Porting questions

GoldenMotor.com

theguy2024

Member
Sep 25, 2022
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I'm about to buy another 100cc 2-stroke engine and I'd love some input on proper porting. After doing tons of research I think I'm going to: Widen exhaust and intake port 1mm, raise exhaust 1mm and lower intake 1mm. Trim piston skirt to clear intake port at TDC. Will this configuration mess up things or improve it? also I'm going to be running a clone MZ65 pipe, 36T sprocket, hi compression head, reed valve with NT and PZ adapter, PZ19 carburetor. I guess another question is are an of these things necessary? I'm trying to make a bike that'll go 45mph/70kmh+
 

Greg58

Well-Known Member
May 1, 2011
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Newnan,Georgia
Before you do any port timing changes you should use a degree wheel to see what you have, any raising or lowering if not needed will hurt performance.
 
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Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
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Don't mess with the port heights... That'll change the port timing. Some people have good results from it, but most have bad results.

Widening the port, will help; but matching the ports to the intake / exhaust manifolds will work best.

If you add a reed valve, do a windowed piston... (no need to trim the skirt). & with the reed valve you will also need to increase the jet size.