would like some help 94 cbr f2 with K&N full D&D pipe . Cruising at 3500-5500 feels like it's starving for fuel and surging. With choke open a little it smoothes out. even after stage one jet kit. carbs are clean pilot's are claen. i'v tried fuel screw out 1.5 and 3 and 4 turns out only slight improvement any help would be great. p.s. pilots jets are 38's

 

you might try raising the nedles here is a pic if the carb tuning guide that came with my jet kit carb tuning

 

The needls in the stage one kit is set higher and is thiner the the stock one. I hade this issue before I put the jet kit In. It did not have any change at the 3500-5500 range.It did wake up the high RPM,S

 

In addition to raising the needles a bit, you may want to be sure that there are no vacuum leaks. The carbs will not be happy if there is a leak somewhere.

 

YEP, I have checked that to, I even pulled the carbs off a 2nd time to make sure i did not miss any thing. I'm just not sure if the slow jet is the right size.And might be the cause. thanks for the reply jasonw

 

Does any body have another ideas? hase any body had to go to larger than a 38 slow jet or do i have a nother problem.

 

Is the main jet the right size? If the main is off, getting the rest of the settings right should prove difficult if not impossible. Here's where to go for troubleshooting... www.factorypro.com The following is lifted directly from their site. If you still have problems after following these steps, give them a call. They provide positively excellent customer support-and there is no fee other than perhaps long distance charges.

"Follow steps in order....First, dial in:

1. Top end (full throttle / 7.5k to redline -
Best Main Jet must be selected before starting step 2 (needle height)!
Select Best Main Jet
To get the best, most even top end power (full throttle/after 7500 rpm), select the main jet that produces the highest top speed / pulls hardest at high rpm.
If the bike pulls harder at high rpm when cold and less hard when fully warmed up, the main jet is too large. Install a smaller main jet and retest until you find the main jet that pulls the hardest at high rpm when fully warmed up. This must be done first - before moving on to the other tuning ranges.
If the bike doesn't pull well at high rpm when cold and gets only slightly better when fully warmed up, the main jet is too small.
In order to properly tune the midrange and low rpm carburetion, THE MAIN JET MUST FIRST BE PROPERLY SELECTED after 10 to 15 minutes of hard use!
Do not pay too much attention to the low-end richness when you are changing main jets - you still need to be using the main jets that produce the best power at high rpm. You will deal with the low-end / cruise later - after step 2.
2. Midrange (full throttle /5k-7k)
Step 1 (Best Main Jet) must be selected before starting step 2!
Select best needle clip position
To get the best power at full throttle / 5k-7k rpm, adjust the needle height, after you have already selected the best main jet.
If the engine pulls better or is smoother at full throttle/5k-7k in a full throttle roll-on starting at <3k when cool but soft and/or rough when at full operating temperature, it is too rich in the midrange and the needle should be lowered.
If the engine pulls better when fully warmed up but still not great between 5k-7k, try raising the needle to richen 5k-7k.
If the engine pulls equally well between 5k-7k when cooler as compared to fully warmed up, the needle height is probably properly set.
Do not pay too much attention to the low-end richness when you are changing needle clip positions - you still need to be using the clip position that produces the best full throttle / 5k-7k power in conjunction with the main jets (Step 1) that produce the best power at high rpm. You will deal with the low-end / cruise next.
3. Low end (full throttle / 2k-3k)
Step 1 (Best Main Jet) and Step 2 (needle height) must be selected before starting step 3!
Float height (AKA fuel level & how to..)
To get best low-end power, set float height (fuel level) so that the engine will accept full throttle, without missing or stumbling, in 2nd gear from 2.5k to 3k rpm at minimum.
Float heights, unless otherwise specified in the installation guide, are measured from the "gasket surface" of the carb body to the highest part of the top of the float - with the float tang touching but not compressing the float valve spring.
If the engine has a "wet" rhythmic, soggy area at full throttle / 3k-4k rpm, that gets worse as the engine heats up, lower the fuel level by resetting the float height 1mm greater (if the original was 13mm - go to 14mm). This will lower the fuel level, making full throttle / 2k-3k rpm leaner.
If the engine is "dry" and flat between 2k to 3k rpm, raise the fuel level.
Example: change float height from 15mm to 14mm to richen up that area.
REMEMBER, since the main jet WILL affect low speed operation, the MAIN JET has to be within 1 or 2 sizes of correct before final float setting.
Warning: If the engine is left with the fuel level too high,, the e

 

thanks i'll give it a try.

 

I CANT WIN!!! I hade to raise the needle to fourth clip from top to get the cruise to smoth out. but now when i roll on the throtle from cruise it bogs up to 6500 witch it did not do before.

 

I hope someone nows the solution to my issue. Is there somthing else that would cause this that i am missing like valves or timing.