What would be considered " normal " in a twin cylinder with a single pipe ( as simply by using a single you are by defenition creating low bmep )
the Ex timing will be down at 190 duration.
Crank this up to 202 and the cross charging effect adds more power than it looses due to a reduction in power "stroke ".
Rather than go even higher ( been there done that , moved on ) the next trick is to cut the piston skirts such that there is about 3mm of exposed port at TDC.
This creates havoc with the jetting , but using pumper carbs , they can be tuned way wierd and fix that issue.
In my experements with World Champ open jetski title engines , the "bottom open " port is capable of more power than the other option of going REAL high on the Ex duration.
Ive got a thing thats unique and new.To prove it I'll have the last laugh on you.Cause instead of one head I got two.And you know two heads are better than one.
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