2000 Kx 250

[Wayfast1500]

Hey guys, I'm new here I posted a thread in the into forum.  I have a 2000 kx 250 I picked up last year.  The bike has v-force reeds, full pro circuit exhaust, wiseco piston, moose high compression gaskets, and a uni air filter.  I'm running at sea level.  When I picked it up the compression was very low, and it had no power so I measured out the bore and it was still the stock size.  I believe stock is around 65-66 and change millimeters.  I ordered a stock size wiseco piston, did the gasket set and the bike still was not running correct.  I compression tested it, I had 140 psi, so I figured my Kips valve wasnt adjusted right.  The drum valves move and I decarbonized the slide valve, set it by opening the slide valve full open, then put the gear on it and turned it counterclockwise until it hit the front of the jug and tightened it down.  I have my carb set up with a 158 main, clip in the 3rd notch, stock pilot with the screw 1.5 turns out.  The bike still is not hitting hard in the low end at all, it feels like it has no powerband.  I rode my buddies stock 2000 yz 250 and his bike came right up in 1st-3rd gear without getting on it hard.  My bike can only wheelie in 1st and thats if I work at it, and it quickly drops off.  I've blown 2 base gaskets since the rebuild if that indicates anything.  I'm starting to run out of ideas, the bike has a 13 tooth sprocket on the front so it should come up in any gear. 

[Friar-Tuck]

 Hey WayFast,
 This maybe a longshot but read through this, on the second page the author found is problem and was good enough to post up some piccy's.
 http://www.kxriders.com/forums/index.php/topic,7266.0.html
   The symptoms sound familiar, Can you give us some info on elevation and temps?  I'll have a look over at the Team green jetting chart (should be on the home page)  and see where you are.  It isn't an absolute however has been remarkably close on several occasions.
  Tuck\o/

[95formula847]

Are you 100 percent sure the powervalve is working. I believe a read somewhere that a powervalve could move and look like it was working if you physically operated it but not when the bike was running. I was told to run the bike and take the powervalve cover off the right side and rev it and see if the rod moves in and out. This may be incorrect so someone correct me if I am wrong.

[Wayfast1500]

I am not 100% sure, but I suspect it is since I put a new gear on it and i did see some wear on the gear about 4 months later.  The temps I am riding in are about 60-70 right now, and the ocean is only a half hour so at most it might be a hundred feet or so difference.

[Wayfast1500]

I almost forgot, the bike has always been a hard starter after it sits a few days.  I just pulled the engine out of the bike and am tearing it down to go through every seal and bearing.  Whats a good compression number, I hear my 140 is on the low side on one of these bikes.

[The Flyin Hawaiian]

Maybe a bad stator. I had a KDX that had similar symptoms as your KX. Also had a collapsed silencer core on another KDX that blocked the exhaust and ran really flat, no power.

[Wayfast1500]

anyone know how many ohms I should be getting from the stator? 

[Friar-Tuck]

All I have is the 500 for that year

http://www.kxriders.com/coppermine/displayimage.php?album=lastup&cat=11045&pos=1

Maybe someone has it...
 

[Wayfast1500]

Thanks man, if I'm in the ball park of that I should be good.

[Wayfast1500]

My stator was in that ballpark, I spoke with a shop owner who told me compression should be around 200psi he rebuilds around 160-180.  I pulled the top end, sure enough my cylinder is egg shaped.  I just put a wiseco piston in less than 10 hours ago, would it be more cost effective to have it bored out and re plated, or have a new sleeve put in? 

[Coop]

200psi is high, I would not expect a 10 year old bike to be that high even unless it was a new cylinder along with all new parts. My 125 was at the low end after I just rebuilt it this winter with all new parts; cranks, piston, rings, gaskets, etc. It has about what your bike was reading (140) and will bring the front end up with my 200# on it. When I first got it done it was gutless, wouldn't even pull me around the yard. After some extensive diagnosis I discovered my pipe was clogged. One mouse nest and one dead mouse later the bike now rips, LOL.

[Roostmad1]

Hey guys, I'm new here I posted a thread in the into forum.  I have a 2000 kx 250 I picked up last year.  The bike has v-force reeds, full pro circuit exhaust, wiseco piston, moose high compression gaskets, and a uni air filter.  I'm running at sea level.  When I picked it up the compression was very low, and it had no power so I measured out the bore and it was still the stock size.  I believe stock is around 65-66 and change millimeters.  I ordered a stock size wiseco piston, did the gasket set and the bike still was not running correct.  I compression tested it, I had 140 psi, so I figured my Kips valve wasnt adjusted right.  The drum valves move and I decarbonized the slide valve, set it by opening the slide valve full open, then put the gear on it and turned it counterclockwise until it hit the front of the jug and tightened it down.  I have my carb set up with a 158 main, clip in the 3rd notch, stock pilot with the screw 1.5 turns out.  The bike still is not hitting hard in the low end at all, it feels like it has no powerband.  I rode my buddies stock 2000 yz 250 and his bike came right up in 1st-3rd gear without getting on it hard.  My bike can only wheelie in 1st and thats if I work at it, and it quickly drops off.  I've blown 2 base gaskets since the rebuild if that indicates anything.  I'm starting to run out of ideas, the bike has a 13 tooth sprocket on the front so it should come up in any gear. 

i bet you have powervalves timed incorrectly,what you do is before you put your cylinder on you check by sight the powervalves are fully opening when the rod is pulled out,goodluck

[dirtjunkie85]

a sleeve is definately more cost effective go for LA Sleeve.