I pulled the cylinder off my Puch Sport Mark II to attend to the leaking base gasket. Should I perform an exhaust porting while I have it off? I was thinking of just rounding the port to match the exhaust outlet. Is this correct? It's a stock cylinder with a 12mm Bing, 58 jet, stock airbox, stock exhaust derestricted.
Thanks.
Do you want to?
Before you get all crazy and start cutting stuff, work more with the things that bolt on. Why don't you get a bigger carb, work in some new gears, get a perf exhaust, better air filter, perf clutch (and tune). By now you have 80%+ of the gains you can get from modding. The porting adds umph, but I think just the addition of a better pipe was much more significant in the way of more power on my project. Portmatching the intake/cyl and exhaust/cyl, added a lot too, even before I ported. A better flo air filter and an upjet probably added the most juice to my bike of all my mods, my biturbo a close second.
I agree with the fubarman - with the Puchs I have had, exhaust mods have brought 10% higher speed (its not like I dyno'd one) porting, well, is a tricky item on the 2 stokes.. just as too open exhuast or intake can cause spoiled air in the combustion chamber.. so can an un balanced port job
However, Mild porting so it looks faster is an excellent mod for bench racing...
Best of luck
You guys are fucking backwards.
Porting is great, but you REALLY need to read up, and understand exactly what you're doing and why. No, you should not just round off the port window to match the exhaust outlet.
For some beginning porting mods, widen your exhaust port by 1mm on each side. Raise it a mm or so if you're not satisfied with the gains you got from widening. Then lower your intake port. Matching your intake and exhaust outlets the the exhaust header and intake manifold help a LOT.
OK. I just smoothed up the exhaust port a bit and did a quick minor gasket match. Drilled the baffle and cleaned the pipe. I'll put it back together tomorrow after work. The exhaust header pipe has two derestricted holes in it. Is there any benefit to drilling any more holes?
Want to post in this forum? We'd love to have you join the discussion, but first: