G1 Crankcase Bolts

[kwest0425]

I'm in the process of doing a top and bottom end rebuild of my '81 G1. Top end is easy, but murphy's been helping me with the bottom end.

The biggest problem was with the crankcase bolts. There are seven 6mm phillips pan head bolts holding the crankcase together. Even after using an impact screwdriver, I could only get 4 of them out, and they were pretty well buggered up when I was done. To get the case separated, I had to drill the heads off the other 3.

Once I got the case apart I could get visegrips on the shafts of the bolts. Two came out, the other...snap! I tried heat and ez-out, no help. I ended up drilling the whole thing out and retapping.

Anyway, I'm in the process of getting it back together. My plan is to replace the phillips pan heads with hex heads.

I have two questions...

First, does anyone see a problem with using the hex heads? I have plenty of clearence for the 10mm socket and it will be easy to torque and easier to get out. I can't figure out why Yamaha didn't use them originally.

My second question..

There are no spring washers and the torque spec for these bolts is only 5 FtLbs and I don't see any mention of thread-lock in the service manual. Shouldn't these be thread-locked? And if so, red or blue? There was a white material on the original bolts and God knows they were hard to get out so I'm thinking they had some sort of thread-lock on them.

Thanks in advance,

-ken

[caddylac camper]

If you use the red thread locker and it sets properly you will have to use heat to remove the bolts at a later date so stick with blue if you feel that you need to use it. Use a grade 5 bolt and torque it to the spec. If the white material you seen on the bolts was powdery it was probably just good old corrosion, the kind you get when you have steel and aluminum materials together. Its nasty and makes stuff really hard to get apart as you have experienced.