Full Throttle Bog (75% throttle sweet spot?)

Hello guys, first post here. I have recently gotten myself a 2011 Wr250R and i will list the mods i have done so far below. But my current problem is that in higher rpm's in high gears like 5th and 6th when i go to floor it (and hit top speed per say). The bike beginds to bog at 100% throttle turn. But if i roll off it slightly to say 75%, it feels like a sweet spot and will continue increasing speed. I have tried different airbox modifications and also tried messing with the CO settings as well as trying many FMF EFI Settings that you guys have posted on the forums. But nothing has really helped. Anyone else encounter this?

MODS:
FMF Power Bomb
FMF Power Core 4
FMF EFI Tuner (Tried every and all settings)
Top of airbox removed, Side door removed
AIS Removed, Flapper Deleted
13/43 Sprockets
17" Supermoto Wheels and tires
Clean filter, fresh oil, brand new plug. 93 octane.

The guy i bought the bike from said the bike was "Tuned" so i figured it has a fmf efi, but when i asked he said no efi controller. He said the ecu was tuned, It was not driving that great so i purchased and installed a fmf efi controller. is it possible to tune the oem ecu? and can it be what is affecting my bike? i live in tampa FL so im at sea level.

Hope You guys have something for me! - Steven

The Main setting i have been liking on the bike for the efi tuner are
4,6,8,8,6,4

I have tried adjusting more or less fueling across the board to see if it was running lean or rich. But the bike really likes the first 3 settings being high. It rippes during the acceleration period but seems like its too lean up top at full throttle. Wish i could put the settings on the controller higher to maybe 10 for full throttle

I also tried adjusting the throttle cable to see if it was being pulled too far some how when at 100% throttle but that did not help, only added play and still caused bogging. I may remove my throttle body today and clean it since the owner previous loved to oil his air filter heavily. Maybe there is some gunk in there. Or maybe there is enough carbon buildup on the piston to cause problems when full throttle fueling is happening. The bike has 8,000 miles and has always been fed premium.

My bike is stock and it does the same thing. If I give it full throttle at medium rpm's it will bog. I just downshift once or twice to get'r'screamin'.

Mines a little different. It bogs more and more when rpms are increasing. I notice it a lot in 5th and 6th gear due to the gears being longer. It also keeps me from reaching top speed due to the fact that I can only 75% throttle it in 6th gear. If I could smoothly full throttle the bike it would reach top speed and eventually the rev limiter. Very strange and annoying when trying to pass cars on roads with a high speed limit like a highway.

You might try putting the door back on the air box or at least sealing it off with some tape/cardboard if you don't have the door.

Just to test, since this sounds related to me

I'll try putting the door on today. It could be running lean. Does anyone know if CO settings adjustments change fueling for WOT? Or is it just for idle?

Can you bounce off rev limiter in gears 1-4 ???

What happens when you whack open the throttle in second and third gear?

sramsland wrote:

The guy i bought the bike from said the bike was "Tuned" so i figured it has a fmf efi, but when i asked he said no efi controller. He said the ecu was tuned, It was not driving that great so i purchased and installed a fmf efi controller. is it possible to tune the oem ecu?

This has me a little concerned. I've not heard of such a procedure before.

Did you ask who "tuned" it?
Or what they did?

I would try to get some more info on that.

I've never heard anyone say they could reflash the original computer

I can bounce off the limiter in gears 1-4, if I whack full throttle the bike does really well now that the fmf tuner is installed. Does not big until high rpm in 5th or 6th. Then I roll off the gas to about 75% throttle and I begins to accelerate again. But I does not reach the top of the rpm band because once I roll back to 100% it bogs. Does it pretty immediate too. And since the only thing that changes from 75% to 100% is the throttle body and fueling I'm suspecting it's either running too lean, due to the body being completely open. Or rich, but I have tried all from 0.5 to 8 for the red mode on the fmf tuner. And the bike feels most powerful at 8. I'm thinking it's running lean and the stock injectors cannot output anymore duty.

Stupid iPhone. "I" being "it".

I also installed the airbox door and could not feel a difference. I'm using a oem looking foam filter on the intake btw.

sramsland wrote:

I'm thinking it's running lean and the stock injectors cannot output anymore duty.

I seriously doubt the injector is fully saturated, I'm running 306cc's & cams with the stock injector with no issues.
With your stock engine, you shouldn't need a tuner for WFO. I suspect you have a fuel supply issue with your pump, regulator or restriction in your fuel line (kinked?)

That is possible. I will look online for a diagram of the vacuum and fuel lines. I did stumble across something on my ride to work today, I used duct tape to close off most of the top of my airbox to allow only close to stock amount of air into the airbox and I used the settings 3,3,3,8,8,8 on the tuner. And it ran better. Then I removed the tape and it bogged just as before...So it seems that the bike is running lean, even if my settings are maxed out across the board at 8,8,8,8,8,8...

Now i have a question, have any of you guys ever heard of anyone else running lean due to too much intake modification? i see some guys and their airbox mods and i would say they have even more airflow than i, but they dont post any negative problems coming from it.

If you're lean at full throttle in 5th and 6th gears - why are you not lean at full throttle in 2-4th gears?

From the point of view of the air/fuel ratio, what gear you're in shouldn't matter.

I've NEVER heard of anyone running so lean their X/R bogs at WFO throttle.

The flow rate of air being used in 5th and 6th is greater than 2nd or 3rd because of engine load. I have a turbo'd car and used to get intake collapse in high gear due to more air being used per second in my final gears. So i was thinking it was kinda the same thing. But the opposite lol.

hmm sounds very intriguing have you
Checked the tps reading?
Have you checked for air leaks?
A kinked fuel line sounds plausible but would be choppy in my experience.

thats all I can think of but it does sound very similar to a old ratty 2 stroke moped i worked on once... the parts of the air box were missing and i essentially had to make one from from scratch, and had to keep choking up the design until i got to a point where the little guy would accept full throttle

I'll go out and check the tps now. Didn't know you could do that on bikes. These WRs are very smart little machines. I'll also check the fuel lines. I have removed the tank so I could have slightly kinked one.

With the bike off it reads 16, than full throttle is 96. Is it off?

I found this!

That hose was folded 90 degrees horizontal to vertical. I removed it and straightened it out (needs replacing because it's creased). But I'll get back to you guys if that was the culprit.

It was DEFINITELY the hose. Have never felt this bike run so good! My god the things rips! I could only do 80 mph (speedometer not fixed with the 17's) just did 93 and had to let off! Thanks for the input and helping me figure the problem out guys. I don't even know how the bike got any fuel with the way the hose was completely folded.

Great to hear she is fixed. Poor little girl was thristy...Now she can drink.  

Now, go enjoy that bike !!!!