V4 and V6 crank bearings

[YamahaV4]

Hi

What is V-model crankshaft's diameter tolerance? I mean the diameter tolerances for the crankshaft's bearing surfaces.

If a bearing surface is corroded and should be ground and polished is there oversized roller bearings for sale anywhere to allow a smaller shaft diameter?

Thanks, JJ

[boats.net]

Would need to know model numbers for crank specs but no Yamaha doesn't offer under size bearings for the 2 stroke or 4 stroke cranks.

[YamahaV4]

Crank specs

Ok. I actually opened a Yamaha 200 model code thread on the same motor... I have a service manual but it has the runout limits only. I think that I have seen the diameter tolerances in a factory manual. The crank is off a Y200 year code T (=2000). 6R5 rods.

Thanks

>Would need to know model numbers for crank specs but no Yamaha doesn't offer under size bearings for the 2 stroke or 4 stroke cranks.

[boats.net]

I looked in service manual and runout is the only spec listed, it doesn't give std diameter or wear limit.

[cyrillefrenchy]

i don't think there is any wear tolerance on 2 stroke crankshafts as they are hardened on the surface and they work with roller bearings not as a 4 stroke crank where the oil is injected under pressure to eliminate the play between crank and bearings .( to a certain point off course)
i would say : as long as all the journal surfaces are all looking good and measure the same size at more or less 1to2 /1000 you should be good .
now if the crank is corroded, i heared some companies are rebuilding recharging the crankshafts, but i never tried that.
frenchy