Does anyone know the diameter of the ITR Head's Combustion Chamber? 82mm?

 

prolly 81mm, rite? its gotta line up with bore size..

 

yup. 81mm

 

You'd think, but Honda makes .020 overbored pistons.

 

which is why you should quench the comb chamber area to compensate for this. but - its a stock design, so it utilizes stock chamber configuration, not as harmfull as an endyn 86mm.

ive had overbored pistons and its hardly noticeable when looking at the comb chamber 'scarring' that the extra piston area is not being utlized due to lack of chamber size. we are only talking about 1/2mm here..

 

well firstly the combustion chamber is not a perfect circle, more of an oval shape if anything. The diameter from intake to exhaust side is smaller than the diameter from left to right side. Measuring the diameter from intake side to exhaust side it is just over the 79mm range. Measuring from side to side (left to right) the diameter is right about 81mm. hth.

J.

 

Correct me if I am wrong, but the B16 or ITR heads have a round combustion chamber, while GSR heads have the "oval-shaped" quench area, which is actually a better combustion chamber.