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I race a formula 2 sidecar that is running R6 13s engines. Last year I had a crash and the outfit ended up upside down, the engine was running upside down for a short time so I decided to rebuild it. I have purchased new main and big end bearings and rebuilt the engine, however the crank is very still to turn with a ratchet. I have split the casing again and there is definitely binding happening on the main bearings.

I have a copy of the 2008 service manual and followed that when rebuilding. What I am confused about though is the tightening sequence of the crankcase bolts. I also have a kit manual and can see that the sequence is very different, and the final angle stage is missed out.

From the 2008 Service manual I have

Font Material property Parallel Engineering Rectangle

From the 2010 Kit manual

Font Engineering Parallel Auto part Rectangle

So it looks like the final angle is not done? This appears to be the same in the BN6 manual also, no final 70 - 80 degree tightening.

If I tighten the bolts up to the 3rd stage, it still spins freely by hand, only when I tighten the further 70 - 80 degrees does it start to bind.

I am led to believe this engine has a GYTR crankshaft but I am not sure how to confirm, that's why I was looking at the kit manual also.

I have a single number 5 on the crank cases (This means all are 5 right?).
The crank is stamped 1 2 2 2 2. So I ordered 2 brown mains for closet to the flywheel and the rest are Blacks.

Anyone have any ideas?

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