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I have been toying with the idea of getting a Kawasaki GPZ 500 (known as EX in the US I believe)
It has 58 hp engine with 290° cams and a 10.8 CR.
The engine has a 50 hp derivative with 262° cams and 9.8 CR.
The dynamic CR on both these engine is 7.3 give or take .05.
The idea was to retard the 290° cam to the 262 inlet opening timing (wich would give a 85° inlet closing and be close to the Prius's) and use the 262° exhaust cam.
Then, aiming for the previous dynamic CR, the head (or jug) need to be skimmed 0.72 (58hp Dynamic CR) or 0.75 mm (50hp DCR) for a 12.8 static CR where the valves cutouts in the pistons don't even need to be touched (inlet has been delayed).
Perfect plan !
Until I realised the potential of improvement on a 500cc bike is never gonna match the actual number of an unmodded 250, let alone an atkinsonned 250.
My 250 is already plenty powerful for my ride (to work) to the point I was thinking of getting a 125.
Ho, crap ...
The Kawi engine also exist in 250 form, maybe I need to start on that one ...
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