2014 CRF250R intermittently dies at low RPM
Posted: Thu Mar 07, 2019 9:31 am
My bike has at least 100 hours on it that I have tracked doing mostly trail rides. I have kept up with maintenance, oil is never dirty and bike is never overheated.
Symptom: You can hear it in this 30 second youtube clip https://www.youtube.com/watch?v=cvqkjy6PxN8. About 15 seconds into the clip I can feel the bike is losing power, I try to "rev out" of it a bit but it dies just the same. This also happens sometimes when I come to a stop with the clutch fully disengaged. This happens 1-4 times over the course of 2 hours of riding and the bike always starts right back up and the bike pulls really hard. Otherwise there are no problems with it.
Troubleshooting so far:
1. New Spark plug, the old one had a rusty nut but looked okay otherwise
2. New CLUTCH
3. Valve Clearance: I checked valves, only one exhaust valve is out of spec and only by .001". The other valves are all within tolerance.
4. Carbon Buildup: I scoped the piston and it was pretty caked with carbon. I did an MMO piston soak and ran it hard, this cleared almost all the carbon from the top of the piston, I can't see the valves but I'm sure hit helped a bit there.
5. The MIL light is not showing any codes when I start the bike but I haven't looked at the light as it's dying.
6. Fuel: I've removed the fuel tank and carefully poured it's contents into another container. I found no debris and the tank looks clean.
7. Air Filter: Replaced
8. Exhaust: No Restrictions
Could one valve being .001" out of tolerance cause this? Could Carbon? Does this sound like a problem with EFI like maybe it's getting too much fuel or not enough?
Please help, I'm lost and I don't want to just start throwing more parts at it without some proof of failure.
Thanks in advance!
Symptom: You can hear it in this 30 second youtube clip https://www.youtube.com/watch?v=cvqkjy6PxN8. About 15 seconds into the clip I can feel the bike is losing power, I try to "rev out" of it a bit but it dies just the same. This also happens sometimes when I come to a stop with the clutch fully disengaged. This happens 1-4 times over the course of 2 hours of riding and the bike always starts right back up and the bike pulls really hard. Otherwise there are no problems with it.
Troubleshooting so far:
1. New Spark plug, the old one had a rusty nut but looked okay otherwise
2. New CLUTCH
3. Valve Clearance: I checked valves, only one exhaust valve is out of spec and only by .001". The other valves are all within tolerance.
4. Carbon Buildup: I scoped the piston and it was pretty caked with carbon. I did an MMO piston soak and ran it hard, this cleared almost all the carbon from the top of the piston, I can't see the valves but I'm sure hit helped a bit there.
5. The MIL light is not showing any codes when I start the bike but I haven't looked at the light as it's dying.
6. Fuel: I've removed the fuel tank and carefully poured it's contents into another container. I found no debris and the tank looks clean.
7. Air Filter: Replaced
8. Exhaust: No Restrictions
Could one valve being .001" out of tolerance cause this? Could Carbon? Does this sound like a problem with EFI like maybe it's getting too much fuel or not enough?
Please help, I'm lost and I don't want to just start throwing more parts at it without some proof of failure.
Thanks in advance!
