Starting the mod process

[BBRMotosports]

Sadly that's how it go's lol

[Asako]

The cobbler's children are always barefoot.

[Ercoupe]

Originally Posted by BBRMotosports

The bore may be the same but i'm not going to buy a piston only to find out the wrist pin diameter or location is different. We could get a high compression piston made through any piston manufacture but all that I have talked to will build only a minium of 4. I only need one lol. So thats why i'm doing it in the head. Plus i'm glad I pulled the head when I seen how bad the valve seats looked from our lovely ethenol fuel.

Just talking to my dealer today, and they told me that one cbr250 they sold has been setup as a race bike and it included upping compression via installation of a CBR1000R piston. He said they also enlarged valves, but wasn't sure how much or how.

I think the 250's con rod has a roller bearing big end, so chances are the pistons may be swappable. With roller bearing big end my memory says the con rod doesn't have a split big end.

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[BBRMotosports]

All these little bikes have a needle bearing big end. The wrist pin end has no bearing. I'll look into the piston though. If it's cheap ill nab one. What year bike did the get the piston for?

[Ercoupe]

Don't know which year they used, but a shop manual on the cbr1000 should give wrist pin specs, and specs for the 250 are:
Pin OD: 16.994 - 17.000, service limit: 16.980
Connecting Rod Small End Id: 17.016 - 17.034
Piston Pin Hole Id: 17.002 - 17.008.

If these numbers match up, might be a go.

Good luck!

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[Ercoupe]

Just checked and the CBR1000R, 2011 model year, wrist pins have the same service limit of 16.980 as the CBR250R wrist pin.

Therefore, this has an excellent chance of workng, I would beleive. Wrist pins would be a size match for sure.

Looks like a piston is 54.00, rings 31.00, and pin 11.00. Or about 100.00 plus shipping from MR Cycles. Not too bad.

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[BBRMotosports]

So it's the 1000R not the 1000RR correct?

[Ercoupe]

My error, 1000RR is correct, not 1000R.

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[xda2o2]

there is similar talk: on this 1000rr piston on another thread "Wiseco High comp piston".

I think its a lighter piston, i wonder by how much?

[BBRMotosports]

Originally Posted by Ercoupe

My error, 1000RR is correct, not 1000R.

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Did you look up the price for the rr piston? Its over $100 just for the piston . I think ill just deck the head for free.