1977 Puch Maxi - Bogs at full throttle

Its beautiful outside today!

So I'm working on a 1977 Puch Maxi 1hp. It runs and idles but when I give it full throttle it bogs down. If I take off the air filter and restrict the air intake half way it will run great.

Do you think it has to do with my air filter? Could my jet be the wrong size?

The fuel flow is fine and the carb is cleaned out.

Any suggestions?

-Rob

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Re: 1977 Puch Maxi - Bogs at full throttle

Also, how fast are these stock 1hp's supposed to go? Right now it tops out at 19mph on a flat.

Re: 1977 Puch Maxi - Bogs at full throttle

You should be going faster, even with a 1HP engine.

Could be either of those things. What jet are you currently running? Have you looked at your plug?

Re: 1977 Puch Maxi - Bogs at full throttle

The 1HP. only go about 20 anyhow, try a jet 2 sizes up from what you have .

Bob

Re: 1977 Puch Maxi - Bogs at full throttle

is the spark plug fouled?? perhaps the piston could be dirty? maybe it coule just be an air leak, or exhaust leak or something. the bike looks really nice by the way. its gotta be something small. ..

Re: 1977 Puch Maxi - Bogs at full throttle

Ben Van Zoest /

Way to much slack in the drive chain..

Re: 1977 Puch Maxi - Bogs at full throttle

I ended up putting some electrical tape over half of the air filter intake. That temporarily solved the problem. I'm going to order a bigger jet and see if that helps. This ped only has 250 miles on it.

What are some other things you guys would recommend to make it go faster? Biturbo?

Re: 1977 Puch Maxi - Bogs at full throttle

I'll also tighten up the drive chain.

Re: 1977 Puch Maxi - Bogs at full throttle

Ok Rob, Take the Tape off the intake. This could cause serious problems. The solution Is simple. Assuming that everything is stock, then we can solve the problem. Bogging out as they say is the result of a bad fuel to air mixture. If you say that covering the intake makes it run better, then it is getting too much air for the CC's. Youre bike was made to work right. It has the right size jet for the carb, and it has the right size intake, and it has the right size exhaust. So how is it getting too much air? the air flow must be restricted. The size of the intake going into the engine must match what is coming out. You know the intake is not clogged. So if it is running Good when you are clogging the intake, you are essentially Matching the Output. So you can assume that you dont have enough flow out youre exhaust. This is a common Puch Problem, and the manual even details cleaning it once in a while. You can remove the screw from the end, and pull the baffle out. this is a little tube with two holes in it. Then you can pull the whole exhaust chamber off. Fill it with carb cleaner, shake it up, dump it out, and do it again. This should fix youre problem.

By covering half the intake, you essentially cut youre engine power in half. Knowing that, you now know how to make youre engine more powerfull. the only difference in the Puch engine sizes, between 1.5 and 2 hp was the airflow. You get a bigger intake, ie 15mm, you get more air going in. You also need a bigger jet, because you need more gas to go in wtih the air, and then you need a baffle with a 15mm hole for the exhaust. Get a bigger Carb.

Oh, and better yet, Take that hole baffle tube thing out of the exhaust. than you have no restrictions, and can get a vaccuum going. You have to rig up some sort of way to keep the muffler from falling off. You could also just drill a whole bunch of holes in the tube as well. let me know if that helps.

Re: 1977 Puch Maxi - Bogs at full throttle

are you running this bike with the airbox off?

Re: 1977 Puch Maxi - Bogs at full throttle

No. I have the air box on. I will try messing with the exhaust this upcoming weekend. Thanks for all your help triumph

Re: 1977 Puch Maxi - Bogs at full throttle

adjust the needle inside the carb. take off the top and install the clip in the second from the top notch. This will correct your rich mixture.

tom

Re: 1977 Puch Maxi - Bogs at full throttle

i bet you still have two pins in exhust pipe. take them out. will go faster.

Re: 1977 Puch Maxi - Bogs at full throttle

could be as simple as your float bowl gasket not sealing up tight,it` happened to me more than once

Re: 1977 Puch Maxi - Bogs at full throttle

I agree, Gasket and Needle will help. I think the changing of the needle position might fix the bogging, but youll still louse the power. The carb gasket is a good point. Does youre Carb leak when its just sitting there?

Re: 1977 Puch Maxi - Bogs at full throttle

GET THE RIGHT JET AND BEFORE INSTALLING THE NEW JET CLEAN THE WHOLE CARB OUT CAUSE YOU RAN IT WITH THE AIR FILTER OFF

Re: 1977 Puch Maxi - Bogs at full throttle

what part of the muffler do you remove? i'd like to try that, but on a stock bike if you remove the baffle youre going to have to jet according to that too, right?

