R90s rebuild impressions

[RickR90s]

Just finished the rebuild on my 130k '74 R90s. 1st over bore and new Motoren Israel forged pistons with new rings, wrist pins installed. (my, is it just me or are those forged pistons too pretty to hide inside a motor?)

I checked the balance on everything from the rods out, but total assemblies were only .5 gram off so just a tiny bit of machining was needed.

Only about 50 miles on it but noticeable improvement in smoothness between 3 and 4k rpm.

Main goal of this rebuild is to eliminate excessive oil usage/coking, caused by out of spec piston/cylinder clearance (even with over-sized rings installed about 5k ago). Bike was pinging very badly and excessive oil coking on the heads revealed why.

Heads were done by Leo Goff in '06 so only a light lapping was needed. (new guides, valves and springs installed)

So far, me like .

RPG

[Chuey]

Cool. Did you go with lighter wrist pins?

Chuey

[Garnet]

These pistons http://www.motoren-israel.com/product_i ... -St--.html that Rick used are much lighter than the stock pistons.

[Chuey]

Oh my, that's almost a pound! That's got to make a really easy to feel difference.

Chuey

[mattcfish]

Way to go Rick!