Quote:
Originally Posted by Jim Cook
Good Day everyone!
You were quite correct in your 250-300 statement above.
Re: the "275" gasser.
We made several 274cc Gassers out of 250cc bikes. We would take a cylinder slated for repair, and send it, the head, and a 14th oversize Wiseco piston built for the TRX250R Honda quadracer to the cylinder repair business.
They would bore the cylinder to work with the oversized piston, and then coat the cylinder bore with their version of "nikasil" and hone the cylinder to match the piston for proper clearance.
They would build up and then machine down the head to match the new bore.
The piston kit we used was the Wiseco 526M06950. You can tell by the designation that it has a 69.5mm diameter, instead of the normal GG 250 size of 66.40 (minus a few hundreths) Wiseco kit #849M06640 Roughly 3.1 mm larger in diameter.
One more thing... the exhaust valve "flapper" had to be trimmed a bit to keep it away from the larger piston.
We also did this to several Honda CR250R bikes.
Good Riding!
Jim
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Jim, Did this setup yield the desired results? And what were the desired results? Grunt of a 300 with the hit of a 250? or....? Thanks