Brand new to CV carbs, please help

[Guest]

So I have an 81 GS650G that I am having a heck of a time getting to run properly. The issue is I cannot seem to tune out these carbs for the life of me. I am having bogging issues like crazy. I have cleaned and adjusted the carbs a number of times but can only seem to push the bogging to different areas of the rpm range. Started at 5-6k but was popping, turned the adjustment screws out and now it is 4-5k. Also when I am adjusting the air/fuel screws I can turn cylinder 3 all the way in and it does not make the bike sputter at all like it should (#3 has low compression as well if that helps). Also my bike always seems to smell overly gassy, dunno. I am baffled. Thank you for the help.

[azr]

What threads and tutorials have you read so far on this site or Cliffs site?

[dackcommabig]

I have looked into disassembly, cleaning, rejeting, and adjusting these Mikuni carbs (and have done these things). I just cannot get that sweet spot. Sometimes it doesn't act up as much as other times, that is what has me stumped. I can't tell if it is something with fuel delivery (new lines and filter) or vacuum on that system or ignition? It seems like it just has a dead spot no matter how I tune it.

[tom203]

#3 low compression... How low?

The carb passages need to be thoroughly cleaned or mixture won't get thru them in right amount- compensating with idle stop screw and odd mixture screw settings will cause problems as bike transitions to higher revs/loads.
Did you bench sync the carbs? All throttle plates must be even- they will appear just about fully closed sitting on idle stop screw.

gassy smell .... Check petcock operation to rule it out as a problem, as it might be dumping fuel down the vacuum line to #2 at times.

[Dragon Breath]

Have you checked valve clearances? If the engine can't breathe properly, it won't matter what fuel mixture you throw at it.

[JTGS850GL]

Have you read this?

Carb rebuild tutorial

[JamesWhut?]

Stock airbox and exhaust?

By "adjustment screws" I take you mean pilot/slow/air jets? Those effect idle and up thru the mid-range, but are pretty much a non-factor by 5k rpm. If you are sure you have the carbs clean and set right, I would look at needle position. You may try shimming the needles and see what that does.

[dackcommabig]

Holy cow, I should have joined this forum sooner! Thank you all so much for the input, I have some work to do. I will keep you posted. Gonna tear the carbs down again and start there.

[dackcommabig]

I don't remember the number but it was signification lower and bleed off quickly.