I Am new to the moped world just picked up a running puch. There is no power at slow speed if there is any incline at all? It just Boggs down to almost a stop. Once I get rolling 15mpr there is definitely more power. Was wondering what I should look for. To get power at lower speeds. Thank you for any ideas
Low power puch maxi 1976
Re: Low power puch maxi 1976
Try starting off with a tune up. Plug, plug wire and boot, points, fuel filter and capacitor. maybe a new air filter.
Re: Low power puch maxi 1976
It's a moped. They are slow.
Re: Low power puch maxi 1976
You should read in the Wiki, you will find great info and a factory repair manual in PDF format.
Re: Low power puch maxi 1976
Slow mopeds can be ones with leaky seals and gaskets.
They suck in too much air, which makes the fuel/air mix lean.
That robs power and increases heat. So much that it can cause the piston to expand hard against the bore. It will wipe out lubrication and exponentially increase heat due to friction. The piston will melt and get stuck.
Seizing a piston is a bad way to start your moped adventure. Not trying to scare you, just want to make it a first point of caution before to go blasting around on your new machine.
You might have no leaks whatsoever. Could be slow for a dozen other reasons. But, make sure you learn how to check that and rule it out.
Re: Low power puch maxi 1976
How do I test for this leak? Compression test?
Re: Low power puch maxi 1976
Re: Low power puch maxi 1976
Easiest way to check for a leak is to spray a little brake cleaner onto the junctions of the engine while it’s warmed up and running.
Just tiny squirts all around the head/cylinder junction. Cylinder/case junction. Intake manifold base and where it clamps on the carb. Exhaust header flange.
If you make sure you don’t overspray directly toward the mouth of the carburetor while you spray any of the above mentioned spots and the engine rpm changes, that means it’s sucking in the flammable “fuel” (brake cleaner) and changing the combustion mixture. So, there’s a leak there.
Sometimes you can hear or feel a leak. Maybe even see a spot where oil is dripping or spattering from it.
There are crank seals that can go bad. One is on the clutch side and it might be hard to know if it’s bad. There were a couple recent posts where trans oil was coming out of vent holes on the upper rear of the engine. I suppose that could be how you’d see that seal leaking.
The other crank seal is behind the flywheel. If it’s clean and dry, it’s probably not leaking. I’ve never shot flammable stuff onto my ignition. Maybe someone else can chime in there.
That’s a lot of words, but only a minute of actual work.
Re: Low power puch maxi 1976
Thank you for all the help. I will check this out and let you know!!
Re: Low power puch maxi 1976
Most common and easiest to fix is improper air/fuel mix. What color is the spark plug?
If whiteish then clean the carb, clear the jet, make sure the air cleaner is on. If all these check out THEN look for air leaks. Do the spray test. If OK then think seals. Clutch side seal almost always smokes heavily when bad. Ignition side seal doesn't but is way easier to access.
If blackish, check the air filter screen in the airbox (the airbox pries in half) to see if clogged or rusty.
Ignition can also cause sluggish pick up. Read up on setting and cleaning the points and timing.
Re: Low power puch maxi 1976
I did find an air leak here it was a metal to metal connection. Fixed and it runs Much better:))
Though this bike has much less power than my 1979 motobecane ... I can only barely make it up a hill need to pedal. I have a main jet of 64 on this carburetor.
If I play with the throttle I can get more or less power.. didn’t do the points yet ..
Any thoughts?
Thank you for any help
Re: Low power puch maxi 1976
If you didn’t do the points yet you got to service your magneto because timing comes before jetting,
Read this completely especially 2/3 of the way down
Re: Low power puch maxi 1976
Great thank you!
Re: Low power puch maxi 1976
Clean points timed correctly, frame mounted condenser, cleaned cylinder ports, piston ring grooves, head, and cleaned exhaust all with new gaskets installed should make it a good runner.
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