puch won't start

my puch won't start. ive checked for everything i know of. great spark, clean carb with everything properly installed, exaust not clogged. i let it sit for about a month. then took it out on a ride for about 30 minutes, then it started to backfire and finally shut off. now it doesn't start up at all. is this is a jetting issue?? ive been running it on a 58 for months and it was running great, now all of a sudden this happens. anyone have any ideas?

Re: puch won't start

Smitty Smith /

I normally contribute backfiring to an ignition / timing issue.

You say it has good spark...what color is the spark (yellow, red, blue?). What color is the insulator at the plug's electrode?

I'd check plug gap, and points gap and condition. Also, being a Puch, the horn most of the time is wired in such a way that if it is unplugged, or the horn switch is not properly grounded, or even if it blows a tail light bulb, the plug won't fire.

Hope this helps, and I hope you get it running again soon.

Re: puch won't start

Shawn Eubank /

the spark is blue and the insulator is a brick red color. the plug gap and points gap are correct and the horn works when i turn the engine over along with the taillight and headlight. im going to try adjusting the gap and messing around with the jetting. could my timing be so off that my piston isn't hitting the plug, so that no gas is combusting at all??? how do i check for this?

Re: puch won't start

brick red indicates water in the gas...flush the tank out and carb and replace with fresh gas.

Re: puch won't start

Shawn Eubank /

done. still no better. im gonna try to adjust the timing. how do i go about doing that?

Re: puch won't start

if there was water in the tank the carb might be a bit gummed up, i'd keep looking at that

Re: puch won't start

I always have to replace my plug and then my puch fires right up. replace plug. replace plug. new. new. new.

Re: puch won't start

Smitty Smith /

Have you changed the timing? The timing doesn't normally change on it's own. People, think for a minute, if the timing doesn't change itself, then what makes you think that changing the timing is going to help??? Look at and perform the obvious FIRST! Change the spark plug, and check EVERYTHING else before monkeying around with something, just because!!!

It is quite often the small obvious things that elude us.

Re: puch won't start

Smitty Smith /

When I said timing in my first reply, I should have noted that the point gap may be dirty or worn, and in need of cleaning, as this would disturb the timing.

I don't suggest just changing the timing by moving the stator, if the bike was running, but now isn't.

Backfiring can also be an indication of an airleak somewhere. Check the cylinder to case, intake to cylinder, exhaust gasket, head nuts for proper torque, etc.

Another possibility would be a crankshaft seal leaking.

Re: puch won't start

Shawn Eubank /

i got it started! i just popped a new spark plug in and it fired right up. i still don't understand it but hey, it works now. can a plug be fouled and still spark? if so, i guess that's what happened.

Re: puch won't start

go figure...the simpliest thing was the problem. yaaa for smitty LOL!

Re: puch won't start

Smitty Smith /

LOL!!! I've pulled bran-new plugs out of the box and they turn-out to be bad. I've also encountered an issue like yours, and was told that a plug may fire outside of the head, but may not fire under compression.

Sometimes it's the simplest little cheapest bs things that stump the mud out of us at times, LOL!!! Glad to hear you got it running, way to go!!!

Aren't you glad you didn't go fiddling with the timing now, LOL?

Re: puch won't start

steveintoronto /

yaa for mopeds!!!

diabolically simplistic.

Re: puch won't start

Some kind of gas problem...Im having one too with my jawa

Re: puch won't start

steveintoronto /

this reminds me of a moped memory i have from last summer. my bike was running terribly: the horn broke; the lights killed the engine; it was a pain to start, and it sputtered when it did. wanna know how i fixed it? i washed it with a soapy sponge and changed the oil and everything ran perfectly..... for about a week.

i think there might be fine print in all of the moped owners' manuals that says: "something on this bike will remain broken or dysfunctional at all times. get used to it!"

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