Top End Mystery Sounds


When I pull full throttle, my Puch used to bog down (engine sound dropped & speed... four stroking, I believe).

I adjusted the needle and I can go full throttle now. Though now I have a whole new sound to deal with. Now when going full throttle, I hear this loud clanking sound. Kind of high pitch... also, I can feel my bike slowing down. It almost seems that the piston can't keep up or something. Kind of the same sound you hear when you're hauling ass & just let off the throttle..

When I let on and off the gas, the sound will go away (smooth ride).. but not always.

Is this a sign of it running too lean on the top end?

I have a Puch MKII sport (2 speed). Proma GP pipe & high air filter.

12mm bing w 58 jet. My neelde is in the 2nd or 3rd position... forgot which.

Thanks Folks.

Re: Top End Mystery Sounds

Yup,apparently that's a lean spot in your powerband.Don't run it hard up there until someone with more experience can help you,all I can do is say be careful about revving that high.

Re: Top End Mystery Sounds

Easy way to tell, put a larger mainjet in and see if the plug chop is darker. I generally try to upjet until it 4strokes, then go down one or two sizes to make sure I'm not too lean.

Re: Top End Mystery Sounds

osprey of Dee'z loinz /

what gearing are you running?

Re: Top End Mystery Sounds

Check to make sure you are not riding Dutch backwards up a hill, it might be the wood shoes clapping together at high speed! ;-)

Re: Top End Mystery Sounds

The needle is only for 1/4 to 3/4 throttle. The jet is for full throttle the high pitched noise is the piston scraping the cylinder? Or maybe an intake that whistles like mine. I say upjet.

Re: Top End Mystery Sounds

Dude that was fix!... my foot got slammed to the ground by this huge sloppy pancake.

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