I am the origional owner of an 87 TRX250R. It has boysen reeds & roost boost. It has sat about 6 years without being ridden. Mainly because at the time, the carb leaked out the tube & after several rebuilds with new floats, needles & seats it kept leaking. So it sat. I finally moved to PA & have room to ride it again & am trying to get it to work again. Of course when I tried to use it it leaked still. So I got a used carb off ebay that looks like it is in good shape. It does not leak now. A few weeks ago I got it started but it kept fouling plugs like within a few minutes. It would run so-so but it would bog down & had no power-band and would eventually die. If I sand blasted the plug it started right up again. The spark looks weak, like a purpleish color not a good blue looking color from what I recall it used to be like. I'm at a stand still right now not knowing where to go from here. I have a volt meter and can test connections, but I just need someone who knows the bike & what readings should be normal. If anyone is willing to help me bring this bike back to life I'd really be greatfull. I am online allot and look forward to any help.

 

Sounds to me as if you're running to rich on the carb. Try popping the airbox off, or worse case the air filter if you don't have a box, just dont run it long w/o the filter. See if it runs any better. If it does then you're too rich in the carb. Read this for info on jetting. Now if those things don't work, then you're probably too weak in the ignition department and I can't help you w/ that. I suggest going to here and buy a service manual. It should answer all your questions and then some.

 

Thanks for the tip, I just ordered a service manual and will check that out.

 

Hope this helps:
1. stator resistance as per Ricky Stator >>> 180-190 ohms
stator resistance as per Clymers >>> 50-200 ohms

2. pickup resistance as per Ricky Stator >>> around 115 ohms
pickup resistance as per Clymaers >>> 50-200 ohms

It sounds like you are fouling plugs due to a weak spark ..... not uncommon on an R.

Also try doing a search in R-Central.com, TRX250R.org, and EXRiders.com

 

Could it be the coil ?

 

yes.........and also a bad cdi although its hard to verify this unless you swap out another known good cdi due to no test specs given in manual. i had this problem a while back when 1 part started failing one after another in a span of a year so i decided to get the CR250 kit sold by ESR.

 

Throw the roost boost in the trash can. your bike should run fine after that or you might need a new cdi box. how long have you been using the roost boost?

 

I added the roost boost when the bike was about 2 yrs old. It gave it much better top end performance at the time. I disconnected the roost boost & it is still the same. I am still waiting for the manual to arrive.

 

Hey i have an 1985 atc 250r that had the exact same probs u are having. The reason we were leaking gass is cause the floats were set lil to high n if u shoke it much it owuld leak so we lowered them lower than the book said no much just a little. The plug fouling we sovled almost mainly by puttin the hottest plug we could n it. I think we went one higher than the book calls for and we start using bean oil and mixing it 44:1 and i havent fouled many plugs only when i idle around alot n dont rev it up.

 

I got the manual & tested all the connections and everything is within specification & points to a bad cdi unit. There are no specifications in the manual on how to check the actual cdi unit itself. Anyone know where I can get a new one online? I don't really want to order a new one from the dealer & pay top dollar for it.