Vitacci pentora 250cc carb issues

[dirtbkr188]

If the Keihin jet I posted above does indeed fit the Nibbi carb, the only drawback is the smallest size for the N424-21 is a #35

[570biker]

Thanks so much for your help. I'll let you know what I find

[570biker]

Well I just heard from Jetsrus. No smaller jets available for the nibbi pe30. It looks like I'm going to have to get a smaller carb. I guess I'll sell this brand new carb.

[570biker]

So question for you guys. The nibbi pe30 is just going to be too big for my vitacci pentora sport 250. No way to jet it down enough. I have a full aftermarket exhaust. I adapted a Honda CRF 230 exhaust off Amazon. It's a 788 pro torq. I also have a 48mm pod filter. Should I go with a nibbi pe26 or nibbi pe28. I've read that a pe26 is what comes stock on a CRF 230. I don't want to purchase another carb that I can't return if it doesn't work. My thinking is the smaller carb might be the better choice because I can always jet it up if need be. I can't jet down the pe28 too much due to lack of jetting choices. The smallest pilot jet available is a 32 but also carburetor flow is another concern. Any ideas?

[Thumper]

So many people have great success putting the Nibbi PE30 on a ZS 250, and with larger pilot jets. Maybe a #30 will work.

The air screw is on the intake side, so opening it will lean it out (a true air screw). Based on others experiences with the carb, I would think that 2 turns out and setting the needle as low as it can go should be too lean even with a #32 pilot jet. It is really puzzling that you haven't been able to find good jetting conditions.

I will be watching this thread to see how your jetting changes go. The kit that I got also bottomed out at #32.

https://www.chinariders.net/showpost...3&postcount=25

Yes, it's a PE28, but I run a #42 and had to lift the needle (shimmed in my case) to enrich it a bit. If it was getting more air (PE30), I would probably need to increase the pilot jet size and/or close the air screw.

[omegadoom76]

Good afternoon Gentlemen, I've been exchanging specs with 570biker. I have been tinkering with the a Nibbi PWK28 carb. finally got it running great but after it been sitting for a while I'm having trouble at wide open throttle on 3rd and 4th gear. mainly 4th. It runs better without the filter (aftermarket). Its got the 125 Pilot Jet, 35 Main Jet, 2 turns out and 1 turn out the Power Jet. Main needle at Position 3 (Middle). Nibbi performance coil, NGK spark plug, GOOFIT AC 6 PIN CDI Box for vertical engine.. which by the way made a helluva difference.. I ordered a manifold I have not installed yet, which will place the carb like OEM did, I'm thinking the distance from carb to engine may be the culprit.