Bog/Power Loss Issue

New to the forum, just bought a 10' WR250R and pretty much covered a lot of mods right out of the box. I had an issue today while riding it where it would cut power or almost bog during acceleration and harder riding. This was on the street and seemed to be happening around 45-50 MPH range while giving heavy throttle. I had a similar thing hit me last week when I was riding a set of whoops pretty hard and all of a sudden it cut power very briefly and I almost went over the bars. At the time, the low fuel light was on and I pretty much chalked that one up to low fuel and a momentary starve. Now they seem related. Hoping someone here can point me in the right direction.

My mods relevant to this issue are are FMF Q4, FMF Megabbomb, FMF Programmer, AIS Delete, Ultimate Airbox Mod, Twin Air Filter. FMF Settings are 3.5,4.5, 1.5, 8,4,4.5

If anyone has any suggestions on what to look at I would be very much appreciative!

Forum is great by the way! Excited to get in on the action here and contribute as I can. I know I have gained a lot of info ever since I started looking at these bikes. Good group for sure!

Okay - so just to get a few things off the table here.

Not implying anything with this question - just trying to cover the first thought things that pop into my mind.

1) You 100% sure you're not hitting rev limiter in those situations?

2) Have you run through a full tank and refilled with high test gas since this happened? From a different gas station?

3) Have you checked to make sure all your connections are complete regarding the AIS removal and other mods? No open vacuum lines or anything?

4) Can you reproduce the "bog" at will? Can you make it happen again? Or was it a one & done kinda thing?

No worries on not wanting to imply I may just be clueless! I think sometimes I may be!

In all seriousness though, let me answer your valid questions...

1) About 99.9% sure it's not the rev limiter. I have hit the limiter on this bike and others. From my experience a rev limiter type of power loss is more of a on/off/on/off/on/off which fits the saying 'bouncing off the limiter'. This power loss is more a complete off cycle until I release the throttle and get the rpm's down. I can see where you'd be concerned that the rev limiter is the issue but I am pretty sure thats not it. I know the revs are up there when it happens, just not that far up there.

2) Yes, I have actually had two tanks through it, both high test and they were from different stations.

3) No, I have not checked connections but will go through every mod I did and double check install and report back.

4) The bog happened last night 3 times within a 5-6 mile ride and then I put it up, had family stuff that needed tending to so I posted my concerns from there. I am pretty sure I can get it out today and duplicate it, though the weather is not completely cooperating with that thought at the moment!

From my experience I would say it would feel either vacuum related, air flow related or fuel related. I question the FMF Programmer but I chose settings that seem to be very common on here so I was kind of thinking that was not it as I have not heard of my issues when I searched for similar symptoms.

I may take it out when the weather breaks and ride as is, see if I can duplicate. If so, reset the FMF Programmer to factory settings and see if it goes away. I will report back on the test ride and let you know.

Thanks very much for trying to help me out Motokid!

Thanks for understanding the "no implications" thing. Some guys get really bent if they think somebody is asking "stupid" questions.

It's all about trying to get some more information. Not about insulting anyone or their ability to trouble shoot.

So you have, and can recreate the issues????

Is it only in one gear? At only one speed/rev range?

Or, is it in every gear at a specific rev range?

Oh yeah, I know about the 'sensitive' motor heads that know everything yet they coming into forums asking for help only to get bent when guys ask the obvious. I do know how to troubleshoot many things, the one thing in common with all of them is the simple process of elimination. Putting minds together to brain storm the often obvious is what makes the forums so nice. I can't tell you how many times it's someone pointing out the obvious that was actually the issue. We often get sidetracked on what we think it is and sometimes it takes a fresh mind and approach to see it from another angle. As you'll come see I am a pretty easy going cat thats pretty hard to offend! Thanks for your conscientious approach though!

Recreate, not yet. This only surfaced on a quick trip to the store last night. It did happen three times so I am thinking it'll happen again today if I ride it in the same manner. As for which gear it happens in? Good question and I will make it a point to have that answer after I am able to get it out again. At this point, I would say the three instances were at the same rev range though. With no tach, I can only say it was near the top but not at the top. In hindsight, I do not think it was gear specific though. I will definitely pay close attention to all parameters of the problem on the next get out.

Stay tuned for the findings! Thanks again Motokid!

No problem. I enjoy the process of trying to figure out what's wrong. Especially when it's not my motorcycle.


If the bog happens in every gear I'd be tempted to question the FmF programmer.

That's a relatively easy check. Disconnect it completely and see what happens.

If the bogging issues are only in one specific gear I'm totally stumped.

motokid wrote:

No problem. I enjoy the process of trying to figure out what's wrong. Especially when it's not my motorcycle.

Ha! I hear that!

I may even try to ride with my GoPro camera running and may post up some video so you and others can see/hear what it's doing.

Anybody have any advice or suggestions for this issue and MXZDrew????

fuel pump maybe, pinched fuel line?

no idea, good luck though keep us posted

spacecadet wrote:

fuel pump maybe, pinched fuel line?

no idea, good luck though keep us posted

It's a 2010 model - so the likelihood it's fuel pump related is pretty small.

