Best Carb for 125 with big bore kit???

denverscoot50 · Post by **denverscoot50** » Mon Sep 28, 2009 11:06 pm

Hi - OK so I have replaced the bore - did the Dr. Pully variator w/ the 11gm weights - 1500 rpm contra and clutch springs and Prima pipe and the scoot is feeling nice : )... I has become much faster off the line but, (everyone has a big but!) I feel like I have lost some top end. So my wise friends is it the carb at this point?? i have a 95 and a 100 jet for the stock carb - should I try this or just get a new one or something entirely different??? Sorry - and thank you so much if you reply - I am kind of on a steep learning curve at this point and afraid of falling off!

Kaos · Post by **Kaos** » Tue Sep 29, 2009 12:47 am

You're not ready for a carb yet. If you went with the 1500RPM contra, 11g sliders might actually be too light. I'm running 11g sliders right now and just swapped my 1000RPM contra for a 1500RPM, and they're too light in my bike.

If you've only gotten to #100 jets you can open up your airbox or replace with a uni-filter and jet up farther.

I'm still running the stock carb with a lot of jetting/tuning and its doing good so far. Though since I'm likely going to swap my A8 cam for an A9 here shortly, I'll likely get a bigger carb as well so stay tuned for a voodoo-buddy.com review

rajron · Post by **rajron** » Tue Sep 29, 2009 1:46 am

I have heard several people say they had lost top end after the bore kit, but, it pulls much stronger from stop, and will sustain higher speeds up hills. I’m running a big main jet, not sure the size, maybe around 0.118mm, I drilled my own and forgot what I ended up with and I am at altitude, running with an unrestricted air box, pipe, sliders etc; still my top end seems the same, or maybe a little lower, whatever the case its about the same. Those running the larger valves, 150 head, maybe getting higher speeds only because they rev higher – I think we are limited by the final gear ratios, not letting us get the higher speeds some want.

Kaos · Post by **Kaos** » Tue Sep 29, 2009 1:55 am

rajron wrote:I have heard several people say they had lost top end after the bore kit, but, it pulls much stronger from stop, and will sustain higher speeds up hills. I’m running a big main jet, not sure the size, maybe around 0.118mm, I drilled my own and forgot what I ended up with and I am at altitude, running with an unrestricted air box, pipe, sliders etc; still my top end seems the same, or maybe a little lower, whatever the case its about the same. Those running the larger valves, 150 head, maybe getting higher speeds only because they rev higher – I think we are limited by the final gear ratios, not letting us get the higher speeds some want.

My top end was the same until I swapped contras. It will likely be the same again when I get the variator weights right again.

Lostmycage · Post by **Lostmycage** » Tue Sep 29, 2009 1:28 pm

At your altitude, a 95 or 100 main jet with the stock air intake setup might be about as far as you want to go. As others have said, the loss in top speed is from the contra/weight combo.

If you're looking for a good top speed, use the stock or 1000 contra and get some 12g weights. Mix the weights until you get the desired acceleration/speed combo that's most acceptable. When mixing, alternate the weights around (11, 12, 11, 12, 11, 12 when installing in order around the circle). That combo will give you the equivalent of 11.5g. Try that, try an all 11g and an all 12g. This wil give you a better understanding of how the weights effect the ride.