jerky when slowing down.

ok guys, here's the situation.

Puch Maxi

70cc kit

biturbo exhuast

Amal Carb

I'm still breaking the kit in and have been pretty careful about not revving it too high (one or two times i went a little high, but this problem already existed before i did that). When i let off the throttle and the moped slows, it gets jerky. It doesnt slow in a smooth continuous way, it makes a Brum-Brum-Bruum-brum noise as it sort of jerks to a stop while i'm breaking. It's not so jerky that it's tough to hold on or anything like that, but it doesnt seem to be like it should be.

I'm sort of worried that the engine is beginning to seize or something, but i dont really know much about that, so it may be in my imagination. I've been mixing my fuel a bit rich, somewhere between 40:1 and 32:1, so i think i'm getting enough lube. maybe i need more?

thanks for any help or opinions. let me know if you need any specific info i left out. -ryan.

Re: jerky when slowing down.

Jason Luther /

my stock maxi does the samething, i think its only the ignition missing as the engine winds down.-jason

Re: jerky when slowing down.

I am reviving this old thread, because I just had the same problem.

I have the following set up:


Metra 65 Case match

DMP stuffed crank

19mm dellerto

Tecno Estoril

This issue started after I put on the the kit. May have been an issue before, but I never noticed it.

SOLUTION: New points. I installed new points last night and the problem went away.

Re: jerky when slowing down.

ive also read that in regards to tuning the phbg carbs, if youre bogging while accelerating through the midrange you're running rich in the mid, and if you bog while slowing down, you're lean in the mid.

then adjust your needle accordingly.

i read this a while ago but ive never experienced a bog while slowing down, which is probably good if it means lean-ness.

Re: jerky when slowing down.

Or upjet, you aren't getting enough gas to ignite the mixture, so the engine slows you down. Its probably cause you have so much oil in the gas... It reduces the gas's ability to combust.

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