Lose power while cruising

OK guys help me diagnose my issue.

2008 WRR, FMF Q4, FMF PP, all the crap removed. On last couple rides I have taken the bike will suddenley lose power while cruising, like its not getting fuel, if I roll off the throttle for just a second and get back on it the bike is fine, if I try to give more throttle the bike starts sputtering. My guess was fuel pump but its weird that it only does it while cruising. Any guesses?

My bike (2008 WR-250X) will do that once in a while, too.
In fact, it did it once shortly after I bought it (used, with 3,911 miles on it) when it was still in stock condition.

My description of the problem is similar to yours:
Out of the blue while rolling on the throttle, the bike will skip and misfire, as if it suddenly ran into a rev limiter at half-way to redline.
Rolling off the throttle and back on cures it, and it typically doesn't happen again for the rest of the day.

I've recently changed to a brand-new fuel pump as a preventive measure, and it still does it once in a while.
Not often enough to where it's a major problem, but typically, if I ride the bike for a couple hours, it may do it once during that couple hours ride.

There have also been numerous rides where it didn't do it at all.
In fact, more rides where it didn't as opposed to rides where it did.

My guess is that it's not fuel pump-related, and maybe even a glitch with the fueling.
The possible glitch is just a guess, so don't carve that comment of mine in stone, but, a new fuel pump and the mods I've done (typical exhaust, FMF Power Programmer, AIS removal, airbox flapper removal, geared down) did not make a difference.
Luckily, as stated, it's a once-in-a-while thing.

On the 2008 WR-250R I rode last year, I can't remember it happening with that bike, and I rode it for 7,500 miles.
So, maybe it's a some-do-it-and-some-don't thing.

Yeah I'd guess fuel pump as well. Also check you air cleaner before you go run out and get a pump.
The reason it bags out is because the pump is weak, and it loses pressure and can't keep up with the fuel demand when you throttle it. You could probably coast around all day with minimal throttle because the demand isn't there. When it heats up tho, eventually it will pack it in and totally die.

YZEtc wrote:

I've recently changed to a brand-new fuel pump as a preventive measure, and it still does it once in a while.

Wait...what????

New fuel pump and you still have the same kind of issues? Just not as often????

Shewolf, the problem is mine does it only when cruising not during hard acceleration, I would think hard accel would be tougher on the pump.

motokid wrote:

YZEtc wrote:

I've recently changed to a brand-new fuel pump as a preventive measure, and it still does it once in a while.

Wait...what????

New fuel pump and you still have the same kind of issues? Just not as often????

The new fuel pump seems not to have changed anything in regards to this.
When the problem occurs, it does it without warning and it is not according to any kind of predictable pattern or conditions that I can see at the moment.

I decided to change the pump so that it wouldn't quit and leave me there waiting for things to cool down.
That fear has probably been erased by the new pump.

*crosses fingers* :)

On the other hand, while I expect the new pump to not up and quit when things get hot, the seemingly unpredictable power loss/sputtering can still rear it's head at any given moment.
Thank God it does it only twice in a blue moon, and there have been more rides where it didn't happen than those where it did.
I can live with it as-is because it's fairly rare in it's occurances, but, if I knew how to eliminate it (assuming there was actually something I could do), I would.

At least the bike runs excellently, and a mere roll-off and roll-on of the throttle rids it.

Almost sounds like a vapor-lock condition. ~ shrug ~

X-Racer wrote:

Almost sounds like a vapor-lock condition. ~ shrug ~

That is what I was wondering too (mine does something similar). Is the gas cap the only vent for the stock tank?

Maybe yamaha had some problems with the TPS on the wr250, i know they had it on the xt660 models.

The problem will appear almost like U running out of fuel, but if U adjust the throttle a bit its fine.

So if you measure your TPS with a multimeter U should have a nice curve all the way and no crazy figures in the middle.

I know its a longshot but anaway.

Yamaha had problems with the ECUs on the 07 YZFs as well that had a very similar symptom.

You'd get the bike into the 4-5K RPM region and the power went completely flat. ...but if you powered through it you'd never see it.

They eventually admitted there was a problem, but no recall. Mine was replaced free of charge (of course it was on Y.E.S.).

Mr. Cave: That'd be a great "How to" for this section.

Now i HAVE to dig more in this matter because today my bike went bananas a couple of times......

Only when cruising, and when you keep a constant speed.

From out of the blue the bikes cut of sometimes just for a "blink" but sometimes really dying and then fires up again... really annoying especially if you are taking a corner in high speed and need the power to turn properly.

1. Is it possible to disconnect the tilt killswitch somehow?? (just to make sure it is not that wich is messing things up)
2. Disconnect killswitch for stand??
3. Check/ measure TPS, factory problem?
4. IS there really maybe a factory problem with the ECU???
5. Can it be some cable or switch problem to/ from key or the red killswitch bad connection etc.....?

"Only when cruising, and when you keep a constant speed."

