Help me tune my bike KymcoForum! :) Carb Tuning!

[Shredder111]

Hey guys,

I've been getting into the mechanical aspect of powered bikes more and more these days. I started off with mountain bikes, but seeing as how I need to get around, I definitely need to understand performance issues. I recently purchased a new exhaust, (Leo Vince ZX-R) along with a main jet kit, Stage 6 air filter, BR8HIX iridium spark plug, and Polini race variator. My main jet is currently a 70, with stock settings and a normal air box. What main jet should I upgrade to, with the listed upgrades, to get me started? I know you are supposed to do spark plug color checks while tuning and all that, but I need a good size to start with, so that I can get to work in the meantime. I am looking for smooth and steady acceleration and a high top end for longer distances. If you have any tips about this topic, I would greatly appreciate your input.

Thanks, RJ

P.S. - The main jet sizes I have to work with, include 82, 85, 87, 90, 92, and 95

[Nori]

Your in the right forum , so tell us first if you have 2t or 4t ?
Kymco super 8 is restricted very bad
First one is the vario :


2nd : cdi box rpm restriction , to de-restrict you should cut or take off the pink wires


Im having a 4t super 8 '07 with polini variator and cdi de-restricted nothing else
and im having 65-70 km/h the acceleration is much better but the rpm are high in top speed
so if you want a better top speed you should install polini with heavy rollers or stock one's
stock polini rollers are 6.9 gr
so the lighter rollers means better acceleration less top speed and noisy or shaking in your leg room
with main jet kit , exhaust upgraded your acceleration would much better.

[Pimpy1]

91 jet with 9gram weights got me the best all round performance.

[Sinner]

I have the same pipe and I am working on mine now.  I have a K&N style air filter and with that a 94 main jet was too lean.  I went up to a 98 and I think that looks to be a little rich.  I have not put in the 96 yet but that is probably about where it should be.  If you are worried about being too lean with the Stage 6 air filter you could just modify the stock air box by drilling some holes in it rather then using the new air filter.