Severe stumbling at altitude

I have had stumbling problems on my 07 since I got it, I see that other people have had the same problem. Mine seems to get worse with altitude, and that doesn't make sense to me. Yesterday, I went for a ride, noticed the hesitation getting worse as I went higher up a mountain, when I got to about 3500 feet or so it got so bad I thought the bike was going to die. When I started back down, the hesitation became less and less. I haven't had the throttle body sync done yet. This makes no sense to me since the bike is fuel injected. I don't think it was just coincedence.

Any thoughts would be greatly appreciated, I am getting very frustrated.

Greg

Greg, did you try using the "search" function? A quick search using the word "stumble" yielded this a quick search & I am also not sure if this will help but try the search function.

Also, as a f' new guy you probably don't know this... but this post should've been posted under the "technical" section. The admins will probably swoop down & whisk it to that spot... so wave butt bye!!!

Congrats on your new bike. Hope you solve your problem.

this is odd to me. I have taken my bike to 14,000 feet in Colorado and never had a hiccup

greg97224 said:

I have had stumbling problems on my 07 since I got it, I see that other people have had the same problem. Mine seems to get worse with altitude, and that doesn't make sense to me. Yesterday, I went for a ride, noticed the hesitation getting worse as I went higher up a mountain, when I got to about 3500 feet or so it got so bad I thought the bike was going to die. When I started back down, the hesitation became less and less. I haven't had the throttle body sync done yet. This makes no sense to me since the bike is fuel injected. I don't think it was just coincedence. Any thoughts would be greatly appreciated, I am getting very frustrated.

Greg

Click to expand...

My '07 does the same thing with increasing altitude. At the 600 mile service the Tech increased the CO2 settings by 2 units and this seems to help. However it is not as good as my '03 with 45,000 miles. I did find if I shifted down 1 gear to get the RPM's higher this helped as well.

Whoever was quick to pull the "do a search" trigger missed the key issue...problems at altitude on a 2007.

As an 07 owner who just experienced a near disabled bike at altitude I would say this thread most certainly has reason NOT to be moved. I was certain it was bad fuel. Later checked for possible bad altitude sensor but it was ok. FWIW, I have not had stumble/hesitation issues. FWIW, I've done 2 TBS in 8k miles.

To the original author, what was the elevation gain/loss in which you experienced this issue??

AGirl

stumblin at altitude? somethin wrong wid sumbuddy's 'puter chip?

So obvious.

The 06 onwards has a stumble 'built in'. I had a season of to-ing and fro-ing with Yamaha which led to a complete refund. In retrospect I should have stayed with the bike and got it put right by an outside source. I now run an 05.

Back to topic. The reason that they stumble is because they are set so lean to cope with the emission laws. For the uninitiated, lean means less petrol in the mixture is going into the engine than should be. (Mixture of petrol & air). Now when you go to altitude the air is thinner as well, so like an athlete the engine struggles for breath. As it is already asthmatic it stars to falter. The computer should compensate for this. Obviously its not doing that.

Check this out:My 06 story (changed my name since this)

Good luck.

My 05 lives at 5500 and up. No stumble. 'Course I run 85 or 86 octane.

I've had a "stumble" at altitude but it was usually after too many beers. <_<

Seriously, my '07 lives here at 5000' and have never had a "stumble" with the engine. It sounds like your CPU is not compensating for altitude, maybe a sensor problem.

AZ

AGirl said:

Whoever was quick to pull the "do a search" trigger missed the key issue...problems at altitude on a 2007.
As an 07 owner who just experienced a near disabled bike at altitude I would say this thread most certainly has reason NOT to be moved. I was certain it was bad fuel. Later checked for possible bad altitude sensor but it was ok. FWIW, I have not had stumble/hesitation issues. FWIW, I've done 2 TBS in 8k miles.

To the original author, what was the elevation gain/loss in which you experienced this issue??

AGirl

Click to expand...

I am guessing the altitude was around 3 to 4000 feet.

OrangevaleFJR said:

this is odd to me. I have taken my bike to 14,000 feet in Colorado and never had a hiccup

Click to expand...

