Puch Maxi rebuild

Maserat Maserat /

So I forgot that I was 51 and thought I was 15 again. I had a Puch Maxi as a 15yr old and had a blast with it so when a co worker told me he wanted to get rid of one I decided to buy it. It's a roached out 1984 that runs well but it had a dragging noise so I opened it up and found that one of the crank bearings is toast.

I want to know if you guys have built one that will hit 45 to 50 mph (poking around it looks possible) but I want it to be reliable and not have to constantly repair it. So I'm looking for suggestions on what parts you have used and found reliable but fast,

any suggestions will be greatly appreciated.

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Re: Puch Maxi rebuild

Brandon Weiss (Detective brandon to you) /

Welcome!

A basic 65-70cc cylinder kit, a needle bearing crankshaft, an exhaust, a 14mm bing carburetor, and a 16-17 tooth front sprocket will get you there! A basic 45mph e50 kitted maxi is one of the most common setups out there, and for good reason. There's tons of aftermarket, and they're easy to work on and reliable. Add new tires and cables to your list too!

If you tell us a bit more about the type of riding you'll be doing, making accurate recommendations will be alot easier. Rider weight, riding environment, and budget would help establish a baseline.

In the meantime, scroll up and click "Flat View" if you haven't already, and do some reading in the wiki! There's a detailed guide on rebuilding e50 engines in there.

And post some pictures of the bike!

Re: Puch Maxi rebuild

Hell yeah, I hope I'm still messing with mopeds at 50!!!! Welcome to this forum

There are a million different combinations of cylinder kits, pipes, carbs, ignition, etc that you can put together and achieve what you are looking for. It's actually kind of insane how many parts are available for Puch e50 engines. In my experience, 50mph is about the cut off before you need to start pushing the limits of reliability, so what you want is feasible.

With mopeds, the simpler the more reliable. So i would say go with a piston port kit. No reeds to fail, and less potential for air leaks. 45mm Treat 70 kit is a bullet proof single ring kit and unported you can hit 50. Treatland also sells machined heads to match this kit, get the o ring one and you'll never have a leak.

Going to need a better crank too, Treatland has nice unstuffed ones.

The stock Bing carb that comes on Puchs arent the worst, but 50 might be a stretch unless you bore it out. If you decide to buy a bigger carb, dont get another bing though. SHA carbs are very simple and depsite what some Puch lovers say, they do work great on an e50. #7 slide is the key though. 15 or 16mm will do, they make an intake for them that bolts onto the Kstar cylinder. Any bigger is kind of overkill for what you want.

Pipe, maybe something like the MLM peoples pipe. Homoet 6p is a great pipe too for small carb high revving set ups.

Stock bosch points are reliable if maintained. Set your gap, you can rotate the stator to advance the timing if you kit it.

As for gearing, you should be able to hit 50 on a basic set up like I described with 17x45 gearing. That is a nice blend of low end and top end on a kitted e50.

Re: Puch Maxi rebuild

Oh yeah, and regardless of what setup you go with... definitely get a head temp gauge!!!! It will save you from seizing a brand new kit.

Re: Puch Maxi rebuild

Chöschi21 C.K. /

Everybody is always talking about seizing a kit and having to use a Head temp Gauge, why? Seized one cylinder because of going far to lean with to much compression, never used a temp gauge, even when revving 11'000@35mph with a Squishgap of 0.8mm i didn't have any problems.

Re: Puch Maxi rebuild

Bolts come loose, gaskets fail, things happen and an air leak can occur. I'd rather spend the $40 on a gauge and have the piece of mind. It's such a simple thing to install and use.

Also, you can fine tune your bike even better with a gauge. You might be getting 35mph out of your bike now, but how do you know it cant run leaner and hit 38mph? How do you know you are at optimal operating temp? A gauge will let you safely push the limits. Not saying you need one, but there is a reason they are popular.

> Chöschi21 C.K. Wrote:

> -------------------------------------------------------

> Everybody is always talking about seizing a kit and having to use a Head

> temp Gauge, why? Seized one cylinder because of going far to lean with

> to much compression, never used a temp gauge, even when revving

> 11'000@35mph with a Squishgap of 0.8mm i didn't have any problems.

