2012 WR250R Won't Start after 3 years in storage.

I bought this bike 2nd hand in 2013 & road it for a couple years with no issues (total 1900 miles on odometer).  I haven't ridden in at least 3 years and wanted to get back into it. Original owner installed 4.7 gal IMS tank for mainly road travel & I kept it on for my off road rides. Battery was dead so I purchased & installed new one last week. Fuel had evaporated so I added a gal & then tried to fire it up. Engine turns over but will not start. Fuel pump kicks in when I turn the key on. Kick stand auto shut off unplugged to confirm this was not the problem. If I flood while trying to start then wait a second to start again without flooding, engine sometimes runs for about a second or two but then shuts off. I removed 4.7 gal tank and reinstalled original fuel tank, refilled with clean fuel but same results. I've been looking online, Youtube, and on some forums for help but have't found a good step-by-step to explain how to properly begin troubleshooting. I'm looking for any advice on where to begin, what manuals to purchase (if any), what websites to access. I was really happy to find this forum, but I'm new to forums, so all the answers might be right here once I learn how to use/access it. Any help steering me in the right direction would be greatly appreciated.

Does the bike show any Fault Codes?

Fault Codes sticky

With it standing for 3 years and the fuel evaporating, id be looking at the injector being gummed up, along with a new plug !

I've got the "Owner's Manual" that came with the bike & "2008 WR250RX(C) Service Manual" I found online.

John, I'm new to maintenance & diagnostics on a bike so I'm reading up on everything as fast as I can. No code appears on the display at all & the engine trouble warning light is not on afterward. Under these circumstances, the service manual talks about checking sensors & actuators in Diagnostic mode for: Throttle position sensor, Ignition coil #1, Injector #1, & AI solenoid. I'm reading up on this now but this sounds technique sensitive.

Monkey, thanks for the tip, I will look at these as well.

YouTube video on how to check the Fuel Injector on Yamaha bikes.

First, find the stock service manual. You can find it in hardcopy or pdf form. I have the pdf version.

Chk Youtube for How To's, there are "eh" ones and there are great ones, they give you visuals so you know what you're tearing into.

This was helpful for me running down previous repairs, it's a list of troubleshoot codes as well as a video and description of how to run through each:

http://wr250r.com/articles/diagnostics-mode


I agree with above, it's been sitting for 3 years so I would go with new battery (you already did), new spark plug (CR9EK), new fuel, (new oil). I'd also measure the coil's resistance to be sure it is in spec while you've got it off. The way it sounds about running for a few seconds then shutting off, I'm inclined to wildly guess it's the fuel pump. (Does it sound like a carbed bike running out of gas?) But before replacing the pump, I'd be sure the fuel system and ignition system are clean/new and working as they should. If possible, try a fuel cleaner to run through.

Simply parking a bike with gasoline in it for a long period of time is always a big no-no, whether it has a carburetor or fuel injection.
When gasoline evaporates, it leaves it's heavier elements behind and that is what plugs-up and corrodes parts of the fuel system.
Sounds like fuel is not being delivered to the engine, and that's my one and only guess along with checking the air filter for a rodent's nest.

Whatever the cause and remedy ends up being, please let us know by posting your findings in this thread in order to educate the rest of us and help the next guy.

Latest Update: Learned how to use Diagnostic Mode from service manual & on YouTube (thanks MotoBeto video & Monica's link). Everything checks out fine. The only Malfunction History Code was 30 (from previous vehicle overturn - I did it a bunch). I changed out to new spark plug but still have same problem. Next step is the fuel injection system.

John, that is an awesome Fuel Injection video on YouTube, thank you. I will buy a fuel pressure gauge to confirm fuel pump is working properly and also perform a Fuel Pressure Drop test to confirm injector is working properly. I'll watch some more videos to see if there is a recommended gauge and also make sure I do it right.

