slow puch maxi

Swapped an e50 with a new 50cc kit on my maxi to replace the za50. Runs great on the stand and starts up with no problem, but SO SLOW and no power at all. With one hand I can hold the thing back all the way revved up. So I have 3 scenarios:

1) Stock pipe (deresticted) with 14mm bing and 54 jet. This starts and revs just fine but even with pedaling it won't pull me at all.

2) Techno boss and 14mm bing with #60 jet. Have to help it to get moving, but will get me up to about 20mph. Holy crap is boss the loud.

3) Stock pipe with the 60jet. Same problem as the 54 jet. No power at all.

Yes I've played with all the needle positions and tested, changed the tranny fluid (only up to the screw) and went with and without the airbox. I changed the front sprocket to a 14T so i'm running that in the front and 40T in the back. Been at this for 2 days, and even with the boss pipe it's pathetic I have to pedal up to 10mph for the thing to start pulling on it's own.

Any help would be greatly appreciated.

Re: slow puch maxi

Norm 2 speed or 1, what year maxi is it , how is the gas flow ,? if its an old maxi ,hows the tank ? clean or full of shit ? if its an old ped the shit hides down the bottom of the tank that puch calls the reserve tank and tho the gas seems to flow clear that shit gets into everything as you jolt and bownce it around make sure the tank and carb are clean clean clean

Re: slow puch maxi

Ben Van Zoest /

Baffles me too, surely a lame upgrade, how did she run before the 50cc kit.

Re: slow puch maxi

Sorry , should have put in more info. So it was originally a'78 2 speed maxi mkII, but the 2speed transmission was hosed, so I switched in a whole new 1speed transmission and aftermarket 50cc topend, kept my old stator and flywheel to make the wiring easier.

The tank is sparkling, I spent a week degreasing, derusting, and por-15ing the bastard so gas flows crystal clear. The carb is rebuilit 14mm bing with all new gaskets, needle, jet, float, etc... Clutch is good, new points and condensor. Far as I know this thing should work. The topend is a 50cc aftermarket kit , and I do have a techno boss pipe, but i kept on the old exhaust and #54 jet that ran with the 2hp 2speed engine. I realize I need to tweak and rejet since it's now a 1speed engine (but with the kit and the high torque head, still 2hp?) but still doesn't explain why my lowend pull is so pathetic, even after switching the front sprocket from 18T to 14T. I guess I could put it back but I don't think that's the problem and would probably only make it worse.

Again, when i did slap on the techno boss and up jetted to #60, i could move up to 20mph, but take off still required pedaling, but with the stock airbox and pipe this thing can't get up to 5mph and bogs down at full throttle.

Even if it were jetting issues I still can't see it explaining why I can't get this thing to pull me off the line itself withough pedal help, I'm a big guy (200+) but I shouldn't be able to bog the engine by pressing down on the seat with one hand.

Re: slow puch maxi

One thing I can think off is that I'm just way under or over jetting. The plug comes out oily and wet at the #54 or the #60 , so I don't think it can be overjetting (though the #60 works well with the techno boss pipe, might even need a I bigger one). Could #54 be just too high? (I played with the needle settings at every level, nothing helped.)

Re: slow puch maxi

Ben Van Zoest /

A 54 is not enough 64 is more like it, airleak somewhere?

Re: slow puch maxi

for the stock pipe? #54 used to work just fine on the 2speed engine. A 1speed, even with 50cc metra kit and just a stock piped need to be upjetted? Like i said, the plug was dark and wet, which i think means too rich.

Re: slow puch maxi

if your plug is oily and wet its too rich. it should be tan colored.

Re: slow puch maxi

Nor Cal Mopeds /

heres some things you should check, make sure your piston is facing the wrong way, the arrow should point down, try filling the piston around and see if that helps. Another thing you should check is for a vacuum leak, when its running get some carb cleaner and spray it around all openings, around the carb, the intake manifold, the head/base of the cylinder, the exhausy port, and ESPECIALLY around the throat of the carb where it meets the intake mainfold, if you found a leak by your carb use some TFE teflon paste and put it on the inside by where the intake mainfild goes into, those bings get streched out really easy, and that is a common issue, and usually if it bogs its too lean and needs more fuel, so just for kicks try upjetting more than you would think.

Re: slow puch maxi

Nor Cal Mopeds /

wow, "make sure your piston is facing the wrong way" sorry I meant facing the right way obviously, my bad.

Re: slow puch maxi

Norm not for nothin but I only way 140 and mine has a hard time getting going ,no slam guy but something to think about ,Of course you said it wont go any faster than 20 when it does move so maybe you have a clutch problemo Peaceup Dan

Re: slow puch maxi

That one speed clutch is a real weak sister ,when you hold it back by pushing down on the back tire does it rev up or bog down like it wants to move but cant Peaceup Dan

Re: slow puch maxi

you've tried with and without the airbox, have you tried a middle ground? knife+plastic bottle+ foam+ masking tape= speed. at least for my puchs anyway.

Re: slow puch maxi

bogs , doesn't rev, no offense taken on the weight, I know i'm big for a one speed, expecting to need some help getting off the line, but still doesn't explain the piss poor top speed. Plus I thought dropping from a 18T to 14T front sprocket would make up for it a little.

