I almost asked this question in the current thread about VM-30's, but decided against it because if someone did a search for the topic it would be here.
I already have genuine PWK's for a Kawasaki I bought over 13 years ago for $85 ea. from one of the online parts dealers that is now gone.
I purchased them because of the easier to tune and better gas mileage standpoints
The question I have now is - do they flow as much air as the VM-30's due to their flatslides?
Would the VM's be better on street ported engines? Think EE's stage 1.5 or 2...
here's a nugget to gnaw on. I went from vm34s to tm32s on the lc hybrid and saw basically zero loss. I'd go w the pwks .
Either carb you mentioned will flow numbers beyond the demands of virtually any RD350 or RD400 except maybe those with TZ/TR top ends and/or 10,000 rpm redlines; in real world street riding, max-flow will be seldom if ever reached anyway. Since most riding is done in the mid-rage, smaller venturi carbs will give the most tractable and responsive performance, and may actually lower the power-band threshold - mixing is best at maximum velocity and proximity to the fuel source at the floor of the throat, which occurs at partial throttle settings.
Just my seat-of-the-pants opinion :vroom:
Warren
^exactly. circuit velocity plays I to it a lot for tubability as well. my motor iss pretty ridiculously built and the redlvlimiter is actually set to 10.2k. but I also know you can get 70 hp thru a set of vm 28s. ;)
Just to add to the comments, some years ago Olav Aaen tested flow rates and HP of flatslides compared to round and found 2 things. Size for size flats flow slightly more. In addition he found that HP rose by more than the flow difference.
So I would expect PWK28s to be a better option than VM30s as long as they are jetted correctly.
Mark, how did you find that jetting changed with flats versus round slides?
main jetting went down a tad, i think i was at 350s or so now at 330-340. not much.
That makes sense with a stronger signal across the needle jet. Thx
Thanks all!
You have validated my thinking - and choice of carbs.