Shimming the speedo gearbox

I need to shim out the speedo gearbox on my 750 about .020" so it will clear the cover plate. The PO dealt with this by filing out the ID of the cover plate, but that left a big ragged ugly hole. I have another cover plate that hasn't been butchered and would like to use it.

So, what to do for shims? The parts list does not show any. Is there an existing part that will fit (like using iso shims to shim the gearbox layshaft) or do I have to make one somehow?

Debby

On my Trident I just used a suitable washer between the spacer & the g/box.

Shims should be available at bearing shops and automotive supplys. If you take samples or the measurements in you should be able to get them easily enough. Every differential drive uses shims to set back lash and tracking on the crown and pinion gears for example and there are many sizes of them around from small imports to trucks etc.

Or I understand you can get a new top-hat bushing for the gearbox. That may help. You should be able to find a spacer or washer that is the correct inside/outside diameter to put between the top-hat bushing and the spacer inside. Also helps to assemble the rear wheel in correct order according to the workshop manuals. The gearbox should not contact the cover plate.

Dave
69S

Think about this, if the spacer behind the speedo drive has crushed to a new thinner dimension would you really want it on the bike? How long would it be till it simply opened the crack further to change again? And there are speedo drives out there that had a steel pressed in backing bushing so be careful some of the parts are getting harder to find. worth asking the question but you may not find the simple answer to be the right one.

I'll bet that if you replace the "speedo gearbox spacer" Part Number NM13270, your problem will be solved.