[Yamaha YR1 Piston Sizes]

I have to bore out my cylinders and I'm having trouble figuring out what the STD size is for the cylinders! My current piston tops show 6 82

Its odd because they typical go 6 25 or 6 50 or 6 75 if there Over sized by .25 .50 .75

I want to go .50 OS BUT idk if they're already .82 OS but that makes no sense to me and to get a custom made piston and rings would be way to much for this lil bike so i doubt anyone did that.

Any help mates?

[Yamaha YR 1 Hard time find parts]

THANK YOU! Im glad i joined this forum!

[Yamaha YR 1 Hard time find parts]

Ive been on ebay and other various websites but I'm having trouble finding even things like the correct size battery or the gas tank rubber pads.

Anyone know a good place to find parts for these Yr1's?

[New owner of a 1967 Yamaha YR1]

Hello Ladys and Gents! My name is Mike and I've recently purchased a 1967 Yamaha YR1. This bike was the First sport bike yamaha manufactured for the public! Im honored to own one and now its time i restored it and made it my own!