Author Topic: Dolmar 7900 Porting Info  (Read 8619 times)

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Offline srcarr52

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Re: Dolmar 7900 Porting Info
« Reply #170 on: September 23, 2014, 11:40:54 pm »
7900 seems to be temperamental in regards to keeping port velocities up, especially intake and transfers.  Big carb and opened up intake killed the power on the last 7900  I experimented with.   Added some epoxy and much smaller carb and it came alive again.   

I don't think it's a port velocity thing, I think it's either the small time area of the ex port because of the piston width or the transfer port charge is to explosive and causes too much mixing so you need to give it as much time to let as much exhaust out as possible. 

 

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