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Scooters - 50cc => Super 8 => Topic started by: Magoconnor on May 18, 2018, 02:02:08 PM

Title: Calling All Experienced Tuners!
Post by: Magoconnor on May 18, 2018, 02:02:08 PM
Hello.
I am writing to you about some problems I have with my scooter.
Kymco super 8 4 stroke 72cc.

I hope you guys can help me out.
My scooter do not really reach high rpms when I give it full throttle, as you can hear in this sound clip https://www.youtube.com/watch?v=J9nICDpuOrg (https://www.youtube.com/watch?v=J9nICDpuOrg)

Which in turn limits my top speed..

I have removed the following restrictions:
Cut one of the small wires at the cdi box.
New sliding tube and new polini variator 4.5 gr.

In addition to a 72cc bbk I've also fitted a larger cylinder head with bigger valves. I have had to increase my main jet size, following the installation of the new bigger cylinder head. Right now I'm running with a 110 which I think is pretty high. I have also tried higher and lower main jets with no increase in performance. The rpm does not go up nor does the top speed.

I have thoroughly checked for leaks but found none.
The scooter starts immediately and keeps idle fine.

Timing is correct and valves are adjusted.

My setup:
72cc gy6
47mm cylinder head 21 in / 19 out
Performance camshaft
Polini variator 4,5 gr
Unifilter
Leovince exhaust
15% stronger torque spring
Stock carburator
Title: Re: Calling All Experienced Tuners!
Post by: AylmerFreerider on July 18, 2019, 08:38:33 PM
I have a similar set up and I only put a 92 jet in the carb.

I also have 6.5gr weights and I am hitting 7800 rpms.  These are meant to hit a power band at 7400-7600 rpm.

I would look into gettin and installing a tachometer just to make sure.