The BSA A7-A10 Forum
Technical => Clutch, Primary, Gearbox => Topic started by: coater87 on 01.07. 2015 02:00
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I remember a thread where this was the problem, the bike could not be kicked over with the spark plugs installed, but when removed it could be. I got a spare gearbox some years back, and that was the reason that bike was parted out- they could not figure out what was wrong with the motor.
But I thought this was a gearbox problem, but I cannot remember what the problem was.
Anybody know the cause of this?
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not enough Weeties? *whistle*
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Hi coater,
you can sort it out.
Cut off the primarychain and try to turn over the crank with a wrench. If it runs, the problem is at the gearbox.
In this case I reckon the layshaftbushes are wasted.
Klaus
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I don't see a clear correlation between the spark plugs being installed and a gearbox fault manifesting itself.
So I'd go with one of the two preceding responses.
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not to sure of the ground I'm on here but is it possible for a long reach plug to foul a piston in an iron head with high comp pistons, non of which probably count but worth a shout first thing in the morning
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Sometimes the kickstart gears tend to jam and it might just feel like the engine won't turn.....does the kickstart work with the clutch pulled in?
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The box is currently out and has been for some years now, but it is time to open it up. I am still getting the cases ready for vapor blasting, and the gearbox casings are going also.
Maybe it was the layshaft bushing, I just cannot recall.
The idea I believe at the time was the added stress the compression added caused a miss alignment somewhere and made it impossible to kick. Once the compression was off it would go over.
But regardless, the whole thing is coming apart and hopefully the problem will be easy to spot.
Thanks guys!
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mystery pretty much solved:
bushings completely shot, layshaft badly worn. Box put together incorrectly, camplate worn. One extra bolt floating around inside box. *sad2*
Is there anywhere that sells new gears for the a10? I need some.....
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Oh, that's all? *smile*
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coater, bad luck with the worn box but you can buy brand new 5 speed boxes over here which the race boys use. not cheap though.
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I am pretty much the opposite of the race guys. I just like things to run correctly, be it one of my old cars or the washing machine.
Oh and I forgot to mention, the single screw holding the inner cover on was replaced with one of those all important wood screws. I think the PO believed those were direct factory replacements. *conf*
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You could pick up a decent second hand gearbox on ebay probably much cheaper than trying to find someone who can supply new gears I should imagine new gears will be quite expensive. Try typing the following numbers into ebay and you will get an idea of the second hand costs. 36133292355 351440135862 If I was in your position I would be going for a second hand box there are always some on ebay.
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I'd be looking for a complete box as well. How many gears are we looking at? Look up part #'s and I'd check here 1st. http://www.goldstarbsa.com/Plate_3.asp
They were very helpful to me years back.
Cheers
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If there is not a ready supplier on the aftermarket (still need to contact the site you sent me to Musky- they scare me a bit right off with the Goldstar and Scrambles parts but we will see).
I guess its new bushings and shaft grinds and maybe some gear shaves. I will combine the best parts from two boxes and any other parts I have around. It may be a bit crunchy, but maybe with a careful build and better clutch option it will be all right.
In the mean time I will look for a better box or two.
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Fairly sure it was DraganFly I saw some listed a while ago (last year)...don't get your hopes up, but I just had a look and they have some listed, some made to order, some not available but reasonable prices- cheaper than the ones I just bought from Germany for my Gutzzi...the reality may be different
https://www.draganfly.co.uk/index.php/bsa/bsa/a710--b3133--c101112--m202133/category/1097-rigid-plunger-a-group-s-arm-a-b-group-and-all-4-speed-c-group (https://www.draganfly.co.uk/index.php/bsa/bsa/a710--b3133--c101112--m202133/category/1097-rigid-plunger-a-group-s-arm-a-b-group-and-all-4-speed-c-group)
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Just spotted these on eBay ... nothing to do with me...
http://www.ebay.com.au/itm/bsa-4-speed-gearbox-internals-/261950195702?pt=LH_DefaultDomain_15&hash=item3cfd72c7f6
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Thanks for the info and links guys!
I wonder what the "five speed conversion" is the seller is talking about in the ad? Anyone done this, or know any links to information on it?
By the way, the layshaft in the box with the floating bolt is also cracked. Its starts near the key where a shaft will normally crack, but how do you manage that on a motorcycle with barely more horsepower than a riding lawn mower! *eek*
Those internals I no longer trust at all, but the case is the good one. At least I spotted that before I sent it out for grind, I know damn well those guys would have ground it first then told me it was cracked.