So my bike would start to putter after it was in 4th gear and get past about 5k rpm. It only did it in 4th 5th and 6th gear so I took my carbs apart and cleaned them and they really weren't dirty which got me thinking. So I looked up some info on the jets and it seems that 1 and 4 are a different size then 2 and 3 but since my bike has been modified some by the previous owner, I dont know whats right anymore. My jets read 1 and 3 are at 134 and 2 and 4 are at 136. Should it be 1 and 4 at 134 and 2 and 3 at 136?

Also, I bought a carb kit that comes with 140's and 145's. Im assuming they are bigger then what I have?

I could really use some help here boys.

Thanks

 

my 95 manual says 1 & 4 are 135s and 2 & 3 are 138s. What year is your bike and what kind of mods?

 

I believe the engine has been bored over but im not too sure.

Its a 97 600

 

bigger jets always go on the inner two cylinders. do you have the stock exhaust on it or aftermarket? stock air filter or k&n?

 

Its an aftermarket exhaust and I have the K&N Air filter. I was also wondering about the D screw. What should it be turned out at and should I even mess with it. The bike has to start with the choke on and then after about 30 seconds I can close it and it runs fine

 

Starting with choke is just the nature of the beast. I've got 142s on my carbs. Carbs are the only thing I have not repaired myself on the f3. I know most of the time you use two different sizes but I could have sworn my mechanic said I had 142s across the board. Maybe not. I've got a full muzzy exhaust and the k&n air filter. All the air hoses and air solenoid are gone. I just have the airbox and the two hoses that run along the side of the box into the carbs. I swear she is singing the tune.

 

unless you know what youre doing, dont mess with the D (pilot) screw, you'll drive yourself nuts trying to get it right.
but with the exhaust the filter, you should be running larger jets. if one hasnt already been installed, get dynojet or factory pro jet kit, if you have adjustable needs then youre good to go. After that, id start with 136 and 138 main jets with the needle clip in the middle position, then get it on a dyno with an exhaust sniffer, shouldnt cost you more than $50, and that will tell you where you need to go in tuning.

 

I put 140's and 145's on today. I also undid the D screw and took everything apart and cleaned it out. I counted the turns and all that. 1 and 2 were at 2.5 and 3 and 4 were at 2.75. When I pulled 4 out, it was black unlike all the other ones. Does that mean anything? And should it be at those numbers cause I read it should be between 1.75 and 2.5 in the manual.

 

1.75-2.5 is from the factory with stock exhaust/filter. Just put them back to where they were when you took them out. but the difference in your jet sizes is too much, get a jet kit(they come with 10 or so different jet sizes, 130's to 144's i think is what mine came with) or if you already have an adjustable needle then find an assorment of jet sizes.
anyway, just get it to a point where you think its running pretty good, then get to a dyno, thats the best way to know for sure if youre running too rich or lean, and with 140's you might be running too rich, ive got a full exhaust and im running 138's and 136's, and im still slightly on the rich side.

 

Okay so I wont put the 140's or 145's in ill just keep it stock with 138's and 136's. Now my bike wasnt running very well when it got into high rpms in 4th 5th and 6th gear. it would start to bog out. Would the needles have anything to do with it?