Re: 1977 Puch Maxi - Bogs at full throttle

i have been reading this thread because my puch has been having a similar issue.

it was working just great up until a couple weeks ago. on a drive across town it started slowing down its max speed (it usually goes at least 30 on a long straight flat road but this time it could only get up to 25) then shortly after that the engine stopped altogether.

i can start it and idle it just fine (except it idles fast now), but when i turn the throttle to rev the engine, the engine stops. i am quite new at engine troubleshooting. this puch was going to be my learning tool. it has had a slow gas leak since i bought it (about a month and a half ago) and i tried to look for where it was coming from. i may have changed the flow regulator screw in the process, but i have readjusted that screw since then to try to fix the problem with no success at all.

i did notice that the carb is leaking a little bit when just sitting there.

as far as i can tell all the engine parts are stock. so it makes sense to me that i shouldn't have to replace a part unless it's broken. all the stock pieces if working properly should keep the bike running as well as when i first bought it (presumably as well as when it was first made).

to me, my problem sounds very similar to rob's. should i be looking at the carb and the exhaust as possible sources of the issue?

any help is greatly appreciated

Re: 1977 Puch Maxi - Bogs at full throttle

I dont think you will. You might get a little increased airflow, but mostly, it dosnt add more air(Charge), but increases the speed at which the air can travel through. There is no resistance in the exhaust. more air traveling through means more suction, which will pull more gas through the jet anyways. i dont know. You should try, and see if it works better with a bigger jet.

A note about what I said earlier.

Drilling holes in the baffle allows more air to get through, but it still makes the air have to change directions to get out. It is going full speed straight, and then has to turn to get through the holes. This still slowes it down.

Let me try to explain how I did this once that worked great:

I took two allen wrenches, L shaped. about 4mm ish.

I welded the short ends together tip to tip

This made a large U shape.

However, i welded them at a slight angle so that the ends of the U came in slightly, and the bottom made a bit of a point. It was a diamond shape at this point. but the long end of the diamond was still opened.

I then took a washer that fit just over the bolt for the exhaust, which holds the muffler on.

I welded it to the open end of the Diamond, so that each tip conected to the oposite side of the washer.

Then, I put the diamond into the muffler so that the washer side is towards the back.. The slight point that was made with the little ends of the L, goes into the hole, right up against the bolt which comes through it. The Washer side goes over the Bolt. The nut goes behiend the washer. You can now tighten the nut, and it holds the muffler in place. It also does not restrict the air flow very much(depending on the size of allen wrenches. You want to use thin ones so that it dosnt block the hole too much. This also allows the air to go freeley around it, and out without having to change direction.

This is fun to do because if you dont like it, or dont want it any more, you can just put it back the way it was, and no harm done.

Did any of that make sence?

Re: 1977 Puch Maxi - Bogs at full throttle

So there is a float in youre carb. When it is floating, the gas stops coming in. if it is not floating, the gas keep coming, and floods up into the carb, and too much gas gets in, and the mixture is too rich, and you wont run. On a maxi, if your Carb gasket (the big one) is leaking, it will cause the float to not float all the way up, and it will flood the carb. A leaking gasket will also cause a loss of vaccuum in the float bowl, and too much gas will be sucked up into the carb.

You are right about replacing stock parts, however, some stock parts go bad. the Original Maxi had a plastic, hollow float. This plasic gets old, and breaks down, and leaks. this causes the float to no longer float. You can get a new one which is made of Foam for prety cheap. they still make them for this Carb. Someone else will know where to get them, start a thread to find the best place. The foam will always float, and never get gaslogged.

You will notice a small black button on the side of your carb. this when pushed in, will push down your float, so the gas can pour in. With the petcock open, and gas flowing, when you press, and hold this button down, does gas come pouring out the carb? Does it leak any more than usuall, or does it make no difference? Gas should come out of the base of the button actually.

If gas pours out when you hold the button down, that means that youre float is working, and preventing gas from entering the carb when it is full, and floating. If it makes no difference, and just leaks anyways, you proboly have a float problem. Replace the float. I know you can get a whole Carb rebuild kit on ebay for around $40.

Re: 1977 Puch Maxi - Bogs at full throttle

hey thanks for all that.

the regular leak in the carb is coming from around the top of the float bowl. i think there is supposed to be some rubber piece that should keep that from happening. maybe that has gone bad.

i just watched a video on taking apart a puch carb (and putting back together). it was very helpful. i haven't taken it apart myself yet, but i plan to soon.

oh, and yes when i push down the black button gas comes pouring out of the bottom of the button. the regular leak is much slower but it still leaves a small puddle under my bike if i leave it for long.

then again, maybe i just needed to turn off the fuel valve. i just found out that is what that little knob turny thing was for on the side of my moped ;). the leaking hasn't been as bad for the few hours since then. we'll see if it's a cure.

really

themaniel

Carburator re-build kit...

Ben Van Zoest /

SportsBay sell a re-build kit for Bing 12 to 15

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Re: 1977 Puch Maxi - Bogs at full throttle

hey themaniel

what video did you watch for taking apart a Puch carb? Is it online? thanks

shane

Re: 1977 Puch Maxi - Bogs at full throttle

yeah, it was very helpful to me. i actually found it on here (mopedarmy) somewhere.

here is the link to the series.

http://hobbies.expertvillage.com/interviews/moped-repair.htm

most of the videos are quite short and very helpful and informative, escpecially for a newbie (hi, that's me). hope you find it as helpful as i did. :)

maniel

New price is 50 Re: Carburator re-build kit...

fallout Survivor /

New price for sportsbay is 50 plus shipping for that rebuild kit.

Re: New price is 50 Re: Carburator re-build kit...

Um... this discussion is from 2007....

Re: 1977 Puch Maxi - Bogs at full throttle

Bang on the money! I've been pulling my hair out with this issue. Open the throttle and it just goes slower. I put some electrical tape over half the air filter hole (don't have the snorkel/tube) as suggested and success! Runs lovely now. Brilliant idea!

Looking back on it, this all started when I bought a new air filter. I'm assuming it changed the mixture some how.

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