78 Puch Maxi engine locking up


I have a 78 Puch Maxi. When I ride it even now and the the engine will stop and lock up or seize up. The bike slows down tremendously and comes to a stop. I try and pull the clutch and restart it but the fly wheel won't spin free until a couple tries at it. Im unsure if its my transmission fluid getting clogged up or not. Please let me know if this explanation helps enough and what I could try, thanks.

Re: 78 Puch Maxi engine locking up

Hi Patrick, welcome to the forums. It could be many things, but sounds like it may be soft-seizing from lack of fuel/running too lean. This is not a good thing to keep doing as it damages the piston and cylinder. Take out the plug and see how it's doing. It should be a nice chocolate brown color, if it's too white it is too lean (and black is rich). It may just need a fuel system/carb cleaning to resolve. Start with fred's guide and the puch wiki:





Good luck,

~M (edited)

Re: 78 Puch Maxi engine locking up

I also have a 70 Kstar kit on it along with a 16mm carb, would that have to do with it as well?

Re: 78 Puch Maxi engine locking up

Overpriced Parts /

Ya you seized from hi incorrect timing, incorrect jetting, not running a carb with a needle, low gears with hi rpm pipe and not running a head temp gauge keeping below 400 degrees F.

Please remove cylinder and piston and post pictures to see if it can be saved/repaired because once it's seized it seizes again easier.

Once you repair your kit or get a new kit then time at 14° before top dead center, run a 14-15 mm bing carburetor or one that has a needle, run a lower rpm pipe like estroil/circuit, gear at least 16x40 and run a head temp gauge.

Re: 78 Puch Maxi engine locking up

***Kim Jong illest*** /

I could be lots of things. I thought I had seized recently until I realized I had a magnet come off the flywheel.

Also, there's not a damn thing wrong with the carb you chose. Dont let people make you think their preference is mandatory.

Re: 78 Puch Maxi engine locking up

thanks josh, I didn't think there was anything wrong with my carb and it has a needle so that shouldn't be one of the problems. The carb is a 16mm Mikuni. I have it apart right now, looks clean all around. Not sure if I just need a bigger or smaller main jet. Hell the main jet might not even be my problem. I am also running a simonini, the exhaust has not been used much with this kit( 70cc Kstar).

Re: 78 Puch Maxi engine locking up

Overpriced Parts /

Get rid of the high rpm hot running simo pipe and get a circuit/estroil unless you're going to run a retarding ignition

Re: 78 Puch Maxi engine locking up

is that really why, there was a circuit on it before

Re: 78 Puch Maxi engine locking up

Overpriced Parts /

No a lower RPM set up, pipe just runs a little cooler on a puch.

People still seize with circuit type pipes

If you time low, jet high, run lower rpm you will run cooler

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