Hi there,

Can anyone tell me if all 1975 dt 400’s have a crank shim or was it a case by case basis. Mine does not however that does not say that there may have been one originally and a previous owner not re installed it.
The parts list does not show a shim however the workshop manual mentions the shim.
Any assistance would be much appreciated. Thanks

I rebuilt my 76 DT400 about three years ago and I recall it had a shim. I'm sorry to say that I can't recall which side. I put it back like I found it. I just looked up my old Yamaha parts manual for the 75 DT400B and it doesn't show one for the crank assembly. I thought maybe it would reference it as U. A. R. (Use as required) like they do for certain other parts. Can't help you after all.

Shim is on the primary gear side on the ones I've seen. Often, crank will rub the case if you forget it.

DEET might have the shims. He's posted a few times on the topic. Requires some precision measuring of crank width and distance between bearings to determine shim size.

This is the key.

Formula?
Distance between bearings MINUS crank width =clearance.
Clearance DIVIDED by 2= shim thickness.

Put the shim on the primary gear side of the crank.

Thanks for the advice all, I will take the measurements and head to my local engineering shop to source the shim as there is no shim showing in the Yamaha database in Australia.

It is possible it doesn't require a shim. Hard to tell. I know Yamaha got away from the shims on the later 125's and 175's. (1978 model year in the US)