Won't Start, First post not new topic

Well I decided to upgrade my dr350 and get a fuel injected dual sport.  I choose a 08 wr250r that seemed to be well cared for but the bike had sat for 2 years and wouldn't start, could really smell rancid gas.  I bought the bike and got it home and drained the tank, new plug, and fresh gas.  Even holding the throttle wide open you can tell she wants to start and even backfires a little but just doesn't have that umph.  

List of things I've checked

• Used a inline spark tester, have spark
  

• Checked for kink in fuel line and connector under tank for corrosion, looked nice
  

• Checked the wiring harness behind radiator and all the connectors looked good and seated in their mates fine
  

• Battery is on a charger the entire time and seems to crank over well
  

• Pulled the pump out of the tank, from my research it is an old pump the new ones are supposed to have some black plastic on it.  Previous owner told me the pump had been replaced but unsure.
  

• I noticed there is a new part number for these pumps 3D7-13907-11-00....Has it been changed again?
  

When checking the new spark plug after trying to fire I would expect it to have a stronger fuel smell, and at this point I believe the pump is the culprit but could also be the injector.  Would sitting for the two years do enough damage to the injector?

Thanks for the help and reading.

Steve

Can you hear the pump priming when you turn the key? If yes, then the pump is probably not the culprit.

Have you checked the air filter? Try the following: completely remove the air filter, and spray starter fluid in the intake while you're cranking. If that doesn't work either, then it's time to check camshaft timing: the chain may have jumped a tooth or two.

Thanks for the suggestion, I did try and start without a filter to see if it was an air issue. I have not tried the starting fluid, but will give it a shot. Is it common for these engines to jump time, it does have 10k miles on it.

Thanks Steve

No, it is certainly not common for the cam chain to jump teeth, but there have been a handful of reports of that happening, so if all other remedies fail to address the problem, then it might be worth to check this.

Well did some more testing today, I ended up ordering an aftermarket pump and swapped it out. It primes like the stock one did and I was able to see a lot of flow when I disconnected the fuel line going to the fuel rail. I still don't see much if any fuel on the plug so I pulled the injector and tested it with 4.5v to see if I could hear the solenoid clicking. Sure enough it was fine but I setup a little test bench to see how much flow would come out when energized and I really didn't see much. Is there anything that would cut power to just the injector? I have spark and I know I have fuel up to the rail but not sure passed that. I also tried starting fluid but that did not seem to help, I'm going to go pick up a compression tester right now, mine was to large for the spark plug hole.

Compression came back to 30 psi, this is a cold engine with the throttle all the way open. Looks like I'm going to open the side up and check the timing marks and if that looks good the engine is coming out next.

slacker83 wrote:

Compression came back to 30 psi, this is a cold engine with the throttle all the way open.

The spec is 120 psi (minimum 105 psi), so you definitely have a problem.

Your plan is correct: timing first, then piston rings.

Rather than rings, it might be inlet valves not closing due to never having been adjusted. These engines are, in my experience, not prone to clearances changing quickly, but you never know.

Easy to check if it's rings. Pour a teaspoon of engine oil down the plug hole, spin the motor over, then check compression again. If it's noticeably better, you might have stuck or worn rings. If not, probably valves.

Just as a matter of interest, if I leave my bike unstarted for more than a month or so, it is a real bitch to get it to run. It will fire, then stop and refuse to go. I feel sorry for the starter motor.

66T wrote:

Rather than rings, it might be inlet valves not closing due to never having been adjusted. These engines are, in my experience, not prone to clearances changing quickly, but you never know.

Easy to check if it's rings. Pour a teaspoon of engine oil down the plug hole, spin the motor over, then check compression again. If it's noticeably better, you might have stuck or worn rings. If not, probably valves.

Just as a matter of interest, if I leave my bike unstarted for more than a month or so, it is a real bitch to get it to run. It will fire, then stop and refuse to go. I feel sorry for the starter motor.

I have experienced that same issue with mine after it sits for a long period of time.

