Puch2spd./Low Power

Michael Nesson /

Finally have my 1980 Puch Maxi running. It starts up great now and runs fine. It has low power comparerd to my other ped. Cleaned the points and they break just right. Changed the trans fluid with 9.5 ozs of fluid. Seems to buck a little at the top rate of speed 22-24mph. When you twist the throttle to full, it looses more power and wants to stall. Any ideas or help! Thanks!

Re: Puch2spd./Low Power

Restrict airflow into the airbox by removing the tube going into the frame and covering about 2/3 the remaining hole with duct tape. Very common problem with Puchs is that there is supposed to be a restrictor plug on the end of the tube going into the frame. Don't ask me why it's always missing, but it is. Mess around with the duct tape, do some plug chops, and you'll be up to 30 I predict.

Re: Puch2spd./Low Power

Tyler Jacobson /

is it a 1.5hp ? they only do like 25 stock i tinkered with my 2speed 1.5hp puch and an old biturbo exaust and it does 29-31ish

Re: Puch2spd./Low Power

Michael Nesson /

I'll try the duct tape suggestion! It seems to loose power going uphill....I'm surprised to have such little power; my friend's 1978 maxi (1spd) is very fast and powerful. I thought a 2 spd would be the same if not more power. My '80 looks like your '78. What could the small buck be? Any ideas or suggestions

Re: Puch2spd./Low Power

Michael Nesson /

It's a 1.5hp, 2spd. My friend has a 1 spd(maxi) '78 that is very powerful.

Re: Puch2spd./Low Power

Michael Nesson /

How do I do plug chops?

Re: Puch2spd./Low Power

Mitch Buchannon /

Read Fred's guide to moped repair. There's a section in there on how to do plug chops. They are very helpful.

http://www.mopedarmy.com/resources/articles/10/

Re: Puch2spd./Low Power

Gregory Mcintire /

Why would you want to restrict air going into the input side of the carburetor? That is the same thing as having the choke part way on. If it needs restriction in order to run rich enough, then it simply needs a leaner (smaller) jet and NO restriction.

A very common reason that small 2-stroke engines get low power is that their exhaust system gets plugged with carbon. This happens slowly over time and therefore is often overlooked by the rider. If your Puch has the stock exhaust system, clean it.

Remove the entire exhaust pipe from the moped. Take off the nut in the rear end and remove the inner muffler/baffle and clean out all its holes (not just the short 4 inch pipe in the end, but also the entire footlong aluminum canister inside). If it is stuck in the chrome exhaust badly enough you may have to drive it out. To do this wiggle loose the head pipe and pull it (and its associated rod) out of the main part of the exhaust. Now you can put a 5/8 inch diameter or so wooden stick (dowel rod) into the front end of the muffler and with a hammer, tap on the stick to drive the aluminum muffler/baffle out the rear end. Clean out all the visible holes then reassemble. Also be sure to scrape off any carbon that may be in the actual exhaust port of the cylinder while you have the exhaust off of the bike.

This has to be done from time to time, depending on the oil you use, the ratio you mix it at, and how you ride. A good synthentic 2-stroke oil will basically alleviate the carbon buildup problem. Well worth the extra bucks for this reason alone in my opinion.

Re: Puch2spd./Low Power

Gregory Mcintire /

" If it needs restriction in order to run rich enough, then it simply needs a leaner (smaller) jet and NO restriction."

CORRECTION... It is still too early in the morning ;-)

I should have said if it needs restriction in the input side of the carb then it simply needs a LARGER jet (to compensate for the choking affect of the restriction) and then no restriction.

You want to give the carb all the air that it can possibly use, then jet it to accordingly. You don't want to regulate your fuel mixture by choking the input side of the carburetor for two reasons. One, it will give you less fuel/air mixture (read less available power) and two, it is ver irregular, i.e. mostly affecting the wide open throttle and not at all affecting the low throttle.

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