2002 RM 125 misfire

[dwaltmad]

I just bought a used 2002 rm125 with a Bill's pipe/silencer and v-force reed asm. I am perplexed with a high rpm misfire that I can't get cleared up. HELP! I've inspected the reed and cleaned the power valve asm. replaced the piston & ring, checked the rod for play, checked the timing mark, cleaned & oiled the filter and tried the following jets: 30, 27.5 25 pilot, 490,430, 420 main, stock needle in all positions. I still get a misfire a high rpm. Any ideas would be appreciated.

 

[bclapham]

next time you post somthing like this try the mods + repair forum!:)

weak coil, wrong plug, bad connection, bad CDI box, timing off, keyway sheared, carb blockage, wrong float level, check the tube on the top of the gas cap for direction. also, check the carb manifold for airleaks- a common problem on bikes with v-force where you have to butcher the manifold.

good luck

 

[Senior KX Rider]

moved

 

[tre633]

Hey, i have an 02 RM 125 with a very similar problem. I bought it brand new last year. About a month ago, after a rain race, it started acting up. I know you've checked some of these things, but here's the list of what I've checked (I still have no solution):
check the core on your silencer that it's not cracked
cracked reeds, or not seated correctly
ignition timing
crud between the flywheel and magneto
float level
grain of sand or anything in float bowl
crud in the slow jet (pilot jet)
blockage in the fuel intake of the carb (take out the fitting that the float shut off valve fits into)
dirt in the gas tank (take out the petcock and check the filter)
coil
CDI
may be the clutch-side crank seal (fouling plugs?)

I don't know if this helps, but let me know if you figure anything out, because like I said, I am having a very similar problem -- tre633@motocross.com

 

[symen]

try a new sparkplug. and check if it doesn't run too rich.

 

[symen]

if it doesn't stop, check sparkplug cap and cable

 

[_j0kA_]

i have a 2001rm125 and experiencetop end misfire when i sucked a little dirt into the carb.. i had to clean (should replace them) the reeds and it cleared up.. although you've already said you checked them, make sure they are in properly (flush with the cage).. other then that i have no idea..

 

[john stu]

maybe its just running too rich on the main jet?try a smaller main and see if it runs better