Got a friend with a lt250r, the carb thats on it is a 38mm keihin, has boysoin (bad spellr) power reeds, its bored 20 over and has a paul turner head pipe with fmf exhaust. the bike runs good, but there is no powerband, most 2 strokes there is the power burst in each gear, well this one doesent have it, its not that slow, it will do around 60 and it sounds like its running fine but she dosent have that grab like 2 strokes are notorius for, any info would be greatly appriciated, ppl @ dennis kirk to him to play with the carn needle and raise or lower th clip, I dont remember which they said. Thankx all

 

check the sprocket sizes on the bike also check the compression

 

Have you checked the jetting in the bike? Do a plug chop and check the color of the plug. Check the compression also, like Exotic said. The stock gearing i believe is 12/42, a 13 on the front won;t hurt, but it should go a lot faster the 60

 

Dernit, I was hopin this was somebody looking for an acual, physical "powerband" inside the motor! Sure is fun messing with someone looking for the "powerband", I used to tell them it was this little orange rubber band between the carb and the cylinder...
Check compression, do a plug chop (with a new plug to be sure)-a plug chop is when you get the quad warmed up, make a high speed, high RPM run, killing the motor (first of course) and pulling the clutch in while at a fairly high RPM. Also, some other hints to the jetting would be how well it idles, how often and how easily it fouls plugs, etc.. It should be fairly strong, with a GOOD midrange hit..Also, the exhaust valve could be sticking, that WILL make one run like crap too.

Greg Coats
'87 LT250R
'00 Rancher ES 2X4

 

thankx 4 the info, but 1 question, what do the colors mean? tan is what good?
how about black or white?

 

Black is to rich, and white is to lean.

 

Yeah, tan is the color your aiming for. You didn't say what year the racer was, if it's 87 up it has the powervalve. How does the bike start? A two stroke is a simple machine to work on, and following these tips will get you right where you need to be. Later

 

Black, sooty is bad, it can mean anything from too rich oil mixture (common), too rich pilot/needle and/or main jet (fairly common), or bad crank seals (it happens, means bottom end rebuild time). Tan is what you want- a medium tan with no deposits. If the plug is more whitish looking, and ESPECIALLY if it has metal "specks" on it, it is very lean and should'nt be ran until the problem is fixed. Also note that if you do a plug chop with an older plug, especially if that plug has done a lot of lower RPM running in it's lifetime, it will appear to be running richer than it actually is- so it's best to use a new, or newer, plug. Some of the spark plug manufacturers websites may have a plug reading chart availible online with pictures, that will help you understand what you're looking for better. Also, most any repair manual, be it automotive, quad, motorcycle, etc. will have a plug reading chart inside somewhere.

Greg Coats
'87 LT250R
'00 Rancher ES 2X4