I have a 99 250 TB with the reed conversion. My question is, when the engine is cold and I first
start it up to ride. I use the choke and as soon as it starts up I close the choke and just use the
throttle to keep it running. After the engine warms up enough to idle on its own I can run it around
my track a few times to really warm up the engine. No full throttle runs just about 3/4 throttle a
few times. No problems with any of this, everything runs fine so far. So now I take the bike down
my road and go WOT and I get a little bit of a miss. This happens just a few times then it clears
itself and for the rest of the ride it will go from idle to full throttle with no miss at all. I've done a
plug chop test and the plug is a light grey so my main jet is okay. What could it be the needle jet
or something else?

 

You need to look at the plug when you get the miss that you are talkin about.A light grey plug is a little too lean for me.You should be able to get it a paper bag brown color.You may need to drop the clip on the needle a notch.This will give you a little more fuel in midrange to 3/4.Hope this helps.

 

Mine has done that from new, and so has just about every 2-cycle that I have owned. It will load up when it is cold, and the only way to clear its throat is to open it wide up and cough up the hairball, so to speak! If anything it may be a bit rich in the mid to 3/4 throttle and loading up. Check your plug before you go full throttle next time. Then go full throttle to clean it out, check the plug, then ride around in 3/4 throttle, and again check the plug to see if it was indeed just loaded... I believe until a 2-cycle warms up it will be running a bit rich due to the pipe temp and and motor, so it loads up.... Correct me if I am wrong...

 

Thanks for the info CED.

Redbullssg that is what it is doing after it gets warmed up and I run it at full throttle it
doesn't do it any more.

 

Are you burning pump gas or race gas?

 

I'm running c-12. I just did another plug chop test with a new plug and the color was tan.
The engine was warm from earlier and there was NO miss when I went WOT.

 

Sounds like you got it.

 

yep, sounds like it just runs a lil rich( which is good) until the pipe warms up, and is just loading up. It is normal for a 2-stroke...

 

Thanks !!

I just was not sure if I had a problem or not.

 

From your description of the plug, it sounds like you are right on the money with the jetting; maybe a hair rich? Hard to tell with no picture or being there. Good job.