puch maxi runs great until it get hot, then runs weakly at WOT until death

i probably dont need to make this, but i need to think aloud somewhere. if you have any input, let me know.

puch maxi with 65 cc mallosi, and VM 18 carb runs amazing until engine gets hot, then runs weakly at WOT until it finally dies.

i just replaced the condenser, same issue. went over intake and cleaned carb (added new tighter fitting chrome hardware and intake gasket) same issue. new plug, same issue. cleaned points, same issue. cleaned tank and replaced fuel filters, same issue. fuel flow is healthy. i am going to do a leak test later night. (with carb spray)

so what are all the reasons a bike would run very very strong and then die once it hit 300-350°F? it is extremely humid here. could my crank seals be going? i did notice some goo on spark plug that looks like oil. its not ignition timing... maybe my transmission oil seal is going? or maybe my pipe is full of goo? i am going to have to take this little dude appart tonight arent i?

What happens when ignition coils begin to go bad? i will check stator voltage and OHMS tonight, but i have the suspicion my ignition coil is failing. do they give intermitant issues when they begin to fail? or do they just flat out die?

Re: puch maxi runs great until it get hot, then runs weakly at WOT until death

Overpriced Parts /

Mikuni carbs can feel tuned right away but most people are off 70-80% off of jetting and the float level has to be perfect or it will feel like running out of gas

If you replaced the condenser and didn’t use use a original Bosch then put a original one back in the crap aftermarket ones are junk when hot

If coil is stock external those are bulletproof like Bosch condensers

If old style internal coil or the treats points Stator with the internal coil Forget about it

Do not use any of those systems

Re: puch maxi runs great until it get hot, then runs weakly at WOT until death

the coil is external.

i will check on the float level tonight. that could be it, since i did clean the carb 4 or 5 times

I haven't altered the jetting since it came from Detroit moped works. (thats who built this bike originally, so i doubt the jetting is off)

i will find a bosch replacemnet. i dont think the one i replaced was a legit bosh condencer. i also relocated the condencer on the frame. (used a bolt that screws into the original air filter holes) is this good enough placement? or do i have to mount it to the case of the motor itself?

Re: puch maxi runs great until it get hot, then runs weakly at WOT until death

Bad Cadillac™ /

Coils very rarely fail. Search here to find all the posts of people replacing them and that not fixing their issues.

Re: puch maxi runs great until it get hot, then runs weakly at WOT until death

yeah, lost spark now. i gotta find my multi meter. something is definitely wrong with the ignition system. can points just go bad? can high humidity fuck with the ignition system? (maybe condensation is grounding something out? )

Re: puch maxi runs great until it get hot, then runs weakly at WOT until death

Dan (high idle) Conway /

It very much could be the HT coil, I had an issue just like this with a hobbit that drove me nuts, changed the coil, problem solved... 2 days of my life wasted before I made that realization hahaha If you have an extra lying around it’s definitely worth a shot. And points go bad when the corrosion is so bed the contacts are ruined, or they’ve been sanded down unevenly. however I don’t see any reason points would be the issue due to failure involving heat.

call me crazy, but trans oil gets hot and viscous, I wouldn’t be surprised if it poked through the seal into your combustion chamber at a high temp. Any white smoke out of the exhaust?

Re: puch maxi runs great until it get hot, then runs weakly at WOT until death

That Malossi is a nice kit but too much dough... Before I spent any money I would put the Bing back on with proper jet and atomizer and TEMP GAUGE trail-tech... and slowly break it in a while...they do run hotter when they are new...I like to heat cycle it a dozen times or so. When it starts getting weak and boggy the temp is usually 250 - 300 + You would be surprised just how good that Malossi kit will run with a 14/15 Bing carb and a temp gauge

Re: puch maxi runs great until it get hot, then runs weakly at WOT until death

what pipe?

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