fuel pump problem

Thanks to Johnkol for is excellent post. I put in a new chinese pump today using his tip. Easy peasy

My Thanks as well Johnkol.  My WR250R pump failed over time - sometimes it would prime and start and sometimes it wouldn't regardless of temp.  Eventually it just wouldn't prime at all.  Followed your procedure and replaced it with an ebay $30 AU unit (even came with a 3 year warranty ) All back together and started first crank after sitting for several months.  Thanks for you time and effort in putting together a well documented procedure.

Any update from Kemso fuel pump users after a few years? The kit for a WR is currently $26 shipped on eBay, seems too cheap to be good quality, but a few searches reveal some good reports on overall Kemso reliability. Just curious if the conditions that kill the OEM pump also wear out the Kemso.

About to install an IMS 3.1 and considering installing a Kemso at the same time, for $26 its a low risk move but dont want to disassemble the pump cage twice if these are junk

asphaltaddict33 wrote:

Any update from Kemso fuel pump users after a few years?

Three years and 7k miles later, and mine still works without any problems.

asphaltaddict33 wrote:

Any update from Kemso fuel pump users after a few years? The kit for a WR is currently $26 shipped on eBay, seems too cheap to be good quality, but a few searches reveal some good reports on overall Kemso reliability. Just curious if the conditions that kill the OEM pump also wear out the Kemso.

About to install an IMS 3.1 and considering installing a Kemso at the same time, for $26 its a low risk move but dont want to disassemble the pump cage twice if these are junk

I think you may want to follow the "if it ain't broke don't fix it" method on this.

17,000 miles on my 2012 and no fuel pump issue. A friend of mine has 55,000 miles on her WRX with no issues. As long as it works I would leave it alone. Normally the do give you indications that they are about ready to die such as no starts when hot. If you want you could always buy the pump and carry it with you but even that has some drawbacks.

Im at 15.000miles on my 2008 model (registered a few years later tho)

Bike worked no problem, parked it for 3 weeks (ok in the sun...), no go :-(
Diagnosis done for the fuel pump issue:

- Hear a definitive click from the relay when turning the key on, no noise coming out of the fuel pump
- Engine otherwise cranks just fine (but won't fire, no fuel smell)
- Battery good, reading 12.5v at the connector to the fuel pump (battery side)
- Plugging 13v external power supply to the fuel pump connector (tank side), no noise coming out of the fuel pump
- Reading 1.09k Ohm resistance between the leads of the fuel pump connector (tank side)

Anything else I should check before purchasing a replacement pump? I'd hate to be spending that much for another problem!
Thank you.

The fact that you cannot hear the pump priming is a strong indication that the fuel pump is dead; all the other numbers you list look good.

When you hint at the expense involved, do you mean that you plan on buying an OEM unit? If you look at a few posts up, a number of us are reporting good results with cheap replacement pumps after several years and thousands of miles of use.

@johnkol thank you, I am planning on purchasing an OEM unit to get the bike running -- I read that the part number 3D7-13907-10-00 might be a fix on the often failing 00-00 OEM.
Then once the bike is back functional I will try to fix the old unit with aftermarkets components as suggested.

My issues are similar, I suspect the fuel pump...

I've owned my 2008 WRx since 2012, with 2500 miles, and now it has close to 19k. I don't know what the previous owners did to it. I never had a single mechanical problem with the bike, it's been flawless. Stock tank.

Riding home from work the other day, the fuel light came on (as expected, around 80 mi). This is after riding 20 mi to work, and about 15 mi on the way home. it was about 65 F out. Shortly thereafter it started cutting out, like when you run out of fuel. It would catch and go a bit further, then cut out again. Finally quit altogether. I rolled to the side of the road. Turned key off. Checked fuel, there was still plenty sloshing around down there, so it wasn't dry. Tried to restart, but the starter wouldn't even turn over (?) which threw me off. A good Samaritan in a pickup stopped and offered to help. We talked for 2 or 3 minutes, then I tried again and it fired right up. I rode for another 2 to 3 miles, and it started happening again. I pulled over and shut down for 3 or 4 minutes, then started it up again. Luckily it was only a mile until I got back to my house.

Seems like it could be consistent with the fuel pump overheating (since fuel level was low, and it worked after 'cooling down' for a few minutes). Guess I'll replace it and see what happens.

- Ordered the KEMSO pump from eBay for $26, hope it works.

Also, unrelated, when I got home I noticed oil running down both lower forks. Guess both fork seals decided it was time to quit. Never noticed any leakage before, and I am pretty good at looking the bike over before riding.

dmmcd wrote:

Riding home from work the other day, the fuel light came on (as expected, around 80 mi). This is after riding 20 mi to work, and about 15 mi on the way home. it was about 65 F out. Shortly thereafter it started cutting out, like when you run out of fuel. It would catch and go a bit further, then cut out again. Finally quit altogether. I rolled to the side of the road. Turned key off. Checked fuel, there was still plenty sloshing around down there, so it wasn't dry. Tried to restart, but the starter wouldn't even turn over (?) which threw me off. A good Samaritan in a pickup stopped and offered to help. We talked for 2 or 3 minutes, then I tried again and it fired right up. I rode for another 2 to 3 miles, and it started happening again. I pulled over and shut down for 3 or 4 minutes, then started it up again. Luckily it was only a mile until I got back to my house.

These symptoms are the signature of fuel pump failures, although it is unusual for the pump to overheat when the ambient temperatures are that low; the starter not turning over is obviously not related.

