Carb tuning - too lean! Someone help

[theCATman]

They seem to run lean on the low end when cold, but after watching videos and reading about how to tune and jet cv carbs on motorcycles, I learned that the engine should run like that when cold and properly jetted...at least says some people on the motorbike forums. I don't know about a lean on top end. It would take me an hour or more to pull the plugs on mine!

Mine still had a functioning hood in '06. Otherwise I don't think I'd have ever thought of cleaning the carbs or checking plugs

 

[theCATman]

Back on topic.... OP, you get this issue resolved?

Anyone who says no re-jetting/tuning is needed after a major intake or exhaust flow modification doesn't know chit about engines.

 

[Metallicat]

These headers offer just a 5% hp gain at most, or 6 hp if you will. Well, at least the Excel does. When dynotech had this on their dyno they showed a reduction in low end torque, and an increase on the high end. I called Jim from Dynotech before purchasing my header and he said that there was no reason to rejet. It only makes more power over the stock exhaust after 7500 rpm, below that it makes less. It is just a very mild increase, maybe 3hp or 4 at the track. I assume the hauck is not much different.

 

[Yamaha4life973]

Put 150 main jets in it and plugs look awesome I had 5 miles before checking plugs first time have 800 miles on sled since thread and wow so much different of a sled she runs at 8700 and runs like a raped ape biggest difference is low to mid .

 

[Metallicat]

Did you make any other changes to the carbs besides the main jet changes?

 

[Yamaha4life973]

(I got my 06 Yamaha vector and purchased the hauck header and race pipes. Hauck sent me washers to put underneath needle and changed pilot jets to 48. Also they told me to set mixture screws to 2 turns. Also put upgraded springs in carb.) I did notice at wot going across a lake at 40 degrees it did get a little girgly after holding.it for a while but it cleared up after I let off a bit

 

[Metallicat]

Thanks, I'll try the 48 pilot jets. I tried the 50 pilots a couple of years ago and I could not set the idle with them. I'll also give the mains a try. I have my fuel screws all set to 2 turns out already. I shouldn't have to rejet at all with what I have, just the Excell header. They don't even recommend jetting changes...but what the heck...something to try anyway.