pa50II carb...

My bikes symptoms are very much like other hobbit owners. Bogging out at full throttle, cutting out every 10 min or so. Everyone says to clean the carb and I agree, but I have never done it and need some advice. I've found some articles on this site about it, I guess I just need somthing a little more in depth or somthing. I own the manual and all, but all of your guys' input helps me much more. So all yall pa50II gurus help a hobbit out.



Re: pa50II carb...

If you get stuck and need info on this particular carb, say so. It would take too long to write complete carb cleaning instructions. Here's a basic outline.

Everyone has their own way of cleaning carbs. Basically you find a clean area on a work table and take the carb apart and clean the individual parts. Hold the parts in small metal bowls or whatever. At least use one for clean parts and one for dirty. Some parts are tiny so you also want a clean, flat floor under you. You will drop a part on the floor.

Leave the choke and throttle butterflys alone since they are easy to clean where they are. Disassemble the rest of it.

PAy attention to where the little parts came from. Keep notes and draw pictures if you have to. It's helpful if you just stop and think about what the part does .

Like the air screw.. has a long point and a spring. Note that this spring is not as heavy as the spring on the idle speed screw. The point is shaped completely different. Notice these things while you disassemble it. You will become familiar with the carb.

In fact, it would be helpful if you partially disassemble a section and then put it back together before cleaning anything.

Take the float bowl, for instance. Note the orientation of the bowl itself. (It is possible to put this carb's bowl on backwards.) The float and the float needle fit together a certain way. Take notes. Practice reassembling that.

The main jet can be unscrewed. Use a screwdriver that perfectly fits the slot or file the tip of a screwdriver flat and straight so it fits. Don't be in a hurry.

Above this main jet is the emulsion tube. It is not screwed in but it is friction fit. It won't fall out when you remove the jet. Give it a push from inside the venturi. (it protrudes slightly into the venturi) The emuslion tube can be forced all the out with compressed air through the small tubes/holes in the airhorn.

(WHAT is a venturi.. what is the airhorn??? Don't even start this project before you know what the basic parts of a carb are called and how a carb basically functions.)

Soak parts in a solvent. A amall brass wire brush is helpful to loosen dirt. Use a good magnifier and one of those tiny flashlights to see into ports. Blow out passages with compressed air.

I do not recommend ever sticking a metal wire of any type into any jet. Brass is soft and easily scratched. Soak in solvents, use stiff plastic brushes and compressed air. Be gentle and be careful. A carb is a precision instrument. Treat it like it was a camera.

Re: pa50II carb...

thnx for the advice!


Re: pa50II carb...

Edward Edwards /

ljoew, did'nt you once say that this carb has an idle jet under that screw that doese'nt do anything? Would you please explain further. Thanks

Re: pa50II carb...

There is a flat head screw near the idle speed and idle air screws. Just to identify it, I said _the screw_ doesn't appear to do anything, as opposed to the air and speed screws. The jet under it certainly does something.

This screw appears to be nothing more than another access point for cleaning out the passages. Directly under this screw is the idle fuel jet. You can see the top of the jet.

This jet seems to have been installed through this screw hole. As far as i can tell, there is no way to get the jet back out... no way short of drilling out a plug and somehow pushing it out from underneath.

As far as cleaning the jet and the passage under it, a good long soak in carb cleaner, a brush with long stiff plastic bristles and lots of compressed air should do it.

The hole in the jet is tiny. Sticking a pin or anything metal through it is risky. And any crap you push into the passage beneath the jet will try to come back through the jet and may clog it again.

how it works..

Fuel from the bowl is drawn upwards and up through this jet. Here the fuel is premixed with air from the smaller tube in the air horn. This preliminary air/fuel mix then travels to the idle air screw where fine tuning of the idle air fuel mix takes place.

The idle fuel mix is sprayed into the bore at the throttle butterfly.. look in there and you see two tiny holes and a larger hole in a group. All three of these holes communicate with that idle air passage.

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