pa50 carb questions

Jason Luther /

i cant get my hobbit to quite 4-stroking at full throttle unless i pull the airfilter out about 1/2 inch. so what does the air mixture screw do? is it only for low speed adjustment? and how do you remove the emmulsion tube in the carb. im just dying to remove the carb again!

Re: pa50 carb questions

That air screw is just an idle mixture screw. After the bike is warmed up this screw and the idle-speed screw are adjusted for a nice smooth slow idle.

The emmulsion tube is up above the main jet. It is only lightly press-fit into it's hole. It is secured in place by the main jet.

Remove the main jet.

See the little brass thing sticking up in the carb venturi? Stick a pencil or something into the carb's venturi and push down on it.. it's the top end of the emmulsion tube. This starts it on the way out.

Sometimes you can then pound the carb body into the palm of your hand and the tube will drop out. Don't pound it on anything hard.

If it doesn't fall out, try high-psi compressed air into the little brass tubes sticking out of the air (intake) horn end of the carb.. One of them (i forget which) is connected to the emmuslion tube cavity. The tube should blow out.

The tube could be stuck in there if there's a lot of junk or corrosion built up around the tube. A long soak in a cleaner might help dissolve that and make removal easier.

Re: pa50 carb questions

As far as the air filter question, it seems there's not enough air getting in unless you crack open the filter. Something's restricting air intake.

Examine the air box and the 3-holed rubber air-intake tube. Some critters could have built a nest in there. Use mirrors, poke around with a piece or wire or whatever.. remove the carb (ouch) as a last resort to examining the air box.

Clean the air filter element in soap and water and dry it out. The manual says to lightly coat the element with gear oil but, imo, it's not worth it. An oily filter element really restricts air intake.

but the oil coating does trap small particles .. it's up to you if you wanna dick with it or not.

Re: pa50 carb questions

Jason Luther /

i have done all of that with the airbox, and there was some crud and it helped a little, but im guessing the emmultion tube is the culprit. now that i know it comes out, ill clean it better. thanks

Re: pa50 carb questions

I am starting to think that Honda engineered it that way.

There are a lot of threads about Hondas 4 stroking at top speed. Mine will run right up to 30mph and then ffffaaaarrrrtttt

until it slows down to about 27 and then clean out again.

This tells me the following:

Air filter is overly restrictive

Muffler is overly restrictive

Main jet is too large

I am thinking about getting a #60 jet from a PA50I and drill it out to just smaller than the stock #78.

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