Re: Gearbox overhaul
Post by: bassgreg on 20.05. 2014 18:20
Could be. For the record my engine and box are 1957 plunger (semi unit). Last year of production as far as I know and only available as special order I believe.
Title: Re: Gearbox overhaul
Post by: muskrat on 20.05. 2014 20:56
"They all do that sir" My '51 plunger, '57 SS/RR and friends '50 long stroke all do it. The '57 is better but it's been fettled.
Cheers
Title: Re: Gearbox overhaul
Post by: Topdad on 21.05. 2014 12:53
yep, tried to post yesterday but work WILL interupt ! Ive had a '53 plunger , '54 s/arm ,'59 ssa7 and currently a '59 A10 ,they all jammed but only now and then (strangely more so to non BSA mates trying to start them I remember ) my latest does it least but I automatically  clear the clutch and follow through to the end of the kick starter stroke before trying to start the bike . I've had alook at that quadrant on the bench and the first tooth has been ground down second not so much 3rd poss slighthly the rest are perfect so not wear ,be interesting to see how it performs, regards BobH. 
Title: Re: Gearbox overhaul
Post by: duTch on 21.05. 2014 18:41

 Maybe I've got lucky, as inferred earlier I don't notice if it jams or not- even when I went out yesterday- only have to generally kick it once each time.. *smile*

 I don't normally start on the stand, am wondering if it gives the pinion a chance to spin a bees nut if the wheel moves
Title: Re: Gearbox overhaul
Post by: bsa-bill on 21.05. 2014 20:05
Quote
I don't normally start on the stand, am wondering if it gives the pinion a chance to spin a bees nut if the wheel moves

not unless you start it in gear  *smile*
Title: Re: Gearbox overhaul
Post by: duTch on 22.05. 2014 10:43

 
Quote
Quote

    I don't normally start on the stand, am wondering if it gives the pinion a chance to spin a bees nut if the wheel moves

not unless you start it in gear  *smile*

  Maybe didn't think that through so well at 4-sommething a.m. getting ready for the day... *eek*, but I know what I meant.... *conf*

Title: Re: Gearbox overhaul
Post by: bsa-bill on 22.05. 2014 11:14
Quote
but I know what I meant.... *conf*

yeah I knew what you meant too but couldn't resist, your not alone my mind is harmless at 4 am it just the daylight hours  it's not always in sync