PHBG dead spot

The 19 phbg (96 jet, w10 needle 3rd position) on my peugeot 103 (70 kit, simo pipe, 4 petal adaptor) seems to have a spot at about half throttle where it just kills the bike. It sounds just like if you hit the kill switch on the bike with no combustion noise at all, not lean not ritch nothing, but if you give it more gas the bike is fine again.

It happens mainly below about 4000-5000 rpm's and if I don't move the throttle will kill the bike completely. I am assuming that there is just a strange super rich or lean condition happening and was wondering if anyone ever ran into any similar problems.

I have messed with the jetting and needle position/size but the bike doesn't run nearly as well as with the setup I'm using.

Re: PHBG dead spot

I have also been experiencing a weird spot with my 19mm carb. Different jetting and a different needle but I am running a 4 pedal too, it has been a problem for about 2 months now. I thought it was just a lean spot and I have been trying to tune it out by adjusting the needle settings with different jets. I thought I had a lean spot with my PHBG at about half throttle too which sucked cause thats where my throttle position tends to reside most of the time. This makes me have to variate my throttle position alot while riding. My weird spot is just before I get into my pipe so I keep having to switch from going in and out of my power band. Sux

Re: PHBG dead spot

I am thinking that that dead spot is caused by the angle of the cutaway face of the slide. I read somewhere that this effects the mixture at 1/2 to 3/4 opening.

Re: PHBG dead spot

Hmmmm... I had messed with the idle jet hoping that it might help but without success, can you even get slides with different angles

Re: PHBG dead spot

its either the slide cutaway or the needle, I have successfully tuned this condition out of a polini 4 pedal 19 phbg by richening the needle a single notch, depending on where its happening you should be able to tune it out with just the needle, notches or selection.

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