Posts
17
Joined
9/14/2017
Location
Woodbury, CT
US
Edited Date/Time
10/16/2017 11:55pm
Surprise surprises, another EFI CRF hard to start question. I'm going make this as simple and short as possible. Bought a really low easy hour (about 10) 2010 crf250 this June after not riding for about 6 years due to injuries. The bike still had all the original ink stampings on it. From day 1 at the guys house it wouldn't start cold, takes about 20 kicks. The bike sat for about 2 years (bought from original owner). First day I took it out, the bottom end blew on me. There was gas in the oil, caused from a bad/old leaking fuel injector. So I replaced the top end, bottom end, did the valves, new fuel pump, fuel injector, mass air flow sensor, and the EFI killswitch. The only thing I have not replaced yet, but did not look worn, was the spark plug. The timing is spot on, and when its running, it runs great. Its only when its cold it takes forever to kick. It can be 100 degrees and still takes about 20 kicks. Or if I moto then wait 45mins to an hour between motos, it will take about 20 kicks again to start. Over the years I have had 6 CRFs, one being a 2010 that I bought new and never had this problem. Any ideas or suggestions are greatly appreciated!
It sounds like it is set too lean.
There was an issue with the need to reset these back then as they were creating a lean condition starting and dying at low rpms. As I recall they came from the factory at about .5 volts and they had to be adjusted to about .65 volts to help the problem.
I also recall there being a lot of bad kill switches. ( yes I saw that it was replaced, but was it checked?)
Paw Paw
I have not check that. I just looked into it, and I'm ordering the tools I need as we speak. Ill keep you posted. Thanks!
Sitting right at .47. Ill have to crank it up to .65 and see if that helps.
The Shop
Have you tried turning up the idle for cold starts?
If yes to both of these, I would suggest you intake valves are too tight.
FYI: I would also try to reset the TPS to about .5-.52 volts at idle speed.
I would also check to make sure your fuel injector is not leaking.
Paw Paw
If it is a fuel delivery prob, there are a few things that can cause it.
Bad coolant temp sensor or air temp sensor. If either of these is bad, they will not tell the computer how cold it is and richen the fuel appropriately.
Bad capacitor. This is what stores the juice to fire the injection until the motor is running and the stator is providing voltage. If the capacitor is bad it could take excessive kicks to build up enough voltage to fire the injection.
Bad ECM. There is a circuit that runs through the ECM for the voltage to charge the capacitor. You don't need this voltage to run the bike, but you need it to start.
I'm thinking it has something to do with the capacitor or the ECM. Because it would make sense that the bike will start if it has been running recently but after an hour or so the capacitor would be discharged.
As far as the head goes the the valves were lapped, seats were good, leak test was good, clearance was adjusted. Only the left intake valve was out of spec by a thousandth.
I do know a little about electrical and circuits, and the capacitor actually really makes sense when you think about it.
The coolant temp sensor I have not replace yet, but the air temp sensor I have replaced with no change. Ill try the coolant temp first as its a lot cheaper than a capacitor.
Is there a way to test the capacitor, or ECM? Maybe Tokyo mods can run the ECM through some test?
Paw Paw
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