GS 650, issue with carb 1

[Sarcvicious]

Trying to sync the carbs w a colortune. Originally carb 2 was giving us issues so we pulled the carbs, I realized the float needle was bad, I replaced it, adjusted the float tang, and everything was in spec clearance wise (22.4mm +/-1mm).

Put the carbs back on. Carb 2 is leaking gas now so clearly I over adjusted it and the float level needs to be lowered. Cool.

carb 1 is also giving us issues. The cm HG Is reading WAAAY higher than the other three on the colour tune. We can tighten the vacuum adjustment screw all the way, and carb 1 is still too high.

blipping the throttle causes 1 to jump up a lot faster than than 2/3 but it even jumps up faster than 4.

any idea what kind of adjustment I need to consider with carb 4? I’m assuming I need to pull the carbs off again, but I’m not sure what I should be looking at right now.

 

[Sarcvicious]

Oh and just an update- checked pilot jet passages. They’re clear. Rechecked float tang height and made adjustments to the one that was off.

I have the dyna jet main jets installed (155s). Is this something where I’m going to need to move the e clip? I’m not sure how the measurement on the carbtune relates to a carb being too rich or too lean.

 

[Nessism]

Did you actually change the float needle, or the entire float valve? In either case, what brand of parts did you use? In my experience, the needle should not be changed individually, only the entire float valve. And only Mikuni or Keyster brand float valves should be used.

Realize that float height is just an approximation to getting the fuel level correct. Said another way, the float height doesn't matter, as long as the fuel level is correct.

You need to vacuum sync the carbs. Set all the pilot jets to 2.5 turns open for starters. Color tune can be used later, if the bike doesn't run right. Carb tune, synchronizer, should be used straight away.

 

[Sarcvicious]

Sorry just got this. I changed the float valve. Broke the rules used after market parts. And found one of the new needles/valves already failed after a few months.

 

[unfocused]

I use the Motion Pro liquid sync tool.

Always remember - [NODE="2"]Forum[/NODE] is the primary carb for syncing. Everything is set to it.

Back in '19 I picked up my 77 GS750. Carb issues obviously. Found out that the slides weren't level and needed to removal to discover why. The actual issue was with the slide bracket causing the slide to stay suspended even with the idle screw backed off. [NODE="1"]Home[/NODE] carb was fine and it was uphill from there. It was ugly. Required a little grinding and everything was bench synced. This set of carbs still work well. I can supply pics showing what needed repaired.