Crf 450 won't start...

[fox128]

My 2009 crf450r snowbike will not start. I put it back to dirt this summer and it ran great until it all the sudden wouldn't start. The last time it ran it took a while to get going but it ran fine.
I had valves checked and adjusters even though they were in spec. It is in time also.
It has 50lbs of fuel pressure.
Stator is good
New spark plug (has spark)
It has dobeck auto tune but when I unplug it there's no change
I've checked the ground location on the right side.

Took it to a guy who says it might be the throttle position sensor but don't know what he's basing that on, and I would think it would still start?

What else can I check or how can I further diagnose? Could I pull the injector out and see if it sprays when I kick?
May have to take it to the Honda dealer for $100/hr but if they can fix it guess it would be worth it.

 

[s.back]

I would do a compression test and leak down test on the valves just to rule or base engine. Could have jumped time and a leak down test will tell you if you have a valve issue.

 

[fox128]

I would do a compression test and leak down test on the valves just to rule or base engine. Could have jumped time and a leak down test will tell you if you have a valve issue.

Timing marks all line up and sure seems to have plenty of compression, but I'll add it to the list

 

[tech54K]

My 2009 crf450r snowbike will not start. I put it back to dirt this summer and it ran great until it all the sudden wouldn't start. The last time it ran it took a while to get going but it ran fine.
I had valves checked and adjusters even though they were in spec. It is in time also.
It has 50lbs of fuel pressure.
Stator is good
New spark plug (has spark)
It has dobeck auto tune but when I unplug it there's no change
I've checked the ground location on the right side.

Took it to a guy who says it might be the throttle position sensor but don't know what he's basing that on, and I would think it would still start?

What else can I check or how can I further diagnose? Could I pull the injector out and see if it sprays when I kick?
May have to take it to the Honda dealer for $100/hr but if they can fix it guess it would be worth it.

I got the same issue good thing Ifound this thread

 

[wwillf01]

ECU swap to see... Obvious things like fuses ...

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[up-high]

Crank it over a few times and check spark plug. If its dry its not getting fuel(either no supply or injector not firing). If its wet it not getting enough spark to fire.
What do you mean all of a sudden it wouldn't start?
You get some dirty fuel? Maybe plugged a line o filter or injector?
Old fuel maybe ?

 

[harooch]

I have a 2010 and have same issues. Have replaced so many parts it's getting silly. Took to dealer, they said my wiring harness is fried due to moisture. Couplers from harness to fuel pump and kill switch are burnt. Also had to do my fuel pump last year. So I'm going with a new harness now. Will let you know if that fixes it. BTW, have full compression on new top and bottom end, new valves (in spec) new plug and lead, new condensor unit, new stator and flywheel, new injector. None of that solved my problem. The fuel pumps are known to be faulty on these bikes. I replaced mine last year with an after market one off eBay for $40. Tested that too cause thought it might have failed, but it is running fine. Must be electrical, so I'm thinking the harness is the culprit. Like I said, will update as soon as that is replaced. This is my last straw though I think. If the harness doesn't fix it, I think she is going in the discount column on the old Craigslist.

 

[fox128]

ECU swap to see... Obvious things like fuses ...

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Where are the fuses?

 

[fox128]

Crank it over a few times and check spark plug. If its dry its not getting fuel(either no supply or injector not firing). If its wet it not getting enough spark to fire.
What do you mean all of a sudden it wouldn't start?
You get some dirty fuel? Maybe plugged a line o filter or injector?
Old fuel maybe ?

Had not thought of that method thanks

 

[wwillf01]

Where are the fuses?

Dont know for your bike but for the yammy which is a different set up they were under the seat....

 

[J&L Snowhawk]

Quick test is give it a shot of starter fluid right into throttle body. If it fires and dies your not getting fuel.

 

[flabbajabba]

my 2010 crf 450r didnt start once. i changed spark plug shimmed valves kicked it until i was mad enough to tied it behind a quad dragged it around the yard long enough that motor was warm (lol) still no start i pulled spark plug and squirted gas down spark plug hole (huge pain) started first kick and i have no idea what it was hasnt missed a beat since its like the efi fell asleep and prime woke it up

 

[TopherDunbar]

My 2010 did the same thing and it ended up being two things: the coil and the kill switch. Mine would start but take like 30 kicks to start but once running would run great. Weird....


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[J&L Snowhawk]

Report updates

 

[fox128]

Here's an update but it's not a good one. Picked up my bike from the private mechanic, he's stumped. His best guess is ecu or injector. He says bike has no fuel or spark. If that's true than it's probably not just the injector but what do I know. He claims to have tested the Cdi and it was good.

Would a bad ecu cause no fuel as well as no spark??
I kicked it over and pulled the plug and it was perfectly dry, so obviously not getting fuel.

I'm about ready to take it to the stealership and let them have at it for $100 an hour because it's a pile of scrap the way it sits.

Can you tell I'm frustrated??

 

[s.back]

No spark and no fuel usually means no crank signal. I would do a good inspection on the wire harness , check connectors for corrosion, and take a good look at the crank sensor. You could have a open in the harness or a bad crank sensor. I no in the automotive field brain surgery usually doesn't fix problems.