Why wont my 2010 CRF 250 Cold Start

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9/14/2017 5:20 PM

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!

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9/14/2017 8:11 PM

Have you reset the TPS?
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

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9/14/2017 9:45 PM

Suspect

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much ty. How to spot a paid forum poster/artificial forum traffic producer (see list of actions/phrases below):

Copius pattern amounts of phrases like “Anyone have”..., “Anybody know?”.... and their variations.

Thoughts?
Any help is appreciated!
Thanks in advance!





9/15/2017 5:14 PM

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!

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9/21/2017 7:35 PM

Photo

Sitting right at .47. Ill have to crank it up to .65 and see if that helps.
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9/25/2017 5:34 AM

Ok did some testing over the past few days on this. I set my tps to .65 with the same results. Came back the next day, set it to .55, same results, then went down to .4, same results every time, 15-20 kicks when cold. I did this over a few days so I could replicate a new day of riding. Checked the plug and gap, was perfect, and Im getting great spark. Im fully stumped on this! It only takes a kick or 2 to get going throughout the day when doing motos. Ignition re-map??? Anymore suggestions are helpful, thanks!

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9/25/2017 6:02 AM

When you say you did the valves, what exactly did you do? Did you just adjust them? Did you put new valves in without cutting the seats? Did you get new seats put in? Did you do a leakdown test? What quality of gas are you using? A lot of guys i ride with have problems with regular pump gas just flat out not working for them. I know its basic stuff but a lot of times you just overlook something really simple.

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2009 Kawasaki KX450F
2009 Kawasaki KX250F
2002 Suzuki GSXR 600

9/25/2017 9:33 AM

Are you using the enrichener when attempting cold starts?
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

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9/25/2017 1:09 PM

Have you tried using starting fluid when it is cold? Try that and see if it fires right away. If it does, you've at least narrowed it down to a fuel delivery problem.

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.

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Powerband in every gear !

9/26/2017 6:38 AM

This is great thanks for the help guys.

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?

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9/26/2017 9:58 AM

FYI: You donot lap valves in these bikes as it will destroy the valves coatings and thus reduce their life greatly.

Paw Paw

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9/27/2017 9:22 AM

Had an issue with my wifes bike, it was the fuel pump slowly failing over time. It would take forever to start cold, then would start warm since there was some pressure left when shut off. I replaced the fuel pump and injection just to be safe, it starts up well. Dont hold me to but I read the 2010 fuel pumps have issues, The one ordered was for a 2016 250 (replaced it last year)

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1985 XR80
1999 CR125
2002 CR250
2003 CR125
2013 CRF450
1996 CR500
1998 VFR800

10/9/2017 5:50 AM

We have a winner! FGR01 was right about the coolant temp sensor. Went through all other steps. Checked the capacitor, was holding 5v, ruled that out. Spent the $20 on the coolant temp sensor, and went riding 2 times since and fries up between 2-5 kicks no problem. Thanks for all the help guys!

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10/9/2017 11:07 AM

Bhack711 wrote:

We have a winner! FGR01 was right about the coolant temp sensor. Went through all other steps. Checked the capacitor, was holding 5v, ruled that out. Spent the $20 on the coolant temp sensor, and went riding 2 times since and fries up between 2-5 kicks no problem. Thanks for all the help guys!

Sweet !!!! Awesome that it was the smallest and least expensive possibility.

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Powerband in every gear !

10/16/2017 7:01 PM

Paw Paw wrote:

FYI: You donot lap valves in these bikes as it will destroy the valves coatings and thus reduce their life greatly.

Paw Paw

This^

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10/16/2017 11:54 PM

if you ever wanna check to see if the capacitor is working just unplug it and run power to it

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IG @jaredkeller96