Clogged pilot circuit? or something else?

[pullshocks]

My 83 has been running like crap.  Part of the problem was a no spark on the rear cylinder, but even with that fixed, and carbs synched, it runs poorly.  It starts and idles, but stumbles or dies when you roll on the throttle, even with the bike in neutral.  This is with the idle adjuster screwed in to maximum.  In other words you have to turn the idle up all the way to get it to idle at 1300.  The stumble is pretty severe.  By increasing the throttle very gently you can get the RPMs up but response is jumpy and uneven. 

YICS box is off and fittings plugged.  Float level and accelerator pump function were checked a few days ago.

I tried to adjust the mixture on the rear cyl.  The mixture screw had no effect.

I know fuel is getting to the rear carb (fuel comes out the drain) and the rear exhaust pipe is hot, so I know it is running, just poorly.

I applied the choke, which brought the RPM up to 3K or so.  Leaving the choke applied, I backed off the idle adjust screw binging the RPM down to 1300.  It idled much better, and the stumble was pretty much gone.  I did not test ride it but in neutral you could rev it up pretty smoothly, and it just plain sounded better.

I noticed that the above adjustment had changed the synch considerably

That is where I had to leave off for the day.  Would I be correct in concluding that the pilot circuit is clogged, causing it to be too lean at idle?  Other than yet another carb cleaning, is there anything I can do?

As I understand it the pilot circuit starts just above the pilot jet and exits into the intake stream via the tiny holes below the throttle.  The pilot jet is easy enough to clean and check, but the rest of the circuit is very difficult to clean...what tips and tricks do you guys have?

Thanks
Pullshocks/Mark

[kev10104]

It might be your throttle cable needs adjusting.

[Rikugun]

If you're certain the ignition woes have been ironed out, it sure sounds like the low speed circuit is suspect. An improvement by application of the enrichener fits the diagnosis too. Does the fuel filter seem like it has some junk in it?

As far as cleaning: ultrasonic in a carb soaking solution if you can - just soaking in a good carb solvent if you don't. Carb cleaner spray and compressed air is the old (barely) adequate method. When you spray/blow through the various circuits, visually check the same thing happens with both carbs.  ie you're blowing solution through the idle circuit and it exits into the venturi with some degree of force and volume but on the other carb it barely burbles out, something is amiss!

Don't forget to re-sync when you're done cleaning them as I suspect the're wrong now.

[pullshocks]

Well, that was exactly what was wrong.  Pilot jet was full of gremlin snot.  Everything else was clean.

Synched up and seems to be running pretty bleepin' well.  Road test tomorrow.

[munkyfistfight]

I can't wait to clean mine again. I have it running well enough to be road worthy, but I have similar symptoms. I'm having a hell of a time getting the pilots set, and it idles poorly. I took them to my godfather earlier this year (motorcycle mechanic) but I didn't get them back for almost 4 weeks and when I did get them back, they weren't assembled and I could barely tell if he'd cleaned them at all. I'm just going to do it myself next time. Congrats on getting yours straightened out!  :D

[pullshocks]

Finally did the test ride last night and it is running great.  No stumble, no dying at stop lights.  Hopefully if I use Sea Foam it will prevent the carbs from clogging up again.

[munkyfistfight]

I wanted to ask about using seafoam because I use it for everything else. Is it safe to use in our tanks? I thought I read somewhere that it isn't good for the petcock...but I could be wrong. I found a little black speck of something in my fuel filter yesterday. Now I'm glad I have it on there.

[Lucky]

seafoam/berrymans are fine to use unless you have a vynal (Kreem) tank liner. they will turn it to goo & you don't want to clean that out of your carbs/ petcock.

it's not unusual to have to reclean the carbs after the first cleaning because vibration from running the bike loosens more stuff...

[YellowJacket!]

I've been using seafoam for a while and it has been working really good for me AFAIK.  Just don't use too much as it will run like crap.  I also noticed that whenever I use some seafoam I get a bit of bluish white smoke....probably should use a bit less.

David