CARB JETTING- old topic, new user

[adam_mcmahon]

i'm asking this as i am in a bind and KNOW someone knows what is happening. actually i know whats happening but someone knows how to fix it

i got a 99B6 with a D&D Race Pipe new K&N Filter, along with NGK Plugs. it seemed to run a *little cold* but now i got a bright idea to cut a bigger window in the airbox to let more air in (mistake) ((i'm actually fixing the mistake tomorrow)) i accelereate and about 4000-5000rpm its hesitates.....BAD (have to choke to get past)  but this leads me to think that i need to rejet. what do ya'll think?

What Jet Kit would be best for this situation. like a HoleShot or DynoJet as i've never bought one. i just want it to run right again.
i'm completely open for any suggestions and eager to listen to experience


adam

[Red01]

You took a bike that already runs lean out-of-the-box and made it even leaner by adding the slip-on AND a K&N filter.

You NEED a jet kit!
Holeshot, Ivan's or Factory-Pro - whoever has the best deal at the moment.
Don't know about Dynojet & the B6 - but on the B12, the Dynojet is the least favored and most difficult to get to run smoothly.
(Some get them to run perfectly, most do not.)

[chupacabra]

I already had a K&N and advance so I went to radio shack and got some washers for $1.00 and shimmed my needles up some. It ran alot better but not perfect. I then ordered two #100 main jets for $17.20. I just got them so I'll install soon and let everyone know the results. When I install the jets I'll drill out the plugs and set the air/fuel screws to 2.5 to start and adjust from there. Unless you buy a kit that has needles I can't see spending $80 or more. But thats just me.
 

[snofrog]

you either need to move your needles up or just get smaller needles also larger mains and your idle enrichment system is going to be lean so work on backing out the screws and maybee larger pilots if you still are having some low speed issues .sorry i cant give you any #s but you will need to work on those circuts M

[99er]

Dude,
The B6 needs a little needle raising, it's true, but mains ALWAYS come first. The mains feed the needles. You need to increase your mains until she can take full throttle to redline, period! Only then should you play with needles and pilots. If you're cheap like me and don't want to spring for a jet kit as it's a challenge to properly jet, I would, myself, go up 2 steps for pipe and 2 more for K&N as a start. I'm assuming that jetting is stock at this time. The size of the hole drilled plays a huge role so you can only change jets and ride/evaluate. Mains cost me $10 for 4 so it's cheap to experiment. Adding a 2" hole and pipe to the B12 takes you up 10 sizes, from  102.5 to 127.5, so you get the picture.
Once she's good on full throttle pull to redline, cruise in a high gear for loading and listen and feel to see if she is surging. Add one shim at a time to the needles to get rid of this. Adjust the screws for smooth idle.

Last, this would be MY humble approach. It may in no way apply to you. Just my approach so - YMMV.
Marc/Atlanta

[Steve]

Adam,

You need to correct what is wrong.

If you are stumbling on midrange, and you increase the Mains to correct it, you may well end up very rich on the top end to get correction at midrange by changing the mains alone.

Best fix is to get a jet kit from either Ivan or Holeshot. Next best would be to shim the needles a bit and reset the idle air screws.

You really don't want to choke a warm engine. If you can't do the jet kit right now plug the new hole in the airbox. Ride it. If that is not good enough try putting the old air filter back in (you might blow it out first) and see what that does. Most likely that will hold you until you get your carbs jetted.

Paul is right on, you leaned out an already lean condition. What your respondents dissagee on is how to correct it. You won't go wrong with a good jet kit.

Steve