I need some serious help!

yes it is me again, the guy from seattle that has the 78' PA50II. So i just ordered the malossi 70 cc kit. But before i put that on i want to get it up to top speed. it will get to about 22 and then it will bog down like it is flooding or something. I just cleaned the carb and used oven cleaner to clean the exhaust. It did not help. I dont know what could be the reason it wont go any faster. I am also having some serious idle problems.

Re: I need some serious help!

The first thing you need to do is ride it at 22 for a while .. then stop on the spot and pull the spark plug .. and report what you find.

When you cleaned the carb .. did you push out the emulsion tube above the main jet ?

Got to do that.

Did you remove the main jet and look through it ?

Did you blow the carb out with 80psi compressed air ?

Do you have an inline fuel filter ?

Have you dragged a piece of 400 grit W&D sandpaper throught the points ?

If you don't specifically answer each one of my questions .. I will not try to help you.

Re: I need some serious help!

pull your slide throttle out and check under the spring for your throttle cable, it may be split and bunched up... hanging it up at half or full throttle, flooding it. after replacing the cable, lubricate it with PB blaster (penetrating oil for breaking rusty bolts)

I need some serious help!

follow fred's advice, he really knows his japanese mopeds best of all.

also, some mopeds start performing better the more they are ridden around. so if you only recently got, you can probably assume that it hasn't been ridden much.

also check your jet size. i don't know anything about the pa50, but someone here might tell you if your jet is too small or too big. also note what size your carburetor is.

finally, your moped might have some restrictors on it that were meant to keep it at about 20-25mph. some states had laws that limited mopeds to that speed (some even as low as 15mph). it might come down to removing those restrictions (larger carb, larger manifold, larger jet, different belt, different clutch, etc).

post as much specific information about your moped as possible and i'm sure someone can tell you what's what.

Re: I need some serious help!

ANT .. that bike doesn't have a throtte slide.

... its a butterfly carb and the throttle cable is strictly external .. a simple clamp screw anchors it.

Re: I need some serious help!

jesse smith /

In response to Fred

I do have an in line fuel filter, i did push out the emulsion tube and unscrewed the main jet and both are as clean as a whistle, i did a plug chop and the plug was a light brown color, i have not cleaned the points and only used canned air to blow out the carb, but i have cleaned the carb about seven times in the last three months because i was sure that it was the problem as per your advice and i dont really think that is the problem

In response to miguel i have had the ped for a while and it was running at about 29mph and then all the sudden it started to top out at 22.

Re: I need some serious help!

OK .. then it sounds like you have been pretty thorough.

But next .. pull the s-paper through the points like the guide says.

.. and check ign. timing if you can.


.. have you tried running with the exhaust pipe removed ? (as a test)

.. have you looked into the cylinder exhaust port for carbon clogging ?

.. have you inspected the cylinder bore and piston for evidence of seizures and scuffing/scoring ??

(remove the cylinder .. while you are there check and see if the rings are free .. not gummy and sticky)

A PAII should go 28 like you said it used to .. it has to be one of the things I mentioned above.

Missed one, Fred.

Also a good idea to check the airbox/air filter, whichever a PA50 has, cause that being ratty or plugged up would hurt performance too.

Just a thought,


Re: Missed one, Fred.

I wonder Fred,Ree=(T), if he just doesn't have a bad spark plug? Those things can sure go sour in an instant seems like. don-ohio (:^)

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