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Power Jet Carbs on Reed Valve Engines
Posted: Wed Jul 04, 2012 6:21 pm
by nellyboyo
A learned friend of mine says that power jet carbs are no use and should not be fitted to a reed type engines. He did start explaining but lost me a bit to be honest.
Is this a valid statement ??
Re: Power Jet Carbs on Reed Valve Engines
Posted: Wed Jul 04, 2012 6:37 pm
by Muppet
lower average air speed or something like that; Meself think they look like your trying too hard, nowt wrong with a 22 jetex
muppet,
Re: Power Jet Carbs on Reed Valve Engines
Posted: Wed Jul 04, 2012 7:36 pm
by Darrell Taylor
its all down to if the power jet design delivers or not some designs have low delivery rates ,the keihin pwk copys have a few diff power jet designs some good some bad so treat all carbs individually
i run a dyno with lambda air fuel monitoring and see most power jets deliver ok richening fueling by a point or so depending how there set up,so one with poor delivery wont allow the main jet to be dropped much and another with strong delivery can drop the main some more
i actually see piston ports fuel lovely into the overrev but reeds tend to lean out at high rpm so would say the reed motor has a greater need for a power jet
the ignition also plays a role in the bigger picture
Re: Power Jet Carbs on Reed Valve Engines
Posted: Wed Jul 04, 2012 8:30 pm
by nellyboyo
Awesome answer...........Its a Stage 6 PWK , which is a quality Keihin copy. The best of the few I`ve owned but the 1 st with a power jet.
I`m running rich from 1/2 throttle up at the moment as I`m only just setting it up so will be looking to jet down .
Re: Power Jet Carbs on Reed Valve Engines
Posted: Wed Jul 04, 2012 8:52 pm
by Darrell Taylor
does your power jet sit flush with the venturi or stick out
on that carb fuel starvation can be a problem so run it on maximum float height just before it floods out the air bleeds ,do this before starting jetting as it will change all your fueling if done later check the bleed holes in the needle valve seat are drilled correctly and its retaining clip doesnt snag as ive seen on some before
? piston port or reed whats ur set up
Re: Power Jet Carbs on Reed Valve Engines
Posted: Wed Jul 04, 2012 9:51 pm
by nellyboyo
I,m starting to jet it for an imola with scootrs pipe.
THe power jet sits flush on the intake.
Thanks for the advice I,ll check for those problems as well.