79 Puch Maxi Trouble

I've got a 79 Puch Maxi. Ran it all last year without any major trouble. When I started it up this year, it was having some trouble.

Couldn't get it over 25 and would stall out occasionaly for the first 5-10 minutes. It wasn't running great, but it was running reliably.

We (Brett Dan Russ and I of 50:1) took the carb off one night to try a bigger jet, make sure everything was clean, etc. to see if that would improve the performance. Tried a bunch of different jets, swapped out spark plugs, no luck. Put it back together the way it was, but then it wouldn't run at all. Sometimes it doesn't catch. Sometimes it does, and dies out immediately. Sometimes it will idle and you can give it gas no problem. When it does get running, and you give it gas, it will go strong for a bit, drops out occasionally but will come back. Eventually (usually pretty quickly) it dies off.

To date we have redone the wiring hub, clipping the ends and stripping fresh wire, put in a new condenser, put in new spark, put in new points, checked the compression, and cleaned the carb a billion times. Still behaving the exact same way, the only difference being that when it does run now, it runs much better than before we did all this.

The points and the timing seem fine. Fuel flow is fine. My gas tank is nasty, and I don't have a filter in my fuel line, but I don't think this is the problem. I will add a filter and clean the tank out tho.

We're pretty sure it's an electrical problem. We have checked the spark and seen it firing strongly and regularly. Then we put the spark into the cylinder and try the bike a few times. Take the spark out again and it doesn't spark or sparks intermittently. We've checked the wiring on the boot and it seems fine. One of the weird things is, when the bike idles pretty well for a while, it dies out when I get on it. Spooky.

Any Puch electrical gurus out there with advice?

Re: 79 Puch Maxi Trouble

Ben Van Zoest /

You goto wash out the carb and needle tube, most likely u have a fuel delivery problem...

Re: 79 Puch Maxi Trouble

Have cleaned the carb and needle, there seems to be no problem at all with the fuel delivery...

Re: 79 Puch Maxi Trouble

i have the same problems w/ my maxi (81) and found out yesterday that one of the rings was no good so a new set is on order and hopefully that will work

Re: 79 Puch Maxi Trouble

Try swapping the spark plug holder (it's called something else but I can't remember the name right now) with one that you know is working. This was what was wrong with my 80 puch that drove me nuts about a month or two ago. I think the holder is insulated and has a set resistance (1k ohms?) which can break down and wreck your spark.

Re: 79 Puch Maxi Trouble

Ben Van Zoest /

Ditto here, nasty problem, at any indication of spark failure weak or occasional spark replace the OEM (metal) spark plug cap. I got one from a old lawn mower all plastic worked right away!

Re: 79 Puch Maxi Trouble

Ok, will try this out.

Re: 79 Puch Maxi Trouble

We tried replacing the spark plug boot, but didn't matter, we replaced the high tension coil, but didn't matter. we have a new condenser that needs to be soldered in. It is really strange, especially the stalling when you get on.

Re: 79 Puch Maxi Trouble

Ben Van Zoest /

Tail running lamp may have poor contact, make sure lamp is seated w/ clean contacts. Broken filament???

Re: 79 Puch Maxi Trouble

good point, the tail lamp is shotty

Re: 79 Puch Maxi Trouble

man we did never look at the taillight, and if i remember correctly, that entire thing was hanging on by a thread when we first started to have huge problems

the rings should be fine, its got 150 psi,

Re: 79 Puch Maxi Trouble

It could definitely be the taillight, it's pretty stove up.

Re: 79 Puch Maxi Trouble

Wait, it's what?

Re: 79 Puch Maxi Trouble

well i dont see logically how it could be the tailight, as i have riden a few puchs without tailights, infact when i was working on my tailight the other night, i just had bare wire hanging down and the bike still ran, however i do remember when you first broke it Russ, that his tailight was hanging down,

on some minarelli powered bikes if the tailight bulb blows, then the bike wont run, however thats usually not the case with puchs, if the horns not connected or the horn wires are messed up you would have problems but not the tailight

at this point i am willing to give anything a shot

if it isnt running in a week, we'll toss it in the east river

Re: 79 Puch Maxi Trouble

Ben Van Zoest /

I still think you got to have a working rear 'run' lite. the LAW...

