Carbs balanced, now running pants.

[gixeriain]

Ive just got round to balancing the carbs on my stock b12 as it was spluttering when pulling away. They were a tad out. Got them bang on now. But when the motor is warmed up, on tick over its very lumpy. Kinda firing on 3. Motor is standard and only done 39,000 miles and so is airbox. Any ideas ?

[canamant]

did you put the plugs back on the vacuum point ?

 

[gixeriain]

Sure did.

[canamant]

well it's not that then :-)

 

[Fazz711]

Trapped fuel line maybe? 

[nlovien]

does it run better if you raise the idle ? - another one is you've balanced using the throttle slide adjusters - now go to the idle screws - maybe just a 1/4 turn on these could bring it back in " typical idle screw adjustment = turn one way listen for rpm rise or drop and splutter - turn the other way listen for same - where you get the highest rpm rise, set them at this position, then adjust idle via the main throttle adjuster"

[Oilyspanner]

It's got std carbs I think: so If the carbs are balanced, the throttle butterflies are adjusted - the slides work on vacuum only and aren't mechanically operated like Rs / FCR/TMR carbs. The air filter and plugs need to be in good working order before balancing, is all okay ? Checking the pilot mixture screws is a good idea once the filter/plugs/ht leads and plug caps are checked.

If it was spluttering off idle before and it's even worse when balanced, then there could be another problem causing richness (at least it sounds like it) - such as  worn needle jets, they can cause rough running even at low revs. Check all the normal serviceable stuff first though.

[gixeriain]

Cheers folks. Got a day off on tuesday. Gonna put new plugs in. Need it running good. Going away on it on thursday for ten days. Plugs do look like its running rich too. 

[gixeriain]

New plugs in and carb repair kits in the post. Borrowed a mates xjr 1300 to go away on. Interesting torque on these buggers.