Same for me....
09 WRR FMF P4, FMF PP,FMF MB all the crap removed

I'll keep an eye on this post

I have now measured my TPS.
There are 3 pins (call them 1,2,3 seen from left if you stand on that side of the bike)

Between 1 and 3 i had 2,24 ohm (no throttle), and 0,59 ohm at full throttle.

Between 2 and 3 i had 0,39 ohm (no throttle), and 2,03 ohm at full throttle.

But i dont have the repair manual for this bike so i dont know if these figures are right.

I then sprayed that connection with 5-56 lubricant to get a good connection.

I also took apart the red killswitch on the bar (its a silly construction and im not surpriced at all if that can cause some trouble). But i just sprayed it on the inside for connection.
Then i removed the sidestand switch and welded the two wires together to be sure it connects proparly. sprayed this connection to...
I removed contact to ecu and sprayed it and also the tilt switch got sprayed.

After that i went to the gas station and filled her up with 98oct and did a test run for about 30km.
Not a singel tendency to die......not even the smallest.

Yesterday it died on me atleast 2-3 times in about a 30km trip.

So now im not sure if it is just temporary or if the spray did some miracle cure or what...

I don't have time this week to do anything because I'm going up north this weekend. Just got my SpeedoDRD today so I have to hook that up next week. I think I'm going to follow mr-cave's lead and do the same thing he did. I'll post next week and let you know if it helped.

Hey guys I could be wrong but if ur all having this cut off problem at around 60mph cruising and u have the fmf PP it could be the settings. I also had this problem. So I call the maker of it and he gave me some settings and ever since I used them the bike never cut out again. Try 3, 2.5, 1, 8, 3, 4

Matt.

Mine's been doing this too since I had to change fuel pumps to another '08's after dropping my tank. I'm hoping to mess with my programmer settings tonight to help make it go away. No clue if its the pump or the programmer since I dropped the tank while installing the programmer...

I did a longer trip today. About 100km trip.

It died on me 3-4 times. So the things i did was not the sollution but we can count out sidestand switch anaway.

But i tried someting else after i stopped for gas. I adjusted the CO1 figures from 5 to 10 and the jerkiness that you can feel when you turn on/ off throttle felt a lot smoother.
I guess the FMF PP adjusts the fuel little later than the ECU?

But still...it dies sometimes.

Anyone have the repair manual and can check the values on the TPS?

Did the later models have this problem also? 2009 and up?
And if they dont. What have they changed? (TPS, crankcase sensor, ignition coil, ECU etc etc.....)

mr-cave wrote:

I did a longer trip today. About 100km trip.

Did the later models have this problem also? 2009 and up?
And if they dont. What have they changed? (TPS, crankcase sensor, ignition coil, ECU etc etc.....)

Mine is doing it and it's a 2009 WR250R.... I think I'll start messing with the FMF PP on Monday. I think I'll do like mattnadz and call them and ask about settings because I'm also running the MegaBomb with the Powercore 4.

TEL (310) 631-4363
8am to 5:30pm PST M-F

It only started doing that to me when I threw on the fmf PP. I put in those recommended settings from the maker of it and its never happened again. Its been 5months and 5000kms since and no more issues.

mattnadz wrote:

It only started doing that to me when I threw on the fmf PP. I put in those recommended settings from the maker of it and its never happened again. Its been 5months and 5000kms since and no more issues.

Thanks mattnadz... I bought wifarmboy's bike and he couldn't remember what he had in it. I'll start working on this next week and post back with the results.

I was running values similar to what was recommended above (2 5.5 1.5 8 4 4), changed back to the settings I used before ( 3 5 1 8 .5 .5) and much of the jerkiness is gone. My CO mode was adjusted from -2 to +2 as well, but that has not changed since I installed the PP.

skierd wrote:

My CO mode was adjusted from -2 to +2 as well, but that has not changed since I installed the PP.

New to working on bikes.... CO mode?

Well called FMF and they said to set it up to
3/4/.5/8/4/4.5

I set it at that and set up the SpeedoDRD but it looks like rain most of the week... I'll post back and let you know how it goes!

Well I got my new tires on the bike yesterday and drove around for about and hour and had a blast. With the bike set with the settings FMF gave me (3/4/.5/8/4/4.5) I didn't have a problem with stalling at all:) I mean no cut out or stutering at all.... that was with running in way to high a gear and high RPMs. The bike just ran like butter

mattnadz looks like you were right for my set up and it was the PP. Thanks for the help guys.

Mines been having the issue, though not as frequently, with the revised programmer and CO mode settings. I just changed the plug and coil in hopes of fixing it as I don't think my problem is fuel related. The old coil has 28k on it and looked pretty beat, rusty and didn't want to really seat on the spark plug during the last plug change nor come off this time, but the new coil dropped right in and connected much more cleanly. I didn't have a new plug, so I changed back to the plug that was put in during my valve service 3k ago (2k on the plug) as I know it was good vs. the plug I've been running that was my spare rattling around in my saddle bags for ~8k miles. I should know on my rides to and from work tonight if its fixed...