New year, same old carb issue. (idle rpm)

[gorbys]

I couldn't get all this to add up with the low compression. Like why would it be so bad if the piston rings where new,valves lapped.... so I checked timing and... bingo!

Cams where off. I don't know, maybe the crank moved when they where installed

I redid them and boy did it make all the difference! After some fettling with the carbs and idle i had it sitting at 1200 for minutes! Damn steady! I'm delighted! 

Will sync the carbs tomorrow, recheck ignition timing and compression. Take a test ride 

[TonyGee]

always pays to double check cam timing 

[gorbys]

Short video of it idling and a little rev. Probably still a bit fat

https://youtube.com/shorts/rJWhrDFmxP0?si=OPjBRL2MNHBxBtLJ

[ProducerBill]

On 4/23/2024 at 11:12 AM, PanzerWomble said:

As Tony says you will need to back the mixture/pilot screws out on all 4 carbs as they control idle circuit - the knob in the middle (57) just sets the throttles to idle. 

Turn pilot screws in GENTLY until they bottom. Turn all out 1/4 turn at a time (wait 15 seconds between each 1/4 turn adjustment to give engine time to adjust) until highest RPM idle is obtained. Normally do not turn the pilot screw out more than 2.5 turns. If you must turn it out more than 2.5 turns go up to the next larger pilot jet. I've not an ET manual to hand so check that as it should give the the factory setting .

Once you get to high idle you should be able to turn the one control screw ( 57)  in the middle of the bank to get the 800 revs.

 

Pilot screws are the ones in the turret at the front of the carb nearest the engine

Pilot jets sit below part 38 

 

 

What RPM should I be set at while making the idle screw adjustments?

[TonyGee]

58 minutes ago, ProducerBill said:

What RPM should I be set at while making the idle screw adjustments?

strange question ?  the idle screw controls the rev's at idle !!!!  

Edited June 28 by TonyGee

[Gixer1460]

I guess he means adjusting the mixture screws! 

Set idle to where you want it idling then adjust mix screws equally - this will affect idle rpm! It's a balancing act !

[Safra]

There is one issue plaguing the old Mikuni BS carbs because of age its the throttle shaft seals mine needs to be replaced, have a look for a almost oily sandy residue around the butterflies that looks like carbon buildup I have exactly the same symptoms as you've discribed "False Air" lean condition that isn't fuel related with pops and bangs off acceleration 

[Safra]

Just now, Safra said:

There is one Overlooked issue plaguing the old Mikuni BS carbs because of age its the throttle shaft seals mine needs to be replaced, have a look for a almost oily sandy residue around the butterflies that looks like carbon buildup I have exactly the same symptoms as you've discribed "False Air" lean condition that isn't fuel related with pops and bangs off acceleration 

 

[Reinhoud]

Didn't read any replies..

 

My GS1000 never idled very nice, not stable.

Check for vacuum leaks, check your carb synchronisation, probably also check the valve clearence, even old sparkplugs can be an issue.

With my GS I bought a color tune, I always thought they were stupid, but with this you can adjust the carburfuckingettors independently, and that can make quite a difference!

I noticed my pilot jets were too small, Frankenstein bike

[Seana]

Someone may have already said this but have you renewed the inlet rubber orings or is there a split in the rubbers somewhere as this defo sounds like an air leak between the carb and engine......

[Seana]

On 7/4/2024 at 11:17 AM, Reinhoud said:

carburfuckingettors..... here be the truth