Hitchcocks Forum

Having found a crack in my gearbox casing, a new one has been purchased (the main bearing have being put in prior to its delivery. Shafts have been checked and run true, all gears appear in order. new bearings have been fitted in casing and carrier plate all are seated properly. gears have been assembled and reassembled quite a few times now, checked and double checked. Assembly is done as per Official workshop manual, and all is good until I start to pinch the carrier plate up. Everything turns freely, but as soon as the bolts are taken past finger tight on the carrier, everything locks and becomes impossible to turn. Sadly i dont have an engineers block to check the carrier is flat, but there is no obvious damage. The original stripdown was done due to a failed main bearing. Has anyone else encountered this...am I missing something obvious...for the time Ive spent on it, I would have been better buying a newbox..but hey wheres the fun in that

I wonder if there's a slight machining error somewhere in the new casing, maybe where the carrier plate sits. If it's sitting just a few thou too far in all your clearance goes when you bolt up. Maybe try shimming it out a teeny bit? Or see if thinner thrust washers are available.

I have had similar with the kickstart binding when the outer cover is screwed full home, in this case aftermarket gaskets of too skimpy material were to blame.

A.

Thanks Adrian, there's no gaskets in there as yet. I'll measure out the new casing. I took everything apart again so at least it's in a position to do it. I did wonder about washers between the gazing and carrier plate, but wondered what that would throw out on the other side. Thanks again for the reply

Check the 2 dowels are bottoming out, Richard

Thanks for that Richard...will be double checking that now...I knew I could have forgotton something basic

Hi Chris.. Did you solve the problem with the carrier plate?
I've similar problems after having a new kick starter pawl on my Sixty-5.

When the gears start to bind and go tight, try tapping the ends of the shafts with a copper mallet, or a hammer used with a copper or alloy drift - they might just free off.

Thanks Paul... I'll give that a try.

Hi Guys thanks for the tips. Still havent had chance to look at it yet, been really busy with the business. I have alrady had the tempatation to hit with a big hammer but have resisted...will try all the tips when i gt back into the garage

Check this : https://www.hitchcocksmotorcycles.com/p ... pages/2367 - Part number 19 is a thrust washer - its an odd shape and only fits into the casing a certain way, unless its in the right way it will do just what your gearbox is doing.