A defective horn also inhibits ignition. You can tape the two horn wires together I had too once and left it so.

Threw away the horn, it was no good.

Re: 79 Puch Maxi Trouble

The horn has been funky in the past as well, sometimes it comes on when I turn the lights on, so that is worth checking.

Re: 79 Puch Maxi Trouble

Maybe I am a little green to the world of electirc systems, but how does the tail light dictate if the ped will run? Just curious...

Thanks!

Bill

Re: 79 Puch Maxi Trouble

Many Puch's are wired through the tail light and the headlight. If one of those conections goes bad, it doesn't run. Safety feature, I guess.

Re: 79 Puch Maxi Trouble

Update:

The horn/headlight wiring was the culprit. Fixed that up and she's running like a champ! Well, did for about two hours.

It's definitely a fuel flow thing. Electrical is fine, with the exception of my ignition switch not working at all. Spark is strong and consistent.

If I clean the carb out, she runs well for a varying amount of time usually not long, then will start bogging down, backfiring, and stalling out. It gets progressivly worse, til she doesn't recover from the stalls. I had her out for about a 1.5 mile round trip, got home just as she died completely. I immediately pulled the plug and it was bone dry. Clean the carb and the process repeats itself.

I figure the tank is super nasty and is the cause of the trouble. I used some concrete cleaner in the tank to clean it out. Hopefully it was the right stuff. More on this in a sec. I soaked the tank for 20 minutes or so, then flipped the bike so it would soak the top of the tank. After flipping the bike, it took me a couple minutes to locate the slow drip I was hearing. Dark reddish brown oil was dripping from the engine into the body of the bike and out the seat mount. I flipped the bike over immediately. I probably lost about an ounce or so of fluid. Anybody know what this was? I'm afraid to start the bike without knowing what it was and if I should replace it.

When I drained the acid from the tank, I was worried. I was expecting it to come out like liquid death with chunks. It was only light brown though. Drained it all out and started hosing the tank out, again the water was not as nasty as it should have been. After rinsing a bit, I let it drain out and tipped the bike over to get the last of the water out. Nothing was coming out, but I could still hear water in the tank. Hmmm. Tilted the bike way over and shook. Sweet Cuppin Cakes. I found the Chunky Death Nuggets. Spent the next half hour shaking out the Nastiest Stuff I Have Ever Seen. Chunks half the size of my pinky nail. Something long and squiggly and LONGER than my pinky.

Hopefully this will help, but I will definitely need to do this again, maybe with a stronger acid. The bike is going to dry out over night, then I'll try her tomorrow. Any ideas about the stuff that leaked out? I don't want to fire her up without knowing if I might damage the engine.

Re: 79 Puch Maxi Trouble

The red liquid is transmission fluid. If it is dark brown then you should change that as well. The drain in on the bottom of the engine. How you fill the tranny back up depending on if you have a 1 - speed or a 2 - speed. 1 speed there is a screw on the top of the transmission case fill it up with Type F transmission fluid. if it is a 2 - speed remove the top cap and the over fill screw on the side of the tranny cover and fill till fluid come out the over fill hole. If you did use water in cleaning your gas tank Make Sure you get every drop of water out before you ever try to fire the bike up. Pour a cup of gas into the tank slosh it around. Drain that out and repeat a few times. then let it sit and dry for a day, just to be on the safe side.

Re: 79 Puch Maxi Trouble

Been drying since yesterday afternoon and has another 5 hours in the sun or so, then I'll see if it is dry. I think this is a one speed, but not sure. Any way to find out by looking at the bike?

Thanks for the help!

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