So I just completed a top end rebuild on my 2018 Honda CRF250R, and now after the first break in/ride it keeps shutting off after idling for a couple seconds, and blinking (Mil 1). It only started happening after the 3rd time out on the track, and I've tried everything from: unplugging the kill switch, making sure all of the connections in the cables where good, turning up the idle, checked the spark plug, etc... but the bike just sounds like it's misfiring/skipping a beat, and then just shuts off occasionally. I couldn't imagine it being the valves out of timing or any engine problems considering it only has about 3 hours on the rebuild. (Things I replaced on the rebuild: Valve springs, piston, piston rings, piston pin, piston clips, cam chain tensioner, gaskets, spark plug, etc...) Everything was done by a mechanic.
Have you made sure all connectors around the throttle body are plugged in? There's also an air temp sensor near the air box that people always forget to plug back in as well.
I'm 99% sure all of the connectors are plugged in. I can double check tomorrow. I'll pull it all apart again. But I'll count them as I plug them back in again. Maybe could the issue be weak spark?
So all of the cables where plugged in, and I just ordered up a new MAP Sensor. Hopefully it solves the issue, but one other thing I wanted to mention was; could I maybe have short circuited the plug somehow? cause I ain't going to lie, I did forget to unplug the battery during the rebuild, and it did zap one time when I was screwing in one of the wires on the fuse box thing. But what's also weird is that it wasn't acting up when I took it on the track for the first couple times...I'm just kinda lost. But I'll keep you updated. their is a video on my Youtube channel if you want to get a reference. The video name is, "2018 Honda CRF250R rough idle, shutting off, and blinking (Mil 1)".
MIL 1 is an open or short circuit in the MAP sensor circuit, or a failed sensor. The symptom of those conditions is a poor idle. It's unlikely that your sensor suddenly went bad. More likely: either the plug or it's wires were damaged during removal/reassembly, the plug isn't fully seated in the sensor socket, the wrong plug is plugged in to the sensor. Or it's simply not plugged in at all
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Ok, and I just wanted to say thank you guys for helping me. I really appreciate it. But also, what's weird is that it only started happening on the 3rd time out on the track. So I'm guessing that it wiggled loose some how? But when I took the bike apart again everything was plugged in, and nothing was corroded or anything, and all the plugs looked good. So I know you said it highly unlikely for the sensor too go bad, but I think this is a rare case that it did...or the wire somehow went bad. Idk. What I'm going to do is unplug the battery and ECU for about 20min, and just tripple check all of the wires. If that doesn't fix it then I'm sure it's that MAP Sensor.
I watched your youtube video, and if you’re thinking that 1 blink when your bike shuts off is a code, it’s not. The orange light flashes once when the bike starts and once when the bike is shut off. My wife has the same bike and i just started her bike to confirm this. You are not having a code for a map sensor
That would be normal if it weren't idling rough, and shutting down by itself. Notice in the video that the kill button has not been pushed when the bike dies
Doesn’t matter. You can dump the clutch with the bike in gear to stall it and it will still blink once. The codes are only shown with the engine running
so do you maybe think it's valves?
Ahhh you're correct. I'd forgotten that.
If the valves are set too tight it might flame out like that. If the timing is wrong it generally won't even start
Maybe check the tps voltage. When they fail they can do very strange things
Guys I'm still so lost...I've literally done everything I can to this bike. I brought it to a Honda dealer and even they're struggling with it. They've done everything from checking the valves, doing a compression/leak down test (It all passed), bought a new ECU, bought a new stator, changed the ignition coil, changed the whole gas tank/fuel pump, unplugged the kill switch, cleaned the throttle body, changed the fuel injector, changed the MAP sensor, changed the spark plug etc...I mean the list goes on. I mean wtf could it be??? I'm so lost. The bike just keeps idling for like 10 seconds(ish), and just dying...
Did you check the tps voltage?
No, I just told on of the mechanics that it might be the TPS. So he's going to swap/test it really quick from a new bike. I'll get back to you when he tests it.
Shouldnt it throw a code to the ECU if the TPS voltage was bad though? Cause the ECU has zero codes.
So the shop checked all the voltages on every single wire he could including the TPS, and they're all in spec...I'm at a total loss with this bike. I just bought a new wire harness, and I'm going to clean all the connections, and pack them with dielectric grease, and see what that does. I'm going to also try and clean off the air pressure sensor/order a new one including a coolant temp sensor. The air pressure sensor might have oil residue on it or something. If none of this works I'm committing arson, and throwing the stupid ass bike on the railroad tracks, and I'm buying a Kawasaki. If you could give me any other ideas on what it might be just lmk.
Figured out the issue everyone, and it's the most stupid thing ever...3k gone, tons of hours spent for it to just be a spark plug cap with a tiny hole in it. The spark plug was basically arching to the head at idle speed causing it to flame out...I'm so done. Thank you to everyone that helped though I wish you guys the best!!!
Damn rough piece to have fail. Hope you get some good hours out of the bike now.
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