Re: Puch Maxi rebuild

Chöschi21 C.K. /

Yes they can, and yes they can, but they don't if you do maintenance. I know i can run Leaner and hit 38, but i will loose Power, it's called trial and error, i tune so that i have the right amount of power when i need it, and i don't need 3mph if i loose 5 at a hill. How do i know when i am at optimal operating temperature? I don't, and i don't care, why should i? i know that i can push it after 1-2 Miles, thats enough.

Why should i run 10° Hotter if i don't gain power with it? I pushed limits, many times, but i don't need a Temp gauge to do so, i don't even know anyone in person that uses them, i can outrun 50cc Motorcycles at a hill with my Supermaxi Cylinders, 1 Gear vs 6 Gears and 8hp.

Re: Puch Maxi rebuild

Considering the fact that you've never used one, nor do you know anyone that has one, you really can't comment on their usefulness.... but it's probably just easier to say YOU'RE RIGHT :) Glad to know we have some pros on the forum!

Re: Puch Maxi rebuild

Chöschi21 C.K. /

Can't be that useful if i never needed them for tuning, i have an Infrared thermometer but never had to use it for tuning.

Edit: i am not saying that it's useless, it might help someone that just starts, but for me i don't see a point in using it, same with Tuning smaller carbs, i just tune them by feel, no need to check the Plug or things like that.(edited)

Re: Puch Maxi rebuild

i'm not a huge fan of measuring CHT personally but when you first get into tuning its a nice thing to have. Usually by the time your first trail tech battery dies or breaks you know enough to not need one, haha.

to answer the OP's question, yeah 45 or 50 is pretty do-able on a basic reliable build.

#1 replace the crank and all bearings/ seals in that motor. hard to tell from the pic but that crank looks rusty like it had water in the bottom end at some point

#2 echoing what others have said a pretty basic 70cc piston port kit will be the easiest best way to go, lots to choose from but the kstar and metrakit are probably the two most fool proof choices at a good price point. The TCCD are a little more touchy and I've never built the super cheap airsal, but i've heard folks having odd issues with them. The malossi 62 is really really nice and if money isn't an issue that is probably the best one out there of all of them. Good torque and practically tunes itself.

#3 complete the setup with carb and pipe, once again lots of good choices but certain combos compliment themselves. the pipe will have as much if not more to do with the way the bike rides than the kit. If you're keeping it simple and going for realistic performance expectations the proma GP is a great choice for low end, proma circuit gets you a little more mids and tecno estoril probably best all around with some size complications.

a good way to get setup for the first time is find someone who knows what they are doing and straight up copy their setup even down to the jet. From there you can fine tune but for these simple setups its not too hard to go right to a running bike by just doing a pure cookie cutter of a good setup.

Re: Puch Maxi rebuild

Dirty30 Dillon /

38 mph is really not asking that much, considering I have seen a stock maxi n do that.

I use temp gauges all the time, it's really not that large of an upset in cost to not have a direct readout of your engine health.

Re: Puch Maxi rebuild

Chöschi21 C.K. /

Its not that much, but i have to tune differently were i live, i couldn't pull of a 50cc Setup with 15:40 Gearing, it would be impossible getting up hills Nicely, right now My 65cc Airsal Maxi has 12:45 Gearing and goes 35, up the hill that i ride up regularly (marked with 28%, Realisticaly about 22% over 100 Meters) wich i can get up at a little under 30mph, a Stock 2hp E50 Maxi can't even get up there at walking speed without having to pedal, so yes, i tune for Low end and Gear Short, no way i am going to go higher than stock gearing on an e50(13:45), Za50 or Z50 maybe, but probably not.(edited)

Re: Puch Maxi rebuild

Maserat Maserat /

Thank you, yes I did use that guide to diagnose the noise and to take it apart, very useful and great pics. I'm not sure how crazy I want to get with it so for now I'm going to start adding up parts. The whole bike needs freshening up but I'm going to start with the engine. A lot of great helpful responses, I love this forum.

Re: Puch Maxi rebuild

Maserat Maserat /

Thank You! A lot of great helpful information!

Re: Puch Maxi rebuild

Maserat Maserat /

Thank You! Yes the crank is crusty and will get replaced, you gave me a lot of great info!

