Carb gurus

[Kraptanaman]

Gsx1170 engine. Dynojetted carbs run great in top gear and 60-80 mph.  Low down spluttering.  Is it just needle height?

[Jaydee]

Could do with a bit more info to get close to pin pointing the problem.

Does is idle okay?

If yes, is there a flat spot? Where on the rev range?

The needle height position has more to with the transition from the slow circuit tapering off and main kicking in. 

The problem could anything from mixture screws too lean/rich. Float heights too high (slow circuit flooding/bogging down but able to handle the fuel metering at full chat). Blocked slow air/fuel jets, carbs out of balance or a combination of them.

All I can tell is what it's not. If it runs great at top end, it's (probably) not the mains.

Edited June 12, 2019 by Jaydee

[Sheep]

Try putting two marks,one on  your throttle grip and one opposite on the switchgear housing.Then turn the throttle (engine off) through 1/4..1/2..3/4 making extra marks at each point opposite the switchgear.Go for a ride and make a mental note how the bike reacts at given times in relation to the marks you made....This will help you determine where in the carbs you are experiencing most of your problems...

Obviously keep your eyes on the road as much as poss

[Reinhoud]

A/F gauge with O2 sensor

[Dezza]

Do the barbs have air correctors fitted? I ask as this is the classic symptom that was resolved by the fitting of a LeDAR induction kit, which included air correctors fitted by tapping a thread in the small recess in the back of each carb. I am assuming you are running the stock or other CV carbs.