cr 125 1994 fires and then cuts out!!!

[typergaz]

hi guys am new to this site and am wondering if you could help me?

i have a cr 125 1994 and the problem is when i kick the bike over it fires and then dies!...
i can rev it when i kick it and it revs for a second and it just dies on me.
i kick it again and the same fire then die. :bang:
i have cleaned the carb out tryed new plugs ect.tried disconecting the kill switch with no joy.
it just wont stay running for longer than a second iv tried everything i can think of.
its got a realy good spark when i hold the plug to to engine.
can anybody help me!!!

 

[Bigdogdaddy69]

Is it getting gas? clean the petcock out. make sure air filter is clean and that your choke is not stuck on. Id also say do a compression test.

 

[schmanman]

my friend's yamaha baster was doing that, it was a screwed-up electrical safty shut off. one disconnected wire and it worked great!

 

[GarbatyA4]

Check the spark. If the spark is orange... then the coil is weak/shot. I had a similar problem on my yz125... i took my 250 coil... jimmy rigged it on to test and the bike ran great. So if the spark is orange... its weak.

You want a nice bright white/blue spark.

 

[typergaz]

yeh ist got a nice bright purple spark, and ive checked and cleaned the carb out it was full of fuel iv also tried adjusting the mixture screw to see if it was getting starved of fuel no difference. its got a brand new coil and plug :bang: I just dont no what else to do its as if its cutting the spark off as soon as it fires.

 

[GarbatyA4]

Well... so far you have:

Cleaned Carb
changed plug
changed coil
you've checked for carb boot leaks?
change plug again, as urs may be fouled/wet?

I'd check the fuel delivery. i.e. fuel line, and make sure ur tank isn't clogged at the petcock(fuel valve)

Use clear line, and check to see if fuel is rushing through the line. If not then its ur fuel.

I'd investigate the ignition box and or stator.

I'd also unhook ur kill switch until you find the problem.

Good luck and keep kickin, make sure you wear boots, cuz ur running shoes will have a nice hole in em.

 

[typergaz]

yeh it got a clear fuel line and its flowing ok i take the plug out and its slightly wet but still shiney new and still sparking blue i just dont know think am going to have to take it in to a bike shop!!! its just the cost im not looking forward to. someone has said it could be the crankshaft oil seal but i cant see that being the problem and dont realy fancy stripping the whole engine down

 

[kerling]

test to see if your carb is actually doing its job by seeing if you can get the bike to run from using a spray bottle with gas, squirting into the carb.

 

[anthony96rm250]

my rm250 had the same problem it was the spark plug / check if it is getting gas or maybe one of your jets is clogged in the carb and if your throttle cable is not bended or cut or something like that or the carb not getting air from filter dirty??

 

[typergaz]

i just dont get it everythings as it should be checked and double checked the carb stripped it down twice now! got a new airfilter and another new plug today just in case still the same. its like when my transponder reciever in my car broke the ecu would let it fire and then it cut it out because of the immobiliser would cut in but this is a field bike and it doesnt have an immobiliser!!! :bang: :bang: :bang:

 

[Blink-182]

have you checked the reeds?

 

[whenfoxforks-ruled]

When it dies out, yank the plug and look at it. Dry or wet? Wet, your getting too much fuel, or not enough air, or a retarded ignition. Plugged pipe, worn main bearings, sheared rotor key, where all the electrical componets are bolted to the bike, clean and retorque, float valve and or seat, or some idiot modded your engine and or carb. Dry, gas cap not vented, float height, main bearings, timing, detonation, air leak, or some idiot modded your engine and or carb. Has the bike ever run correctly? When was it last rebuilt?

 

[typergaz]

tried my mates cdi unit off his cr 250 and it fired straight up thats what the problem thanks for all the help guys :cool: