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Scooters - 50cc => Super 9 => Topic started by: L Bo on June 21, 2011, 03:48:22 PM

Title: Squeezing a little more power, modify airbox and manifold?
Post by: L Bo on June 21, 2011, 03:48:22 PM

Hi all,

I have an '07 Super 9 AC that has been good to me, 15,000km good so far. Early on I played with the transmission; upgraded variator, stronger contra & clutch springs, played with the roller weights. I also put on a tuned pipe and opened the jet a little. It is pretty well dialed in and I can get it to top speed with consistent RPM's all the way through to about ~45MPH depending on the wind. (Speedo indicates 50 or more with needle to the M in MPH on speedo).

The next obvious upgrade would be a 70cc kit, pipe, and carb. But until then I was thinking of modifying the air coming into and leaving the carburator. I have an upgraded manifold that is a couple MM bigger in diameter then stock and noticed the hose from the airbox to the carb seems restrictive as well. I saw somewhere (yahoo groups?) a mod to replace that tube with a radiator hose.

My question is would opening the airflow to and from the carb a few MM provide any additional power? I have read the only restrictions to the AC in the USA is the speedboss, exhaust and air intake and not the CDI. The manifold I have is for/from a Canadian version of the S9.

Is this modification worth it? Obviously I would have to adjust the jetting........... just wonder what kind of (if any) performance increase should I expect.

Title: Re: Squeezing a little more power, modify airbox and manifold?
Post by: thebatman on June 21, 2011, 09:50:41 PM

I wouldn't expect anything much at all just from that but remember, flow is always important in the over all sceme of things