Going to the carb spray test this afternoon, see if I'm leaking anywhere. Piston is installed right so isn't that.

God i want my 2speed back.

Re: slow puch maxi

🇮🇹💦 Of the Loin /

im pretty sure that a #64 is a stock jet for the 2hp maxi so it sounds like something else is amiss

Re: slow puch maxi

Try Just taking the tube off the back of the airbox

Re: slow puch maxi

so I tried the carb spray test, no problems anywhere, though when I sprayed the manifold/carb junction, the bike slowed down, did not speed up. Clutch wasn't too tight.

I planned on playing with the airbox/pantyhose ideas, but I don't think this is the underlying problem. Being too rich or getting too much air still doesn't explain why I can't get more than 5 miles our with the stock pipe(does it). If I was getting 20mph then I could see the tweaking making up the difference, but doesn't explain this.

because the bike will go 20 with the prf exhaust on it does this mean that I need a 48-50 jet (as opposed to a #54 which came stock). is #54 (at all needle levels) just so rich the stock pipe (deristricted) just can't keep up with expelling from the carb?

Re: slow puch maxi

you have way to many variables,

you need to put together the bike, as you want it, with one pipe, and one carb, all this switching around of carbs/jets/pipes/gearing is sort of like hearding cats

put the techno boss on there, make sure you have a good seal with the exhuast gasket, you can put your hand under there when the bikes runnings, and feel for an air leak, you should have none

test for compression to make sure you have no head/jug leaks, make sure all the top end gaskets are secure, i dont know what that kit should run, but probably somewhere around 150, at the least, i would imagine, anythying less than 120-130 could explain somethings

do you have a stock airboox? put that on to break in the kit, then get a bunch of jets, from low 60's to mid 70's, if not higher, and start with the largest and work your way down untill you have good throttle response, no bogging or four stroking or anything, you should be abble to open the throttle without any ill results

make sure your points are opened to .018, and your timing is set at least remotely right

keep your oil to gas ratio consistent, something like 40:1 for the kit, whats your ratio now?

if your plugs are looking oily and dark,, it could be because the needle setting is the richest, this effects the idle, and coiuld cause your plugs, although potentially looking lean at full throttle, to darken down at idle

i think a large part of your problem is jetting, 50 size jets seem way to small, and you could also have an air leak somewhere,

Re: slow puch maxi

thanks bret. I think I'm going to give it up for this weekend. Ordered a mikuni from smitty which I think is a better match for the topend kit. I would stick with the boss pipe, but that thing is loud, seriously I have to wear earplugs when I'm working with it, hurts to stand next to it.

So next weekend I'll start with a the mikuni, stock air box, and deristricted stock pipe and see how that goes. I'm also going to switch out my 2.5 inch gazelles and put on some 2.25 inch slicks, anything to remove weight and get this thing to some working baseline. I'm pretty sure I have no leaks, on either pipe, but you're right I have too much going on right now to be able to nail down a problem.

One thing though, when I try it agian next weekend, should I stick with the 14T front sprocket or go up to a 16T or 18T? I can't think this would help my power problem, but I'm willing to try anything, even drop down to a 12T.

Re: slow puch maxi

i would stop messing around with things that wont really solve the problem, tires and sprockets arent the problem

however i would break in a new kit with a top end gear combo, something like 16x40 or 42 minimum, that way you minimize friction in the top end,

the pipe shouldnt be that loud, are you 100% positive you dont have an air leak around the exhuast header?

Re: slow puch maxi

you know I'm not sure, that would explain why it was so loud, I knew it would loud with an prf pipe, but it did sound almost as loud as having no pipe on. I'll go with the 16T to break in like you suggested, and get a new exhaust header gasket, mine's a little chewed up.

Re: slow puch maxi

Ben Van Zoest /

That tells all, the engine isn't getting enough back pressure (echo) from the unrestricted exhaust pipe my feeling is. whereabouts you live Norm.

Re: slow puch maxi

I'm in cambridge, just across the river from boston.

Re: slow puch maxi

you should go see Fred or Joe the Ho, they could help you out

Re: slow puch maxi

Cleats Onionpockets /

Something's definatly up with your setup. I got your email, but didn't read this post before I replied. You have the potential to run mid thirties with that setup. Mine is set up with the stock cylinder, minus the ase and head gasket to increase compression, a bosch platinum spark plug, a stock 12mm carb, a 70 jet, a high flow air filter custom built, and the same techno Boss exhaust. I'm running 14-40 gearing, and I have no problem hitting between 30-33 on the flat. Granted, seeing as I'm a heavy guy (250 lbs on a good day) it takes a few moments to get up to speed, but it doesn't take forever, and I CANT hold mine back by just holding the seat with the throttle open. Something is screwy with your settings. The smaller jets will solve the richness problems, but if you want to add power you should probably come up with a better air filter. Autozone sells breathers for car transmissions that can be adapted for the purpose nicely.

Re: slow puch maxi

I have a puch maxi luxe with the 1 speed 2hp engine with a stock pipe stock carb and stock motor i have a #66 jet if this will help you basically the same motor setup as you but on a maxi frame

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