Let us know if the Kemso solves the problem.

Off topic, but for fork seals get the SKF; they're pricey, but they're worth it.

johnkol wrote:

These symptoms are the signature of fuel pump failures, although it is unusual for the pump to overheat when the ambient temperatures are that low; the starter not turning over is obviously not related.

Let us know if the Kemso solves the problem.

Off topic, but for fork seals get the SKF; they're pricey, but they're worth it.

Yeah, I wasn't really paying too much attention, could have had it in gear or something, but no other electrical problems.

I saw the SKF kit on eBay with fork seal and dust seal for $80, compared to AllBalls or other no-name for like $25 or less. But consensus seems to be the SKF is superior. Plus they are a local company to me, so I like to support that when I can.

Last Sunday my WRR died in a remote rough dirt road; I could hear that the fuel pump was not priming, but I could not locate the failure point. All other electrical components were functioning fine, fuses were good, and I could hear the fuel pump relay clicking. Either there was something wrong with the wiring downstream of the fuel relay, or the Kemso pump had finally failed. And this was definitely not the well known pump overheating problem: even after the bike had cooled down, the pump wouldn't prime.

Bike had to hitch a ride on the back of a truck, and once I got home I started troubleshooting. Checked the wire behind the radiator (a known point of failure that can manifest as pump not priming) but the connection was firm. Checked the Run switch, but it too showed no signs of wear. I finally connected the battery directly to the fuel pump wire leads, and the pump remained silent. I took the pump assembly out and this is what I saw:



The positive wire lead had worked itself off. These are secure connectors, with a tab that locks onto the hole in the pump lead, but somehow this locking tab had either flattened or sheared (from vibrations?), and the lead was hanging on to the connector through friction alone; with enough vibrations, and after hundreds of miles of hard bouncing on rough dirt roads, the connector had worked itself off the lead.

I haven't read any reports of such a failure before, but if you have to change your pump, make sure that the locking tab on the wire lead is intact; using safety wire wouldn't be a bad idea. I actually ended up soldering the lead to the connector just to be extra safe.

One more issue I discovered: I have the IMS 4.7 tank, and the fuel suction tube is attached to the fuel pump assembly with zip ties. When I installed the pump four years ago, I had tightened the zip ties securely, but now I found them to be loose: apparently they expand from immersion in gasoline, and the suction tube was no longer sitting deep in the well, but about half an inch above it. I tightened them again, and hopefully they will not expand anymore.

I guess I join the club. Only thing is, I already replaced the OEM fuel pump with a Kemso last night. I have an 08 WRR with ~6900 miles. It was having the classic fuel pump problem in hot weather so I finally got around to replacing it. Took me all afternoon and night since I'm new to bikes, but I followed the guides online to the letter. The bike actually started up and ran for about 5 minutes last night, and I was so happy. But now this morning I go and try and turn it on, and it starts, but only for a few seconds before cutting off. Now this is all I get; streamable /3b11zi (I guess I can't post links but I'm not a spammer, I actually need help)

I don't know if I could have missed something or got a faulty pump (again...) but I am feeling pretty defeated by this thing. I thought these bikes were bullet proof

waterfowl wrote:

The bike actually started up and ran for about 5 minutes last night, and I was so happy. But now this morning I go and try and turn it on, and it starts, but only for a few seconds before cutting off.

Stock or aftermarket tank?

When it idles for a few seconds, is the idle normal, or does it sound rough?

'08 with over 11k and I'm getting the dreaded symptoms. Kemso ordered. Thanks for the paper trail, gang.

I got my pump replaced last week, but waited for a new O-ring to arrive while I had everything apart - the 14-year-old one was stiff and left some residue on removal. Got it in the mail yesterday and buttoned everything up.

On first ride around the block last night, and then 25 mile commute this morning, I have two impressions. First, the Kemso is a fair bit quieter on priming than the OG pump was. Wow. Wasn't' sure it was working at first. Second, though, it feels like some of the throttle 'snappieness'/'snatchyness' is gone. I can't tell by my butt-dyno if it's also pulling less hard, or if all of it is just in my head after only 2 rides, but anyone else note the same?

I don't recall an audible difference between the OEM pump and the Kemso, but maybe Kemso has improved their pumps in the intervening years.

The reduction in performance has no logical basis: all the pump has to do is maintain a steady pressure of 36 psi; any pump that can accomplish that would be indistinguishable from any other pump that can meet the same specs. If it cannot maintain the required pressure, then you would immediately experience cut offs, which is something I experienced when the pressure regulator developed problems.

johnkol wrote:

The reduction in performance has no logical basis: all the pump has to do is maintain a steady pressure of 36 psi;

After riding today without giving it a thought until just now, I have to conclude I was probably just up in my own head about the performance on Friday.

Thought that I would add some useful info about the fuel pump and possible alternatives. I broke off the outlet nozzle when the tank dropped !

Yamaha use the same fuel pump body on other models of bike, they tend to have a fuel sender attached instead of the low level sensor. The sender can be unclipped and the level sensor clipped in place, in my case I had to secure it in place with a 3.5mm Stainless steel screw. The other thing to do is to rotate the output nozzle of the pump. this can be done easily by using a junior hacksaw to cut the locating tabs off and allowing it to be rotated freely to any position.

The pump I bought from eBay with 1800miles on it was from a MT-03. £39 ! (47$). A WR125 pump is also the same.
time to do the little modification was 20 minutes