'holistic' I like it! I may have to borrow that from time to time

 

hmmm this all makes me think, we really got to find someone to fab up a supercharger

 

The closest I've seen so far is a turbo DRZ400[8D] Not sure I'd want to go through all the trouble though. Aside from going with a completely different piston and carburetor, he had to mess with everything from oil flowas well asmultiple attempts at getting routing of the plumbing just right.

NOS would be much simpler

 

The reason I had him put the stock snorkel in was to see if the bike would run better or worse. If it ran better, it meant the bike was running lean, the snorkel richened it. This lets you know you need to go richer on the main jet. Then you put the KDX snorkel back in & see if it needs to be jetted a little richer yet. It's a trial & error situation. The carbs are run on myKLX it is still stock at this time haven't had time to change it yet the only thing I have done to it is put the TM33 carb bored out to 34 MM on it. So all carbs will need to be tweeked to work on your own bikes.

It's hard for me to pre-jet acarb as there are too many variables. We are finding out the openpipe doesn't haveenough backpressure.

We made a quiet core for Bake'sHMF pipe, using a Yoshimura quiet core for the first try. Steve has wrapped it with muffler packing to quiet it down & get some back pressure in the pipe.Steve will post on this later.
Bill

 

ok then the bike ran a lot better. so rejetting is neccessary so back in I go. i've readsome of what you guys are putting in as far as main jets go so i think i'll start with a 135 as my base line. what i'd like to know now is what pilot jet you all suggest i start with?? i'll fine tune the air/fuel screw after i get these larger jets in there.

 

or should i just work on the main first? get that right then go to the pilot jet? the bike started real hard so Bill says that i need both jets (which is fine) but should i do both at the same time???

 

I would trust Bill. I did some more research and found out that Marty was running a 137.5 main jet with the 250cc jug which he said ran very well...in his words..."pulls strongly all the way to the redline"He also had thesnorkel removed. If you plan of removing the entire lid, I recommend a 142.5. That's what I'm running with right now.

 

Everything I've read about tuning CV carbs says start with the main jet and get 3/4 to WOT dialed in, then tweak the needle for midrange performance, and then worry about the low end. This article talkes about adjusting float height and mixture screws, but pilot jets probably fall into that category as well: http://www.factorypro.com/tech_tunin...m_engines.html

The pumper carb isn't the same as a CV carb, but the principles are probably very close, so the same approach should apply.

 

vbrep_register("2878131")
[/align]This is a re-post from the jetting expert Eddie on ThumperTalk. It may help with getting your jetting dialed in.The Mikuni pumper is like the FCR as far as setting the pilot.This has always gotten me real close.[/align][/align]how to confirm your pilot circuit setting [/align][/align]seems like the most common jetting issue that comes up are pilot circuit related.the following is a sure method to choose the needed changes.

with the bike warm and idling turn the fuel screw in till the idle drops/misses.then go back out till the idle peaks/smooths.

this should happen between 1 and 2.5 turns on a fcr carb and 1 and 3 turns on a cv.

if you end up at less than 1 turn you need a smaller pilot jet.more than 2.5 (or 3 turns on a cv) you need a bigger pilot jet.

choose the appropriate size and retest.[/align]

 

That would be great, but it's bear to get at the fuel screw of a flatside pumper while it's on thebike. The only way I was able to do that is I bought a specialized, bevel gear driven offset screwdriver made by Motion-pro.