Monica, I didn't measure the coil resistance, but I'll go to school on this and check it out. As for you're other tips, thank you. I'm using only new fuel, oil change wouldn't hurt so I'll get to that. Not sure about the "carbed bike running out of gas" similarity, but it doesn't sputter before it turns off, the idle just slows down quickly and dies.

YZEtc, I checked air filter and it looks pretty clean. It sure is acting like fuel is not getting to engine so I'm hoping my next step is revealing.

Questions: With fuel evaporating over 3 years, is it possible the injector inlet filter could be plugged/dirty? Is there any other fuel filter in the fuel line - I couldn't find one in the manuals? Would a fuel cleaner (mentioned by Monica) clean up dirty filters or plugged up parts or would I need to flush the fuel system somehow?

I will update after the fuel injector test test. I cannot thank you enough for your help. I never would have known where to start and I'm learning lots.

Hockeybob wrote:

Questions: With fuel evaporating over 3 years, is it possible the injector inlet filter could be plugged/dirty? Is there any other fuel filter in the fuel line - I couldn't find one in the manuals? Would a fuel cleaner (mentioned by Monica) clean up dirty filters or plugged up parts or would I need to flush the fuel system somehow?

The filter at the fuel pump is the only fuel filter on this bike.

I don't think that the inlet fuel filter is gummed up; even if it were, the new gas would have dissolved any residue on it.

However, if the injector is completely blocked, then the new gas cannot even reach that part, so neither new gas nor fuel cleaner would help. I would expect that you would have to remove the injector in order to thoroughly clean it.

From the fact that the bike did start a couple of times, it sounds as if the injector may be only partially blocked, in which case a heavy dosage of fuel cleaner might help.

Useful video from Rocky Mountain on how to clean a fuel injector:

Update: I performed the Fuel Pressure test after renting & Fuel Pressure Kit from AutoZone & adding a couple components to connect to the WR250R. Starting from 0 psi, then turning on the main switch & the engine stop switch, I could hear the fuel pump turn on. Pressure remained at zero right up to the point where pump shut off (less than 5 sec), and I only saw a minor 2 to 4 psi blip at the very end, but final pressure settled at 0 psi. I was concerned that maybe the gauge wasn't working properly, so I tested with an air compressor and it does work.

This leads me to assume the fuel pressure regulator is not working properly but I'm not finding any good videos or support online. In fact, I'm still looking for a diagram or video to confirm the location of the regulator & replacement, but I'm guessing it's on the top of the fuel pump assembly. Most forums claim that Yamaha only sells the regulator with the full pump assembly which runs about $???. One forum talked about installing the regulator from a YZ250F but says he didn't confirm fuel pressure after installing and then developed problems after 6 months. This regulator is listed on Amazon under "HFP-PR8 Fuel Pressure Regulator Replacement" & claims it works for Yamaha WR250F WR450F/YZ250/YZ250FE/YZ250FX (2012-2018).

Any advice or thoughts on fuel pressure regulator replacement would be appreciated.

I know that you have probably already double- and tripled-checked the fuel pressure measurement, but if the pressure is indeed zero, how could the engine have started even for a few seconds?

If you are certain the fuel pump assembly is the problem, then there is a cheap way to check: get a Kemso fuel pump to replace the OEM one. This obviously will not solve the problem if it is indeed the pressure regulator that has failed, but the OEM fuel pumps have a well-documented history of failing, whereas I have never heard of the pressure regulator failing on the WRR.

Instructions for replacing the fuel pump. A lot of us (me included) have replaced the OEM fuel pump with the Kemso, and to my knowledge no one has reported a failure with the Kemso yet.

Thanks John. I neglected to mention that I opened the bleeder also while performing the pressure test & I was able to pump fuel out the bleeder hose. That's what made me think that as soon as pressure reaches some low value (too low to measure), maybe the pressure regulator sends a signal to stop pumping. Also, the guy who installed the YZ250 regulator, mentioned his fuel tank would leak when he disconnected the fuel line, but when he swapped out with his buddied tank, disconnecting the line would not leak. My tank leaks every time I disconnect the line also, so I'm wondering if this may be a sign of a failed regulator? I'll search some more for any leads on the pressure regulator, but it sounds like I'm eventually going to have to change the pump out anyway. I may just order the regulator I mentioned and a new pump as well (I didn't realize they were so cheap). Can't thank you enough for sticking with me on this.