Your fmf settings should be fine for those mods.
Almost what I am running with the only real difference I have a powercore4 and powerbomb

Check your plug gap, if fmf controller plugs on engine are snapped all the way, fmf controller battery ground connection, connection on bottom of tank in no particular order.

If it still does it I would check other connections like the kickstand switch, kill switch, tip over switch, connections to coil.

Being that it's doing it under acceleration... have you tried bumping setting 2 up to 5?

also you could go back to stock see if it still happens, then add mods one at a time to try to see where it happens?

Well thanks for all the other tips everyone. So far the problem has not resurfaced! I guess thats good and bad, I don't want to chase the issue down but I hate it when something was clearly wrong and then just goes away! Got about 20 miles in on the trail today and never noticed anything out there except it stalled a couple times when coming to a stop. No bigggie I suppose.

My only issue now is another topic... after all these mods the bike is still not up to my standards as a woods bike. I get the trade off's with a dual sport but I thought I could mod the thing and make it favor dirt and sacrifice on the street. While all I have done is a HUGE improvement, it is still too weak at the bottom of 2nd gear for punching out of corners as I am used to. That weak second gear also seems to make sand more challenging. As soon as I spin up second the bike charges through sand. I am hitting 30 MPH in second out there and thats bordering on the edge for the trails I am on. I think I will be ordering up a 50T rear, maybe more and run it with the 13 up front, then I can switch to my 12 for really tight trails. I just want more power down low. Hopefully this can get me there. I will post up my results with that in the sprocket group as I get it done.

Will report back here if and when the bog returns...

You all are a great help, thanks!!

Yes, if you want to make it more like a woods bike, you have to get rid of the street gearing.
A 250cc woods bike won't be doing 30mph in second gear, will it?
That's what a street bike does. ;)

YZEtc wrote:

Yes, if you want to make it more like a woods bike, you have to get rid of the street gearing.
A 250cc woods bike won't be doing 30mph in second gear, will it?
That's what a street bike does. ;)

Sometimes the obvious eludes me! Nice to see others agree I am approaching it right though...

Wow I logged into the system this evening for the same problem. I have a 2010 wrr and recently installed the Flatland racing skid plate on it. Because I live in California I had to remove the charcoal canister. I followed the instructions on this sight and capped the throttle body connection to the charcoal canister and rerouted the gas vent line. I took it out today and the bike seems to be lacking / bogging in power and the engine has a top end noise (sorta/kinda loud valve noise). I live and ride in the mountains above 5,000ft. Does this sound like a vacuum problem or a air starvation problem (does it neede the vacuum lines to breath better)? I need to get the bike ready for next weekend as we got a 128 mile dirt ride planned.

By the way up to this point the bike has been perfect.
Thanks

Low or bad fuel ?
Cold engine?

I get a bit of bogging when I have both or 1 of these, no bothers otherwise

RidgeRunner wrote:

Wow I logged into the system this evening for the same problem. I have a 2010 wrr and recently installed the Flatland racing skid plate on it. Because I live in California I had to remove the charcoal canister. I followed the instructions on this sight and capped the throttle body connection to the charcoal canister and rerouted the gas vent line. I took it out today and the bike seems to be lacking / bogging in power and the engine has a top end noise (sorta/kinda loud valve noise). I live and ride in the mountains above 5,000ft. Does this sound like a vacuum problem or a air starvation problem (does it neede the vacuum lines to breath better)? I need to get the bike ready for next weekend as we got a 128 mile dirt ride planned.

By the way up to this point the bike has been perfect.
Thanks

Take the skid plate off, and reinstall the charcoal canister exactly like Yamaha had it. Then see if your problem goes away.

That should at least isolate what your potential issue might be.

RidgeRunner wrote:

Wow I logged into the system this evening for the same problem. I have a 2010 wrr and recently installed the Flatland racing skid plate on it. Because I live in California I had to remove the charcoal canister. I followed the instructions on this sight and capped the throttle body connection to the charcoal canister and rerouted the gas vent line. I took it out today and the bike seems to be lacking / bogging in power and the engine has a top end noise (sorta/kinda loud valve noise). I live and ride in the mountains above 5,000ft. Does this sound like a vacuum problem or a air starvation problem (does it neede the vacuum lines to breath better)? I need to get the bike ready for next weekend as we got a 128 mile dirt ride planned.

By the way up to this point the bike has been perfect.
Thanks

I think Motokid has the right approach for your issue, definitely see if the problem goes away by reinstalling your canister. I don't think my bike ever had that canister, must be a CA thing I assume. My issue was a little different than yours as the bike ran solid 98% percent of that ride. The bogs were more 'incidents' than a constant issue. With mine, one of them almost put me over the bars as I was in heavy whoops and then the power cut out. Imagine hitting your kill switch when you are already committed into a set! Yeah, I did not like it at all!

Keep the thread updated though with what you found with yours and best of luck RidgeRunner!

Yesterday it rained so I took that opportunity to reinstall the charcoal canister. Today it is bright and sunny so I will redo Saturday's run and see what happens.
If replacing the charcola canister returns the bike to normal does anyone have ideas of how to install a flatland racing skid plate on California bike?
Thanks for all your help.

Wishing you Blue Skies
and Green Mountains