jetting advice - too lean

[StangMATA]

I recently put on a Busa rear shock and hacked up my air box cover a bit to make a good fit. I also have a D&D slip on.

Prior to cutting the airbox the bike ran great. I cut a 4"x4" whole out of the airbox cover (nothing too big) and suddenly I had bad stuttering between 5k and 6k RPM under HARD acceleration. It would go away with a little choke.

I pulled the carbs and gave them a thorough cleaning even though they were spotless. I reassembled the bike and I have the same sputtering.

As an experiment, I taped the hole in the airbox cover. Well, now the bike runs just as it used to....like a rocket.  

Now I want to richen the bike up just a tad. Should I change the jets, move the needle, etc? Someone give me the best advice they can (because removing those carbs is a PITA). Duct tape is not a solution....I need to get a little more fuel in the motor.

[pmackie]

Well Stang...you've got a couple of choices. The 2nd Gen's are pretty lean across the range, and opening up the airbox and putting a D&D can will have made it worse. Since your stutter is under hard acceleration, it is likely the needle or main circuit you are feeling.

Option #1 - get a stage one jet kit from Ivan's or Dale Walker's Holeshot. Most guys here seem to have had good luck with either. Both come with tuning instructions and support to get it working right. IIRC, Ivan's comes with new adjustable needles, where Dale uses shims.

Option #2 - You can duplicate the basics of a stage one kit by doing the following:

a) Idle/Pilot circuit - drill out the air screw plugs and set the screws at 3 to 3-1/2 turns out. This will richen the idle and up to 1/4 throttle performance.

b) Needle Jet - use one or two 0.5 mm shims under the needles. Guys have found small washer packs at Radio Shack. I have some left over (sent to me by Baz) if you want them. PM me your address. This will assist the 1/4-3/4 throttle range.

c) Main Jet - go up one (or more) size on the main jet (one of the 1200 guys could advise actual jet size) You will need to order from your dealer, or online.

If the cost is not a deal breaker, the jet kits will likely help you get it right the first time. If cost IS an issue, option 2 will likely only cost you $30 or less for the main jets, assuming you have a drill bit to remove the plugs, and if 1 shim per needle is enough. (I think I have only 6 shims to send you).

[okbandit]

For the ghetto jet kit, I have used the following.  2" hole in lid, 112 main jet 1 shim (equal to 2 rad shacks) and 3 turns out.  The main jet is the primary player here and very important to make it work. I get mine at Bikebandit.com for $9 a set.  I am at about sea level, as your elevation increases drop the main to a 110.  You may need to repair or replace your lid.  If so I have a spare you are welcome too.  By the way, the bike that is on has a D&D bolt on  and the credit for most of the setting go to FastLarry's webpage.

[PaulVS]

I cut a 4"x4" whole out of the airbox cover (nothing too big) and suddenly I had bad stuttering between 5k and 6k RPM under HARD acceleration. It would go away with a little choke.

If I read this correctly... that's a GINORMOUS hole for the airbox for a bike that is already lean.  Even with a typical stage 1 kit you'd only put about 1/4 of that 'holeage' in the airbox.

And with a slip-on as well?  No matter what... you're going to have to cover up a good portion of that crater in your airbox.... or go with a stage-2 with pods.

[Red01]

And with a slip-on as well?  No matter what... you're going to have to cover up a good portion of that crater in your airbox.... or go with a stage-2 with pods.

...or at least a Stage II kit. I know Dale offers his Stage II for the 2G bikes with pod filters or with the stock airbox. With the stock airbox, he pretty much eliminates the airbox lid... which sounds like what's been done here.