Hockeybob wrote:

That's what made me think that as soon as pressure reaches some low value (too low to measure), maybe the pressure regulator sends a signal to stop pumping.

The pressure regulator does not work the way you imply: it does not have any circuitry to send a signal back to the pump to stop pumping.

The pressure regulator is a simple mechanical device with a spring-activated escape outlet: if the pressure from the pump is too high, the spring compresses enough that it opens the escape outlet, and gas flows out of the pump assembly back into the tank. There is no corrective action the regulator can take for fuel pressure that is too low. The only way the pressure regulator could fail is if that spring is stuck open and all the fuel pressure the pump generates flows out of the escape outlet; possible, but highly unlikely.

Your tank leaks out of the fuel outlet simply by gravity? Or when the pump is working? In either case, this is not related to the pressure regulator: if it fails, the fuel returns to the tank.

I would advise against replacing the regulator from a different bike: we don't know if YZ models use the same fuel pressure as WRR models.

John, I just finished a long update with diagrams & photos asking how the regulator could possibly work without electrical leads, only to find you had already answered all my questions by the time I hit the send button. I have ordered the pump but it won't be delivered for 2 weeks (didn't see option for faster shipping). So I also ordered the regulator which will arrive in 3 days. Like you say, regulator most likely isn't the issue, but 2 weeks is a long time to wait. I'll update soon.

Oh & to answer your question, I opened the bleed with the pump running. I didn't try it without but it may have done the same due to gravity. I've got time on my hands so I'll try it.

Another question: How does the pump know when to turn off if the regulator doesn't send a signal?

I replaced both the pump and regulator with the Quantum unit kit HFP-390-UR back in March-ish. Works fine so far
I was advised by a motorcycle riding buddy who works as a moto mech in their experience the Quantum units seem to be the longer lasting of the aftermarket replacements. His opinion was factory Yamaha parts were the best and stated I should put them in and keep the Quantum units for spare. But, any unit works until it doesn't, so... buy what you want. When I was searching for replacement pump advice here I saw Kenso mentioned a lot and Quantum. I went with Quantum because it came with a regulator. At the time of my problems I didn't know if it was the pump or regulator so I did both to get into the tank once and get on with life.

Hockeybob wrote:

Oh & to answer your question, I opened the bleed with the pump running. I didn't try it without but it may have done the same due to gravity. I've got time on my hands so I'll try it.

Another question: How does the pump know when to turn off if the regulator doesn't send a signal?

If you got gas flowing from the bleed valve while the pump was running, this means that the fuel pump generates very little pressure (otherwise it would register in the pressure gauge), and the pressure regulator is not stuck open (had it been, the vast majority of the fuel would flow back into the tank).

The pump only turns off when you switch off the motor; as long as the motor is working, the fuel pump is constantly pumping gas. If there is excess pressure in the fuel line, the regulator opens and the excess gas flows back into the tank.

It all makes sense now. Thanks John and Monica.

Update on the bleeder valve test. It does flow with the pump not running if I keep the bleeder valve below tank & fuel level, but no where near as fast as when I have the pump running. I think your diagnosis is spot on. I'll update once I install new pump.

Hockeybob wrote:

Update on the bleeder valve test. It does flow with the pump not running if I keep the bleeder valve below tank & fuel level, but no where near as fast as when I have the pump running.

To be honest, I would not have expected any flow at all, and I think when I had taken my tank apart I had not observed any continuous flow from the fuel outlet.

But if I think about the mechanics of it, it makes sense for there to be a flow if the pressure regulator does not completely block the circuit in the absence of any pressure from the pump.

Maybe some other members can attest whether there is a constant flow even when the pump is not running.

