STOCK PUCH SPEED
According to the manual a 1.5 hp Puch Maxi top speed is 25 mph and a 2.0 hp Maxi 30 mph.
If no one has changed anything, you should be able to bring it back to the design speed without any drastic measures or expense.
Try to get it running to its original design before “souping it up”.
Check and implement the following before doing anything rash.
A. The easy stuff.
1. Get a manual. You can find them on eBay for about $20.
2. Calibrate your speedometer. Find a straight flat safe section of roadway and mark off a reasonable length. Say a tenth or twentieth of a mile. Get a stopwatch and you can figure out the rest. If your speedometer is unreliable (does not repeat), then you will have to use this method every time you make an improvement try.
1. Make sure your gas to oil mixture is 50:1.
2. Check tire pressure. 26 psi front and 32 psi rear.
3. Check your wheels to see that they spin freely.
4. Check and adjust your chain tension. Vertical play should be about 3/8 inch.
5. Remove the air box and look in the carburetor while operating the throttle and choke. Both should fully open.
6. Make a trial speed check. If nothing has improved, go to B.
B. More difficult and requiring some mechanical ability.
1. Before starting on the carburetor, check your gas tank and fuel valve.
a. Before removing the carburetor, remove the fuel valve. Be careful with it. A new fuel valve is over $20. This is where a manual comes in handy with pictures of the parts.
b. If there are signs of rust, you will have to clean the fuel tank. One suggestion: tape a small hose to your vacuum cleaner and put it in the tank though the fill hole to vacuum out the loose rust. The rest is up to you.
2. Check and/or clean the critical parts of the carburetor. For a given airbox, carburetor, manifold, engine and exhaust system configuration, fuel to air mixture is probably the most critical factor affecting engine power (speed). A dirty carburetor (jet) or a bent float (fuel level to high or too low in the bowl) can significantly affect fuel to air mixture.
a. Remove the air box and the fuel line.
b. Remove the carburetor by unscrewing the two nuts holding the manifold (elbow) from the engine.
c. Remove (unscrew) the bowl. .
d. Remove the inlet connector (looks like a banjo) carefully. There is a little cylindrical screen (filter). Inspect and clean it.
e. Using a small metric socket, remove the main jet. Clean the jet with a copper wire (020” or less diameter. Do not use a drill or steel wire. Even be gentle with the copper wire.
f. Leave the cable connected and immerse the entire carburetor in cleaning fluid and leave overnight.
g. After blow drying the carbuertor, check the float by holding the carburetor upside. The float should be parallel to the bowl mating surface.
h. Put it all back together and make a trial run.
3. If you do not get the design speed, clean the head and top of the piston by simply removing the four bolts that hold the head to the cylinder and scrape off the carbon.
4. If you still do not get the speed, you can check the points. If the ped has low mileage and has been stored in a clean dry place, the points should be ok.
a. Remove the sparkplug.
b. Remove the magneto cover.
c. Rotate the flywheel counter clockwise. Clockwise for a two speed Puch.
d. When the points are fully open, the point gap should be between .014” and .018”.
e. Adjust only if you have to.
5. If you still don’t get the speed, get help!
C. Getting speed beyond the stock design reguires new equipment in this order:
1 New muffler: biturbo about $100 Mechanically very easy.
2 Larger carburetor and manifold. About $75. Also easy.
3 Different sprockets. About $30. Pickup and hill climbing is compromised.
4 Higher displacement. 60cc or 70 cc. About $200. Some risk here.