It will spit or cough once and then I know I am in for the crank fest. Usually I hold the throttle wide open and crank for about 30 seconds and stop.. then repeat. Eventually it will start to sputter - usually can tell when I am getting close to start since the head light flickers on and off. Eventually it will fire right up and be perfectly normal again.

So another day of testing I ended up putting the bike in diagnostic mode and tested the fuel injector, I tested it with pulling the fuel rail and injector together and then running the diagnostic to open the injector. I did this because I noticed the new plug did not have any fuel on it, so I went ahead and had the injector flow tested, the tests came back that it was fine and I should get my injector back soon. Is there anything that can stop the injector from firing? I looked at the schematic and all it tells me is the ecu controls everything. I would assume there is probably some feedback from other sensor that tell what to fire and when.

I have not checked timing yet, after seeing the injector not fire when on the bike I figured that was my problem.

Thanks Steve

slacker83 wrote:

So another day of testing I ended up putting the bike in diagnostic mode and tested the fuel injector, I tested it with pulling the fuel rail and injector together and then running the diagnostic to open the injector.  I did this because I noticed the new plug did not have any fuel on it, so I went ahead and had the injector flow tested, the tests came back that it was fine and I should get my injector back soon.  Is there anything that can stop the injector from firing?  I looked at the schematic and all it tells me is the ecu controls everything.  I would assume there is probably some feedback from other sensor that tell what to fire and when.

I have not checked timing yet, after seeing the injector not fire when on the bike I figured that was my problem.

Thanks Steve

So you know the spark is good right? I ask because I did replace my coil pack and spark plug at one point when I was having trouble.

Another time I actually unplugged the ECM for about 20 minutes since I thought it may reset itself like how a car ECM does. In that case I plugged it back in after 20 minutes and the bike fired right up.

Another time I pulled the tip over switch and shook it. I couldn't hear anything moving in it which may explained why it never really seemed to work before. I found some vent holes and shot some WD40 into it and after that when I shook it you could feel something rattle around. Bike started up after that one too so my guess was that the tip over switch got hung up or had some corrosion which was not allowing a good connection.

Wish I had better info but I see this no start on my bike every so often after a long shut down and there are times I am almost willing to sacrifice a chicken to see if it would help.

Im pretty sure you can test the tip over sensor in diag mode

slacker83 wrote:

So another day of testing I ended up putting the bike in diagnostic mode and tested the fuel injector

Have you seen this video from Yamaha?



However, I don't see how this will help you since you measured your compression at 30 psi. Even if injector works fine, the engine will not start with that low of a compression.

Quote [However, I don't see how this will help you since you measured your compression at 30 psi. Even if injector works fine, the engine will not start with that low of a compression.]

Too true. However, the compression will always be low during the start sequence due to the auto decompressor, no?

66T wrote:

Too true. However, the compression will always be low during the start sequence due to the auto decompressor, no?

Did you follow the instructions in the service manual on how to measure compression? It makes no mention of decompression, so the value of 120 psi is taking account of the automatic decompression.

Hmm. Interesting...

johnkol wrote:

However, I don't see how this will help you since you measured your compression at 30 psi. Even if injector works fine, the engine will not start with that low of a compression.

Good point.. if that is a true reading it is time to start pulling things apart.

johnkol wrote:

slacker83 wrote:

So another day of testing I ended up putting the bike in diagnostic mode and tested the fuel injector

Have you seen this video from Yamaha?



However, I don't see how this will help you since you measured your compression at 30 psi. Even if injector works fine, the engine will not start with that low of a compression.

That video is crazy helpful and I have saved it now, THANKS!!!

I have seen a few forum posts where owners have done a compression test and come back at 30 psi and they attribute it to the auto decompression. I have no idea how to disable it to get a real compression test. I did however take the valve cover off and low and behold the intake cam is probably .5-1 tooth off. I just ordered a manual timing chain tensioner and should have it by this weekend. Hoping to have the timing done over the weekend and hopefully get it to start. Otherwise its going to get serious and a big bore kit will be ordered.

I can't remember if I posted before but I sent the injector off and it was flow tested and cleaned. The shop doing the work said the injector when came in was fine.