plug fouling

Patrick Mattison /

My pa50 will start and run for about 5min, then die out. The exhaust looks dirty. Will burning out the carbon (Fred's Guide) fix/significantly improve the problem you think?

Re: plug fouling

Sounds like it's running out of fuel or the gas cap vent is clogged (Creates a vacuum in the tank). Examine, clean and fix the entire fuel system. Tune everything up. If it gets up to near 30MPH the bike (ignition , compression and carburation) must be pretty much ok. If it's dying for no reason after a few minutes, suspect the fuel supply.

And if it gets to 30MPH, that muffler is probably clean too, but here's some stuff about that muffler:.

Remove the right side muffler heat shield .. Under it is a big bolt. Remove that bolt.

Directly inside that bolt hole is small baffle tube, about 1/2 inch inner diameter. All exhaust must pass through that tube.

Stick a scrwdriver or something in there and make sure it's cleaned out. The screwdriver must penetrate the muffler 5 inches or more to completely clean the tube.

Baking that muffler will probably destroy an otherwise nice muffler. Anyway, there's no reason to do it. I've cut an old one open and very little carbon accumulates anywhere except in that little tube.

Re: plug fouling

Patrick Mattison /

no, it bogs and the plug comes out black & wet (new plug)

Re: plug fouling

Patrick Mattison /

thanks for the diagram though.

Re: plug fouling

Either too much gasoline or too little air can cause a rich mixture that fouls the plug.

Too much gasoline can come from a leaking fuel inlet - float needle similar.

Too little air intake can be due to a clogged air intake box / filter, a partially closed choke, or similar..

Describe all the symptoms. Did the bike ever run better? What is top speed right now?

A restricted exhaust is another possibility. Aside from the muffler, check the exhaust port for carbon build-up.

Nine times out of ten the symptom points to carburation .. but more info about the current condition and history of that bike could provide some clues that might point to something else.

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