The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: rocket man on 29.06. 2009 21:50
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hi can someone tell me the best way to fit a cotter pin in my kick start
that wont slip after a few kicks ive been throue a lot ove cotter pins
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Bash it in carefully with the biggest lump hammer you have, then tighten the nut - then bash it again.
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that sounds a bit harsh
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Buy a good quality one and insert from the rear. Give it a good whack and tighten nut. It shouldn't move.
Trev.
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thanks Trev
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Damn things I hate them! There are a few different sizes I've come across and it has to be the correct size. My A10s are okay but just cannot get one to fit the M21... I keep looking at the welding equipment... Tell me I shouldn't! *eek*
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First check that the cotter is the correct diameter for the hole.
It should go in far enough for all but the last turn of thread to be proud of the hole without the other end dissapearing into the hole.
There are a lot of really cheap ones around imported by money grubbers that are way below acceptable standards.
Clean the flat on the shaft so that there are no gouges or groves in there.
Note the flat is hardened so it is an oil stone job.
If you do not have any bearing blue rub the flat on the cotter with some dark coloured grease and slip it into the hole, push it down hard with your fingers then tap the threaded end and check to see where the pin is making contact with the shaft ( the marker will be rubbed off ).
Most of the cotter pins I have bought reciently that are the correct diameter have the wrong taper and need some fileing to make them fit properly.
A tedious boreinig job but worth doing properly.
Smacking it with a big hammer will put undue stress on the lever and is the cause of most of them splitting
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For your interest,
If you are using traditional cotter pins and lose the nut ,if you have ever wondered why none of the nuts in you box of bits ever fit,its because they use a 17/64 x 26 tpi cycle thread.
Why? I have no idea. I dont know of any other application for this unusual size thread . At one time I thought it was 7mm x 1.00 pitch (which is just as non-standard)
For years Ive made mine from a bit of stainless rod with an off-set 1/4 BSF thread and fit the way BSA_54A10 says.
Its important not to use the thread to draw the pin in as it will strip .
Mike
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Go on LJ, weld the thing on! Mine was when I got it, but very considerately done so I could grind it off easily and remove to start again 'properly' . . .
Btw, 7 by 1 metric taps and dies are readily available as a standard (though not v common) size Mike N - bought some the other day to make . . . cotter pins for people with heathen metric motorcycles. 17/64ths by 26 also a listed BSC size, but can't have been adopted too often - never had to make one.
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hi ive found out that ive been using bad cotter pins which are too soft
ive found an original crome one which is a lot better *smile*