The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: Weggy on 16.07. 2012 11:59
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My 1959 GF on changing down the clutch lever went slack & engine out of gear.Back home the kickstart not turning the engine over and although gear selection sounded Ok no gear engagement possible.Clutch pushrod loose but correct length on removing the Primary case the clutch basket was loose I re-tightened the sleeve nut and it turned with the kickstart but still unable to get any gear. Has anybody any ideas and will the gearbox have to come out?
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The clutch basket would have to be very loose for the key in the shaft not to turn the clutch, would suggest you remove the clutch and check mainshaft key as a first step.
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Thanks Bill you were spot on but the worrying thing is that key had sheared (why)-- but the mainshaft seems to turn aesily enough. Still unable to engage any gear even the gear blever seems to index correctly.
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That sounds not too good Weggy, if you can now turn the engine over with the kick start that's a plus I think.
I think your next step is to remove the end cover from the gearbox and have a look see if you can see anything a miss, if everything looks fine then remove the inner cover. take photos as you go and ask, ask ,ask whenever you come on anything your not sure about.
As the main shaft key sheared it kind of points to something locking up in the box, as you can now turn the box over with the kickstart perhaps wht caused the problem is lying in te bottom of the box so drain the oil out into a clean container and watch for anything lying about in the box.
The gearbox is fairly simple even though it doesn't look that way if you never been in one before so don't be put off, plenty friends here to help provided you have some pictures to help
Keep us informed of progress
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Hi Bill thanks again will do as you have advised and as I have found to my cost photos are essential also sketches.
Will get back to you with a progress report.
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Nb Weggy, You asked 'does the box need to come out?' , no, the box can be stripped apart without removal from the bike, but it's easier to look at everything if it is out, and not a lot more involved.
Cheers n' good luck, duTch
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Hi Dutch-- well thats a relief as it was the one thing I was dreading. But with the mainshaft woodruff key having sheared I feel that it could be serious I am just hoping that with the gearbox cover off all will be revealed.
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G'day Weggy,
sounds like something has either bent or broke in there. Work your way in checking everything, starting with the cam plate plunger (detent). Have you backed it off and tried to select gears? Gear selector plate and quadrant might be worn.
I can't see how the clutch coming loose would cause the prob with the box.
Don't force anything, if it seems stuck jump back on here and ask.
Cheers
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Hi Muskrat the point about the cam plate plunger makes sense having looked at the schematic drawings so will try that first before stripping off the gearbox cover.
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Sorry for the delay in updating you all but as well as the problem with the A10GF for my sins I am also restoring a Greeves Anglian (no comments please). Gearbox outer cover off and no apparent damage I can move the quadrant but still no gears I also tried loosening the camplate plunger to no effect so I assume that the problem is gear selector/cam plate??
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Looks like you will have to dig deeper. Once the inner cover is off it will be difficult to index the gears but can be done. Look for broken dogs ( had one in my A65 that stopped top gear selection) and wear on quadrant and cam plate.
Cheers.
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Yes - inner cover might reveal more, something caused the mainshaft key to shear, and no gear selection still, possible camplate and/or selector fork problem has had consequences to other rotating parts
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Hey weggy,
Before you go berserk and pull things apart, have you tried rolling the bike/rear wheel(if on C.stand) while doing engagement, as sometimes the dogs inside just aren't quite ready to 'hook up', if you know what I mean, ie maybe the shafts and gears just need to realign naturally?
Just seems odd that you suddenly had this issue due to something else?? just a thought/
cheeers duTch
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Hi All
The last pieced of advice from Dutch has done the trick as I ran the gear sequence whilst rotating the rear wheel and after a few turns bingo it all dropped into place and I can now get all gears!! So i can now rebuild everything and get back on the road. Just one question remains and that is do I need to align the dots on the Quadrant and case before I fit the outer gearcase cover?
Once again thanks to all of you for your invaluable advice.
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Thanks Weggy, glad to help, and I reckon you need to at least check the indexing is correct in the correct procedure, but will let someone who knows more, deal with that as I have a plunger and it's different.
cheers duTch
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WHOA - hold on a minute, you may well have got all gears but something happened to cause the mainshaft key to shear, and what ever caused that might be somehting that is now lying in the bottom of your gearbox, possibly out of harms way but probably NOT and is there to cause untold damage to your box not to mention YOU.
You need to take off the inner cover and make sure all is well in there.
We do not want to get mails from members asking where Weggy went
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As the outer cover is already off it makes sense to remove the inner cover and have a good look around.
When done will send a final post to reort the result.
Thanks again everyone.
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I tend to agree. The key may have sheared because of the nut coming loose BUT!!!
I was lucky with the A65 as the broken dog stayed in the bitch (other gear) and prevented further engagement of that dog (top gear). Had it dropped out *eek*.
Cheers
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Yup ok, I'll go with that -fair call, not that hard to have a look, good to see you're on ya toes, cheers
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Your thought was correct Dutch. Almost every time you try to change gear without the motor going you have to rock the bike back and forth till it goes in.
Cheers
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I think I must just do it automatically,even with my Moto and when I went out the other day/night, it dawned on me(not the sun-the idea).
Still worth having a look inside though hey!
Cheers
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Hi All
Had the inner gearboxcover off and all seems Ok no bitts of metal in the bottom of the box and the gears index in the correct sequence. So it looks as if the Woodruff key sheared in half due to the sleeve nut coming loose possibly over a period of tme. Now in the process of re-assembly. Holiday imminent so will post a final update as & when.
Thanks All
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That's heartening, did you pull all the bits right out or just look in? Having got that far,it's probably worth pulling everything out, being not much more.
Good luck with it ,happy holiday!!
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Hi Guys
This could be the last question (hopefully) I am into the box rebuild and when the dot on the quadrant is aligned with the one on the inner cover should the gears be in neutral (cause mine are not) or is this just so that the quadrant locates correctly with the selector fork when fitting the outer cover??
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That's a yes Weggy.
The box must be in neutral and the dots lined up, then fit the outer cover and secure with just a couple of the nuts, next see if all the gears can be selected, turning the wheel with your hand as you work the gear lever, if all's well fit the rest of the fasteners, sometimes you might have to align the dots slightly off one way or another to get all the gears, my Flash box works with the dots lined up but the rocket needs the selector dot one notch lower.
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Bill--- thanks for the prompt reply have just come back in from the workshop and it all checks out so can now put it all back together.