Puch Maxi Luxe fun fun fun

Hey everybody, I've got a couple questions and thing i'm dealing with on my 78 Puch, figured i'd throw them out here and see if anyone had any expertise.

yes, I've consulted Freds guide, before that comes up.

So its got a high compression 70cc kit on it, and for a while with marginal effort would start and idle, albeit not very well.

Lately she just wont start. Got really high compression ~190psi, spark is good, gas is getting to the carb. Gonna take apart and clean the carb today but i have doubts thats the culprit.

Sometimes it starts super easy, a quarter pedal and off she goes. But its super inconsistent.

That said i have two, stranger questions. First off: how hard is it supposed to be to turn the engine over? If i'm pedaling the bike and engage the clutch 2/3 times it will just stop the bike, 1/3 of the time it tries to go but doesnt. I can only ever start her up on the kickstand. Sometimes when the clutch engages i can stand on the pedal and jump without getting it to turn over, i'm a big guy too.

lately the clutch has been slipping more and more though, i'm changing the fluid today but i dunno, i'm wary.

The last thing is occasionaly when the brake light engages, all the lights dim and the bike dies. Which is weird because other times the 12v bulbs i have in her glow si bright they look like theyre gonna explode the way the 6v ones did.

Thanks guys

Re: Puch Maxi Luxe fun fun fun

first Q, e50 or za?

which kit?

how does it crank with the plug out?

i aim for 135 to 165 psi cranking, because i'm noob.

did you rebuild the bottom end, or just kit it?

you wrote "Sometimes it starts super easy, a quarter pedal and off she goes."

do you mean it pedal starts with low effort, or fires off when you're able to force it 1/4 kick?

cart and horse, do the lights dim because the idle drops, clutch, or they dim and the motor wants to die, despite throttle, electrical.

Re: Puch Maxi Luxe fun fun fun

Overpriced Parts /

Not timed, jetted or tuned correctly.

If kitted to 70 cc and not timed or jetted correctly you may have a seize or piston/cylinder damage. Shame you didn't get a stock unmolested bike now it's gonna take forever to get your bike running perfecto.

You're going to have to list your complete set up

Engine, intake, carburetor, jet size, timing setting, air filter, exhaust pipe brand/type, gearing, head type,

Re: Puch Maxi Luxe fun fun fun

>first Q, e50 or za?

e50

>which kit?

dunno, came this way from the magiclands of craigslist

>how does it crank with the plug out?

marginally better I think, cant remember, will check

>i aim for 135 to 165 psi cranking, because i'm noob.

If i had my choice I would too, but this is how she came

>did you rebuild the bottom end, or just kit it?

looks like it was just kitted

>you wrote "Sometimes it starts super easy, a quarter pedal and off she >goes."

>do you mean it pedal starts with low effort, or fires off when you're able >to force it 1/4 kick?

both actually. Little effort, and a quarter rotation of pedal and it goes

>cart and horse, do the lights dim because the idle drops, clutch, or they >dim and the motor wants to die, despite throttle, electrical.

despite throttle, brake light is only wired to front brake so even if i apply brake with the back wheel spinning free it tries to kill the moped. That said my lights do dim considerably on idle independent of brake application

Re: Puch Maxi Luxe fun fun fun

>Shame you didn't get a stock unmolested bike now it's gonna take forever to >get your bike running perfecto.

I agree but i took what i could get, its in good shape otherwise, looks like i just have to put in the effort to get her reliable

>You're going to have to list your complete set up

>Engine, intake, carburetor, jet size, timing setting, air filter, exhaust pipe >brand/type, gearing, head type,

Ok so i'm not positive because I didnt do the mods, and i'm at work currently without access to the bike but looks like the e50 engine, a metal mesh high throughput intake (from treatland it looks like, kinda jury rigged on there), stock bing carb, dont know the jet size right now, dont know the timing, aftermarket exhaust... its a proma, interferes with pedal clearance.

Work is heavy at the moment but i hope to get the carb and timing worked out real soon. Any suggestions on jet size and timing. is 17 degrees acceptable with the high compression 70cc? and at .4 mm gap for the spark? or is that bad news. I dont really want high end power at the moment i just want usability. Power comes later.

As far as piston damage at least I checked and its not crashing the spark plug (got the shorties in there) It holds compression (really high compression?) so that would suggest the seals are ok... When it does run no terrible screech or clank, wee'l see how the tranny fluid looks soon enough...

Re: Puch Maxi Luxe fun fun fun

Dim lights at idle is normal, rear brake light could be shorted out, some motors depend on rear light to work to run. Some mopeds have a switch under the head light to by pass the tail light

Re: Puch Maxi Luxe fun fun fun

It's going to be really hard to kick it over with that kind of compression. It will be easier to bump-start, or get on and pedal till the rear wheel has enough inertia to overcome the flywheel and compression when you engage the clutch on the down-stroke.

How thick is the base gasket and is there a head gasket installed (you should be able to see the edge of both)? You could add a thicker one, or use a lower compression head.

Is the ignition and the rest of the wiring (lighting system etc.) stock? Sounds like it may have been re-wired. On a stock system the ignition, head, tail, and brake lights all run off different coils and are essentially separate, so your lights should not dim unless there's a short somewhere. The ignition is tied in with the horn, so that has to work or be grounded at least. I would go over the whole system from magneto out so You know what You're dealing with. Here is the Puch wiring wiki for reference;

http://www.mopedarmy.com/wiki/Puch_wiring

And this pdf lays out, separates and explains all the circuits (probably the best moped teaching aid ever created); http://www.mopedarmy.com/mediawiki/images/1/1a/1977_Puch_Maxi_Wiring_Diagram.pdf

You also need to download the puch repair manual and at least skim it and read about the electrics.

Go over the basics. You need to know what carb and jet is on there, as long as it's reasonable and you have spark and compression it should run. The only other thing is timing, which you should back off to 14-16° or something dumb like clogged exhaust etc.

GL!

~M (edited)

Re: Puch Maxi Luxe fun fun fun

Thanks, it seems like its a simplified wiring, though not exactly the simplified wiring diagram suggested on MA (real close though).

I'm gonna work on the basics this weekend i hope, How would I check for an exhaust blockage reasonably? any tricks?

Re: Puch Maxi Luxe fun fun fun

No clean way to go about it, when it's running you can kind of judge by how much exhaust is coming out. The stock pipe you can take it all apart to clean the baffle, not so much a problem on performance exhausts.. Can always just try to start it with the pipe off, but don't go riding around like that.

gl

~M

Re: Puch Maxi Luxe fun fun fun

to clarify:

1: hard to start, could just be the compression, slipping clutch.

i'll let others discuss, including starter clutch shimming issues.

you made it sound like it's still hard to pedal with the plug out (hope to hell not)

2: intermittant no start, range of options there.

3: electrical snafu, brakes are interfering with spark?

sounds like dealing with 3 could fix 2.

i'll take snafu for $400, alex.

Re: Puch Maxi Luxe fun fun fun

check your horn and back lights. if horn is not working puch will not start and also if brake light out will not start, try new light blubs in back.

Re: Puch Maxi Luxe fun fun fun

OK quick followup time

Cleaned Crab, cleaned electrical contacts, re timed, gapped sparkplug.

starts good, runs real rough but we will work that out.

New goals are get her running smooth and get these damn headlights brighter

both running 6v bulbs

both barely even oranging the filaments

Re: Puch Maxi Luxe fun fun fun

Check ground from light coil.

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