engine overhaul

[amahaork]

what chemical help to clean piston ring grooves before installing new rings?

[rodbolt17]

soak them in a vat of carb cleaner.

[amahaork]

are connecting rod bolts re-usable?

[rodbolt17]

I don't reuse them.
they are rather critical and if they fail your done.
typically a rodbolt failure will render the block, crank and that rod as junk.

[amahaork]

cannot find info what Yamaha OEM recommendation for deglazing cylinders grit(s). appreciate your help. thank you

[rodbolt17]

don't know.
I don't do patchem up jobs.

take the block to a machine shop that is familiar with 2 strokes and how to properly chamfer the ports when done.

typically with a two stroke a re-ring job is useless.

[amahaork]

I am not going to just re-ring engine without honing.

[boscoe99]

Yamaha does not specify a particular grit size for honing the cylinders. That I can find anyway. 240 grit seems to be most common.

I would not re-ring without honing the cylinders also.

I suspect that you know they make tools to clean piston ring grooves. Here is but one.

http://www.summitracing.com/parts/wmr-w80576

[amahaork]

I know. Thank you.

[rodbolt17]

without the correct type hone(rigid) and without the proper measuring tools, honing is worthless.
typically on a two stroke piston to wall clearance is about .0015.
typically a max of .003"
the average human hair is about .003".
a hand held hone on a 3/8ths drill in the backyard simply wont cut it.
DO NOT use a ball type hone.
it will excessively chamfer the ports.

[amahaork]

I was wrong that machine shop 240 grid stones to aggressive. Thank you