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G1 Sv Won't stay Running.

Started by EM JAY, September 11, 2007, 12:28:25 PM

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benprobst

Hey Guy, I could very well be wrong, I dont have near the motorbuilding experience you and your crew have.

Having said that, I understand the need for a certain amount of overlap. However, I always imagined that at high RPM your explosions are closer together and have less time to complete their respective "burns" If your ex valves are opening too quickly it would result in the escape of unburnt fuel, resulting in a loss of PE(potential) long before it had the opportunity to turn into KE(kenetic).

Also like you stated, if the in valves are opening too soon they will get a slightly dirtier charge due to the back pressure from a racing exhaust. I realize you need the overlap, for both the reduction of intake pulse, and consistent exhaust velocity. But what I have noticed on the big superbike motor (as compared to the basically stock with adj sprockets motor which liked to rev to about 10200) is it is absolutly violent at about 7500-9000 RPM and above that it tends to wain just a bit asking for a shift before 9500, (fine with me, id much rather not overrev this thing, too much money in it already). That combined with slightly dirtier than usual intake tracks led me to believe we were maybe getting a little more overlap than I would like, but I suppose it could just be the big slugs dont like to spin as fast.
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