jetting

[Guest]

GS 1000 with 29mm smoothbores individual k&N pods and a Kerker 4 into 1. Installed main jets are 137.5 in 1 & 4 carbs and 135 in 2 & 3. Plugs 1 & 4 are black and sooty. Should I go to a 120 main jet in all carbs inorder to correct the fouling? The mixture is so rich I never have to use the choke to start it.

[TheCafeKid]

Just a guess but I think you should go to a 130 on all FOUR of them...

[tkent02]

Why not do a series of plug chops and you will KNOW what size jets it needs.

[TheCafeKid]

Why not do a series of plug chops and you will KNOW what size jets it needs.

Even BETTER idea...

[Guest]

plug chop? running the bike at wot pulling in the clutch, kill the engine then look at the plugs?How can this tell me which jets to use?

[TheCafeKid]

Youre close. You need to run the bike at differnt points in the carb circuits. What it will tell you is WHERE you are rich or lean. I would suggest that you, based on my limited knowlege, are still WAY rich on your jet sizes. You may try the 130s, i would bet 120s are too small..

[Guest]

will running rich harm the motor or just waste fuel?

[Guest]

Running rich will not hurt the bike.
What are the stock jet sizes?

[Guest]

stock mains I believe are 95.

[Guest]

With the 4-1 you don't need to run the different size main jets.
If the stock size is 95 120 sounds like a good start.
Is there a baffle in the pipe?

[Guest]

yes pipe has a steel wool wrapped baffle

[tkent02]

plug chop? running the bike at wot pulling in the clutch, kill the engine then look at the plugs?How can this tell me which jets to use?

Apparently it can't.

[Guest]

Apparently it can't.

sarcasm will get you everywhere!

Reading plugs has everything to do with jetting.

http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html

[67fire]

Well guys, hopefully I can help as I currently have a set of the same carbs on my Frankencycle! 1085 Wisco pistons, .394/.394 Andrews cams, Yoshi headers into 3" into 2.5" glass-pack.
They had 115 main jets in them out of the box. I dropped to 112.5 mains and it still did not need a choke at all. I currently have 110 main jets in it and it runs MUCH better at half to full
throttle! I still have a slight bog in the needle jets, so I am going to drop them 1 notch when my O-rings show up in the mail.

Hope, that this gives you a better idea of what you need to do...

Eric

[Guest]

Well guys, hopefully I can help as I currently have a set of the same carbs on my Frankencycle! 1085 Wisco pistons, .394/.394 Andrews cams, Yoshi headers into 3" into 2.5" glass-pack.
They had 115 main jets in them out of the box. I dropped to 112.5 mains and it still did not need a choke at all. I currently have 110 main jets in it and it runs MUCH better at half to full
throttle! I still have a slight bog in the needle jets, so I am going to drop them 1 notch when my O-rings show up in the mail.

Hope, that this gives you a better idea of what you need to do...

Eric

Did you raise compression to drop jet size?