Update - my bike is running, WooHoo. I'm still waiting on the arrival of the new pump but the Fuel Pressure Regulator arrived so I installed it and the bike fired up right away. John's last assessment was correct about the regulator not blocking pump flow back into the fuel tank.

What I've learned: Yamaha OEM regulator claims to be designed to maintain 34.8-36.3 psi fuel pressure while pump is running. My pump works fine but the regulator obviously failed after sitting idle for 3 years. The new after market regulator has been discussed in various forums "Quantum Fuel Systems HFP-PR8 and is sold & shipped thru Amazon for $30. It is only slightly shorter than the OEM but the O-rings fit & seal properly and they have added a small screen on the pump side of the regulator (I still haven't learned how to add photos here). I was curious to know what pressure it regulated (since it's after market & has no specs anywhere), so I decided to hook up the Fuel Injection Pressure Gauge kit. I had to disconnect the fuel line again & this is when the symptoms all became clear. The fuel line was under pressure when I disconnected it, this was the first time since I began this thread. The very first time I disconnected the fuel line with fuel in the tank, there was a small but noticeable intermittent leak thru the fuel pump depending on how I held the tank. With subsequent troubleshooting and disconnecting, the fuel leak increased to a flow as mentioned in the bleeder test. With the new regulator, my tank does not leak at all except for the quick pressure release when the fuel line is disconnected. After connecting the pressure gauge and starting the engine, my fuel pressure read 55 psi. When I killed the engine, pressure decreased to 45 psi & held solid. At this point I also decided to try the Fuel Pressure Drop Test mentioned by John above & includes a Yamaha YouTube link. This test is designed to confirm the injectors are opening correctly and spraying into the cylinder. With the fuel pump electrical connector removed and a starting fuel line pressure of 40 psi, I went into Diagnostic mode and used code 36 to Actuate the injectors 5 times in 5 seconds. After 3 cycles the pressure dropped 2 psi. This can only be performed if your fuel line holds pressure and was one of the tests discussed earlier in this thread to possibly confirm the injector was not stuck open & preventing the bike from starting.

I'm still nervous about a fuel pressure of 55 psi vs 35 psi, so I called Quantum directly to see if they have a regulator with a lower threshold - they do not. The Yamaha YouTube video claims that all Yamaha engines are designed to operate at a specific fuel pressure. If the pressure is too low, the engine runs lean & may sputter during acceleration. They don't specifically say anything about high pressures, but I would infer from this that an engine would run rich. I haven't read any complaints about this regulator but thought I'd put it out there for any feedback.

That's great news Bob, but the fact that the new regulator is set to 55 psi whereas the OEM is around 36 psi is a cause for concern: as you point out, it should result in a very rich mixture. The only counter-argument I can think of is if the additional pressure also affects the injector piston, forcing it to open later and close earlier than normal, balancing out the overall effect.

I'm surprised it was the pressure regulator since it's a simple spring device, but the fact that fuel was leaking without any pressure was pointing in that direction. If you want to do an experiment, spray carb cleaner (or acetone, or Seafoam) into the regulator to see if it gets unstuck.

In order to post pictures you can either host them here (by using the screen icon with the disk), or host them at an external site and link to them by using the screen icon (visible when you compose messages).

I'll see if carb cleaner will restore the original regulator and update. If not, I read on another forum about someone that used a regulator for a 2011 Kia Sportage that he ordered from Rock Auto. It's specs claim ~50 psi. They were able to reduce the pressure rating after 3 attempts, by bending the upper wall of the regulator outward, allowing the spring to expand and hence apply less force to the diaphragm resulting in lower regulator pressure. This was a pretty sensitive operation and he used an M6 bolt to do it. I'm not sure if I'm allowed to post links to other forums on here but let me know and I'll send you the link.

I don't think modifying a pressure regulator at this stage is prudent.

As a first step, just ride the bike and see if the fuel mixture is as rich as the numbers would indicate; it's possible that the design of the injector compensates for higher pressures.