Guru needed to debunk my jetting practice

[mnnthbx]

The fact is I have no place to do a proper plug chop and varify my jetting. That being said, I realize I'm going about this all wrong, but it's the best I can do. Anyway on to my smeal...

03 200, FMF woods & TCII, DFII reeds. Stock needle in mid clip. 42 pilot. 152 main.

I de-snorkled the air box and drilled 10 1/2" holes in the air box lid.

If I tape over six of the holes my bike runs spot on. If I run all ten holes open, the bike gets a lean hesitation at walking speed if I rip the throttle open.

My logic thinks this:
It must be a bit lean on the main. I say lean because I add air and the fuel can't keep up.
I say the main, because I imagine the extra holes would primarily effect the "max air flow" of the box, which is only relevant at near full throttle.

Make sense.

The easy way out is to just keep the tape on six of the holes as it runs well there, but I refuse to settle on using tape as a jetting tool....

Any input?

 

[dsndblm]

Without doing a WOT chop you will never know exactly where you are at. The too small main jet idea sounds right. I would try and find a place and check the plug . Cooler weather is right around the corner and if you have a lean condition now, it will be much worse if you ride in lower temps.

My 88 is jetted 40 pilot, 152 main, CEK needle, 4th clip position. But, it is also well over 100 degrees here now and a bit humid at that. I use a 155 main 42 pilot and adjust needle as needed in cooler months.

Hope this helps

 

[mikdxer]

jetting

Try lowering your clip on your needle one position and see if that helps, by the way, what elevation are you at there?

 

[Rhodester]

I'm intimately acquainted with your problem! The quickest fix to try is a richer main. Go fat enough and the hesitation will go away...but, you MAY end up too rich on top (I did). Also try raising the needle 1 clip position (lower the clip). I had the best results going with a longer and richer L1 (straight section) on the needle and running it high (low clip position, 4 or usually 5) and keeping the main jet pretty close to where it should be. Longer straight section means a Cxx or Dxx needle instead of the stock Bxx taper. I'm currently running a 42 pilot, AS at 1 1/4 out, and a DEJ/5 needle. I vary between a 150 main (6000' and 70 degrees) and a 155 main (2500' and 60 degrees). My off idle hesitation was also sensitive to the Air Screw. 1/4 of a turn (leaner) can bring my hesitation back. I went through 9 main jets, 5 pilot jets, 3 slide cuts (I currently run a 7), 13 needles and a years worth of testing and logging time to figure this hesitation situation all out on my bike.

All that being said maybe I should have put the air box lid back on and saved myself allot of trouble :-).

 

[mnnthbx]

Thanks alot. I have piece of mind knowing I can use the tape as a crutch if I never get it figured out. I'm going with my gut though and trying the laerger main first.

 

[Rhodester]

That's what I'd do...and then lower the clip 1 position to see how that works.