Through round-abound means (Thanks Gary! Thanks Bill), I just put a "Bill Blue TM34" pumper on my bike, and I'm working on getting the jetting set properly. Bill does a GREAT job, and the installation was a proverbial "drop-in". (Literally, though, its about as easy as installing the stock CVK, and most of us already know how "easy" that is! )

Anyway, the carb came with a 127.5 main jet, and for my setup, I'm thinking a 137.5 or 140 is where I need to be, which brings me to the point of this post - the "other" reason for getting a pumper is changing jets is so much easier.

Before installing the carb, I replaced the Philips screws with hex head cap screws. I read somewhere this was a good idea, and I had them, so why not. Anyway, when I went to change jets, instead of the classic "top-down" approach ...

1) Remove the side panels
2) Remove the seat
3) Unscrew the fuel petcock
4) Remove the tank
5) Unhook everything from the carb (hoses, cables, TPS connector)
6) Remove the carb
7) Unscrew the float bowl
8) Change the jets
9) Repeat everything in reverse to reassemble

... I took the "bottom-up" approachand left the carb in-place:

1) Remove the right side-panel
2) Remove the exhaust system
3) Unscrew the float bowl
4) Change the jets
5) Repeat everythingin reverse to reassemble

The TM33 has much more room underneith to work around, and the hex head screws make removing and tightening a breeze (although the left rear float bowl screw is a little cramped to get at). Just be careful not to overtighten the screws, which is easier to do with hex head screws!

Anyway, for me, removing the exhaust system from below the carb is a whole lot simpler thanremoving everything from above the carb.

So for anyone that has a Mikuni pumper,this might be an easier approach to changing jets. And for anyone who doesn't yet have one, this is another reason to get a pumper!

Mike

 

Great tip,Mike. Congratulations on your new pumper too. You're going to love it.

As for jetting, I was at optimum mixture with a 140 main and 37.5 pilot with my 331 and a Muzzy with quiet core...actually, we did the runs without the core so we could insert the exhaust probe. Boy was that loud!

Anyway, if your bike is stock, you may not need the 140. Probably closer to the 130 or 132.5 would be my guess. This is assuming an altitude near the 1200' we are at here in Oklahoma.

Another thing to watch if you're having hesitation problems is the w.o.t. stop. I had my stop set too high and it pulled the slide too far up, causing a mixture wipeout. Just make sure your throttle isn't pulling the slide too high.

Good luck!
Bill

 

I've got the KDX snorkel, Twin-Air Backfire resistant air filter, removed the backfire screen, and a Big Gun with Quiet Core insert (not the Vortex Insert). I'm at around 350'-400' elevation.

My local dealer didn't have either a 137.5 or 140 main jet in stock (Mikuni LARGE round), but he had a 138.8 SMALL round, which his mechanic said would work just as well. He said I could return it if I wanted, so I had nothing to loose. Anyway, its much better than the 127.5, but I think I still need to go up to the 140. I picked up a 40 pilot, but I don't think I'm going to need that.

Thanks for the tip on the throttle stop. BTW -What is the stock needle setup, and if its adjustable, is it adjust by removing the front of the carb, or through the top?

 

Hey guys,
Got a pumper carb question.I have the parts to make the 250 a 292 in the near futurewith the intention of going to the bigger bore at the end of the riding season. I am running the muzzy pipe, K&N filter, backfire screen removed, and crankcase vent modified. Question is, what carbdo I get that willwork for both bore sizes, who do I get iffrom, and can I still use the stock throttle? I am planning on leaving the gearing stock. I do most of my riding on the street with a little dirt road and trail riding now and then.
Thanks.

jb7

 

Bill Blue's TM 34 will work well on both the stock and bored KLX. It begins to get a little small if you're cammed and running near the redline on a 331, but that's a bit extreme for most setups. With your 300, the TM 34 will work great.

Bill Blue can be reached at 316/640-3629 (cell) or
316/265-1144 (home).

The needle clip is accessed by pulling the carb top and proceeding from there. We each have our favorite method of pulling the carb, so pick yours.

I use a Dewalt 18 V impact. Very controllable. Install an 8mm deep socket and go to town. I can pull the shrouds, seat, tank, petcock, loosen inlet and outlet screws, pull the cable mount screw and extract the carb through the top of the frame in under 4 minutes. I never touch the pipe or brake cylinder with the TM 34 removal.

Bill Dragoo
Norman, Oklahoma