Questions for fine tuning PHBG

I need to talk to someone who really knows what they are doing when tuning Dellorto PHBG carbs.

I am running 21 phbg, 96 jet (running a little rich). The needle is a W9 with the clip on second from top notch.

This setup was perfect up until I changed the pipe and removed the head gasket.

I have 2 problems.

1. If I accelerate just a hair past 1/8th throttle, it bogs and I have no take off. If I move the throttle back down a little bit it picks right back up and I have to wait for it to accelerate to 10 mph before I can give it anymore juice. I believe the fix for that would be dropping down the needle a notch to restrict fuel flow a bit more. But, here is my other problem:

2. When I am past 1/4th throttle, I am having problems with the fuel cutting off too quickly when I let off the throttle. This would be fixed by changing to a needle with a different taper, something higher than a W9.

So if I changed out needles, would I still move it down a notch? Do I need to switch out needles? I would like to get someones skilled opinion. I want to make sure I am understanding everything correctly.

Re: Questions for fine tuning PHBG

Overpriced Parts /

What bike? What timing? What kit? What pipe?

Re: Questions for fine tuning PHBG

Did you need to post this here and in Performance?

Maybe you should just get some rollerskates. (edited)

Re: Questions for fine tuning PHBG

Pug 103, 70cc polini w-port, gianelli pipe, high comp head w/decomp (plugged), malossi 4 petal reedblock and intake, timing is 1.1 btdc, b10hs plug, max temp around 350-370.

Re: Questions for fine tuning PHBG

Overpriced Parts /

I posted on your other post

Re: Questions for fine tuning PHBG

Why did you remove the head gasket? Have you checked for head leaks since doing so?

Re: Questions for fine tuning PHBG

I removed it to boost my compression, decked the head, no leaks. I am not a moped newb, the bike does 60mph and is without problems, I just feel I can tune the carb in a little bit more that it is currently

Re: Questions for fine tuning PHBG

You have to think you are tuning 3 circuits. The early bog is probably the pilot jet. You may have to go down. The transition or middle of the throttle is working off a combination of pilot and main. With the taper of the needle making the difference in the middle of the throttle range. I would consult the phbg tuning guide on the wikki. It shows what throttle positions works off of what jet. Good luck

Re: Questions for fine tuning PHBG

Re: Questions for fine tuning PHBG

That is good man, thank you

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