Two part question. I've got a 2000 Buell M2 Cyclone. It's spending a lot of time in the corner of the garage gathering dust while my Road King gets all the play time. Two years ago, the Buell wouldn't run. I took apart the Keihin Carburetor and found the low speed jet completely clogged. I ordered a #45 jet and that solved the problem. I took the Buell out this week, same problem. I've got the Keihin carburetor apart again, cleaned in Berryman, and the low speed jet is plugged.

Using a fine wire from a wire brush, I've got the orifice open.

So my questions:

What is the proper orifice opening? Is "open" enough, or should I be able to run a certain diameter wire through the jet?
With a stagnant fuel system (lack of operation), what is clogging up the jet?

 

You should be able to see right through the jet. Buy a new one if you are unsure- theyre pretty cheap.
when the gas evaporates out of the carb and float bowl- it can leave a "varnish" on surfaces that can plug up small orfices (like a jet hole). You can get some super small drill bits and run one through it- just dont remove any brass. (A new jet would be cheaper than the drill bits). Put some Stabil or other stabilizer in the fuel to help with the varnish. Better yet- drain the carb when your not using the Buell.
Im jealous of your cyclone... i wish i had one.

i just reread your post- it does seem to be happening alot more than it should. Do you always get your gas at the same place? Could be dirty gas. OR- it could be something is degrading along the fuel system (o-ring/fuel line/tank coating) and its sending crap into your gas. Odd its only the slow jet though.

 

There's probably crap elsewhere in the carb and that is getting worked loose by the cleaner and getting stuck in the jet. Use compressed air/aerosol carb cleaner/pipe cleaners to clean EVERY orifice.

 

"i just reread your post- it does seem to be happening alot more than it should. Do you always get your gas at the same place? Could be dirty gas. OR- it could be something is degrading along the fuel system (o-ring/fuel line/tank coating) and its sending crap into your gas. Odd its only the slow jet though."


It's only happened twice. And the blockage in the slow jet is hard like tartar. But unfortunately the Buell gets a lot of sit time on a battery tender. -insert excuse here- why I don't get around to riding it more. I'm going to put it back together tomorrow and ride it around. I'm assuming the remaining varnish will wear away with some run time and a tank full of fresh gas.

Thanks for the responses so far

 

Whenever you pull a clogged low speed jet, it might be close to getting a stuck float valve, or not seating all the way. Not much more work to drop the float valve and clean it and the seat real good. Whatever gets in a jet is probably getting in everything. If that float valve stops seating all the way, the carb will leak gas, if it sticks in the closed position, the bike won't even start.

 

My Buell is back together. Started right up. The enricher/choke **** housing broke as I was tightening it back into its bracket. But 20 year old plastic will fail and for less than $15, I have another one coming. I put 15 miles on it today in <40 degree weather. I forgot how fast it was.

I'm pretty sure it was varnish that plugged the slow jet, but I saw aftermarket fuel filters when I was looking for choke parts. Does anyone have any feedback about slipping a fuel filter on your fuel line?

 

You already have a fuel filter, it is on the petcock inside the tank, you don't need another.

Automotive filters need pressure to work and won't flow with just gravity. Only filter would be one made for motorcycles or lawn equipment, but the one in the tank will still clog first anyway.

$0.02

 

You had said it was plugged with a black tar. Ethanol fuel will deteriorate old fuel lines.. is the fuel line from the petcock to the bowl soft. My cross over line from tank to tank was so bad that it wouldn't transfer fuel from right tank to left tank.. Seeing your is a 2000, you might be experiencing the same thing..Ethanol eats that **** up..

 

I think it's time for a new fuel line.....

 

Have you actually burned thru all the old fuel in the tank, or at least drained it out and filled with fresh?

Or are you one of those "10 miles per year" type 2nd bike owners.