GS450 overbore? real quick question...

[sark]

my online research suggets that my gs450 has the same cylinder stroke as the later gs500 twin. What I'm not sure about is the compatibility of gs 500 pistons and a gs450 head. Can I just bore out my jugs and press in 500 sleeves then drop in the bigger pistons? It can't be that simple, it never is....

[IanFrancisco]

GS450 overbore

I can't say that it can't be done, but the question is; Is it worth the effort and expense? For 50cc worth of performance increase... I wouldn't do it. You'd sacrifice reliability most likely. The distance between the pistons would be narrowed and the area would get hotter. The pre-83 CB650 motors which were just overbored 550s had heat related problems for the same reason. I might try to wedge a GS500 engine in the GS450 frame. I think the 450's twin shocks and drum brake are better than the 500's disc and monoshock - lower maintenance anyway.

[sark]

bump. Any thoughts?

[Big Jay]

Years ago we did a really big 450. I believe it was as big as you could go. It ran good then broke the crank. Crank is just not strong enough for max power.

Jay