Re: Puch Maxi rebuild

Maserat Maserat /

Never too old to play with motorized things, I put a Chinese motor on a mountain bike which was fun for a while, always in and out of motorcycles of all types, currently have a cr250f and now a Puch to play with.

Re: Puch Maxi rebuild

> Graham Motzing Wrote:

> -------------------------------------------------------

> The malossi 62 is really really nice and if money isn't an issue that is

> probably the best one out there of all of them. Good torque and

> practically tunes itself.

Graham would ya be into making me a couple Malossi 62 heads? I've got a pair on matching ZA maxis and I love em!

Re: Puch Maxi rebuild

What everyone else said, definitely replace your bearings and seals. Deck/sand-flat your case halves to ensure an airtight seal. Also look into what gearing your going to run and get some stiffer clutch springs because your take off will most likely need them.

Re: Puch Maxi rebuild

Maserat Maserat /
puch1.jpg

Re: Puch Maxi rebuild

> Maserat Maserat Wrote:

> -------------------------------------------------------

>

Looking good. So you’re a Snap-on man like myself too.

Re: Puch Maxi rebuild

Maserat Maserat /

Thank You Moped Army! So much good information here.

I have finished my restoration and here's what it looks like now.

I'd also like to say thanks to Treatland for all the parts and American Dry Stripping & Xtreme Coatings in Milford CT for the great job they did with the media blasting and custom 2 stage powder coating.

Puch11.jpg
Puch2.jpg
Puch.jpg

Re: Puch Maxi rebuild

> Maserat Maserat Wrote:

> -------------------------------------------------------

> Thank You Moped Army! So much good information here.

>

> I have finished my restoration and here's what it looks like now.

>

> I'd also like to say thanks to Treatland for all the parts and American

> Dry Stripping & Xtreme Coatings in Milford CT for the great job they did

> with the media blasting and custom 2 stage powder coating.

She came out great! how fast have you had ouit of her so far?

Re: Puch Maxi rebuild

Maserat Maserat /

Adam,

Still playing with it but only 33mph. The gearing is 15/45 not sure but I think its the pipe, pulls good uphill but flattens out.

Re: Puch Maxi rebuild

Overpriced Parts /

> Maserat Maserat Wrote:

> -------------------------------------------------------

> Adam,

>

> Still playing with it but only 33mph. The gearing is 15/45 not sure but

> I think its the pipe, pulls good uphill but flattens out.

That’s worse the stock 2 hp gearing @16x45, go 18x45 which is = to 16x40

Proma pipe pulls hard on the low and mids but flattens out real quick

Re: Puch Maxi rebuild

Maserat Maserat /

Thanks Adam,

I'll try the gearing change, I'm a little leary because I live in a hilly area, I was also thinking of trying a pipe that will give more top end but for now just the gearing. I'd like it to at least hit 40 and still pull uphill.

Re: Puch Maxi rebuild

Chöschi21 C.K. /

What Setup are you running? 33 with 15:45 seems very slow for a kitted Puch.

Re: Puch Maxi rebuild

Brandon Weiss (Detective brandon to you) /

Beautiful paint job.

Re: Puch Maxi rebuild

> Brandon Weiss (Detective brandon to you) Wrote:

> -------------------------------------------------------

> Beautiful paint job.

killed it on the paint job!

Re: Puch Maxi rebuild

Maserat Maserat /

> Chöschi21 C.K. Wrote:

> -------------------------------------------------------

> What Setup are you running? 33 with 15:45 seems very slow for a kitted

> Puch.

I installed a unstuffed race crank with bearings, a treats party 70cc piston and cyl, a treats touring head, 15mm bing with 79 main jet, I used an o ring to stop the bing to manifold leak, treats #1 grandpa manifold, high flow air filter, all new bearings and seals, matched the case ports to the new cyl, Proma Circuit pipe, for timing I had to dremel the stator to get it down to 17 degrees, I used a dial indicator to find tdc. Any advice will be greatly appreciated!

Re: Puch Maxi rebuild

Maserat Maserat /

> Brandon Weiss (Detective brandon to you) Wrote:

> -------------------------------------------------------

> Beautiful paint job.

Thank You, American Dry Stripping & Xtreme Coatings did a great job with the powder coating, I was going to paint it originally but their price to strip and powder coat it was less that just the primer and paint alone forget about all the work to strip it manually.

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