Engine Mounting Solutions

[Floydvoid]

Hello,
I have a 1981 drum brake xs400 and have rebuilt my engine for the last few months.
In the course of the rebuild, I found that the case had a hole and cracked- looks like the chain blew off at one point and knocked off one of the mounting points of the clutch cable cover.

I used an ebay 1980 engine case to rebuild the engine and have everything patched up, I finally put the engine in the frame today, went to push the rear mounting bolt through and ... The holes are too small!

With some research on here and the Yamaha diagrams, the 1980 to 1981 mounting changes to a larger bolt.

All other mounting seems to match up

What is the best solution?

Drilling it out larger seems sketchy. I was thinking of getting a high strength bolt from the hardware store of the correct diameter and length and and tighten it down.

Thoughts?

 

[spectra]

Hello,
I have a 1981 drum brake xs400 and have rebuilt my engine for the last few months.
In the course of the rebuild, I found that the case had a hole and cracked- looks like the chain blew off at one point and knocked off one of the mounting points of the clutch cable cover.

I used an ebay 1980 engine case to rebuild the engine and have everything patched up, I finally put the engine in the frame today, went to push the rear mounting bolt through and ... The holes are too small!

With some research on here and the Yamaha diagrams, the 1980 to 1981 mounting changes to a larger bolt.

All other mounting seems to match up

What is the best solution?

Drilling it out larger seems sketchy. I was thinking of getting a high strength bolt from the hardware store of the correct diameter and length and and tighten it down.

Thoughts?

I had the same issue with mine and ended up drilling the hole bigger. But at the same time also added an additional mount as the 80 to 81 didn't have the top mount like the 78 did right behind the starter. I swapped a 78 motor into a 81 frame.

I think you should be able to use a smaller bolt though.