:blink: I'll second OrangevaleFJR's experience as I have had my '06 FJR over 12,095 feet @ Independance pass and five other passes over 10,000 and not one hiccup or burp, just a handful of power and acceleration whenever called upon, smooth and awesome!

Scott

Greg, I guess the similarity is that we both live in Oregon and both have 07's I hope Yamaha figures this out soon.

I have the exact same problem as you ...

Post 44 and 55 here:

https://www.fjrforum.com/forum//index.php?s...40&start=40

I live at nearly 5000' and recently went over the pass to Park City which is about 7800' (Parley's Summit) and it was smooth as silk. I try the easiest thing first and get some higher octane fuel from a different station.

I probably filled up at least 5 times at different stations throughout Oregon and CA over a 4-day 1350 mile trip last Sun-Tue ...everything from plus to super unleaded. Still surged. With my bike above 1000 ft. it's not matter of "if"it will do it, it's "when". Not fun being leaned over in a twisty half way thru the corner, loose all power then instantly get all power at once.

This must be mainly an 07 issue. I've run up some of the high points in NC/TN I would guess at least 4-5000ft and not had a prob on my 06.

feejer222 said:

So obvious.
The 06 onwards has a stumble 'built in'. I had a season of to-ing and fro-ing with Yamaha which led to a complete refund. In retrospect I should have stayed with the bike and got it put right by an outside source. I now run an 05.

Back to topic. The reason that they stumble is because they are set so lean to cope with the emission laws. For the uninitiated, lean means less petrol in the mixture is going into the engine than should be. (Mixture of petrol & air). Now when you go to altitude the air is thinner as well, so like an athlete the engine struggles for breath. As it is already asthmatic it stars to falter. The computer should compensate for this. Obviously its not doing that.

Check this out:My 06 story (changed my name since this)

Good luck.

Click to expand...

Actually if it was a lean fuel mixture issue it would get better with altitude. Same amount of fuel + less air = richer mixture. I live at seal level and ride my dirt bikes mostly between 4000 - 7000 feet. They're pretty lean at sea level (popping on decel, ect.) but fatten up nicely at alitiude. Unless they've put a MAF sensor on the 07's I would think the same logic would apply.

On further reflection I recall someone mentioning an altitude sensor. If an 07 indeed has an altitude sensor then a lean condition stumble could/would get worse with altitude. An easy fix might be to eliminate/bypass the altitude sensor. Don't know if it's possible though.

evil_henchman said:

feejer222 said:

So obvious.
The 06 onwards has a stumble 'built in'. I had a season of to-ing and fro-ing with Yamaha which led to a complete refund. In retrospect I should have stayed with the bike and got it put right by an outside source. I now run an 05.

Back to topic. The reason that they stumble is because they are set so lean to cope with the emission laws. For the uninitiated, lean means less petrol in the mixture is going into the engine than should be. (Mixture of petrol & air). Now when you go to altitude the air is thinner as well, so like an athlete the engine struggles for breath. As it is already asthmatic it stars to falter. The computer should compensate for this. Obviously its not doing that.

Check this out:My 06 story (changed my name since this)

Good luck.

Click to expand...

Actually if it was a lean fuel mixture issue it would get better with altitude. Same amount of fuel + less air = richer mixture. I live at seal level and ride my dirt bikes mostly between 4000 - 7000 feet. They're pretty lean at sea level (popping on decel, ect.) but fatten up nicely at alitiude. Unless they've put a MAF sensor on the 07's I would think the same logic would apply.

On further reflection I recall someone mentioning an altitude sensor. If an 07 indeed has an altitude sensor then a lean condition stumble could/would get worse with altitude. An easy fix might be to eliminate/bypass the altitude sensor. Don't know if it's possible though.

Click to expand...

Have any of you considered doing the barbarian jumper mod then increasing your CO settings? I did this to my 06 (had an 05 too) and it corrected the abrupt on/off throttle issue. I live at 6,200' elevation and regularly ride up our mountain out back (Sandias) to 10,400' and haven't experienced stumbling or surging. Hmmm.

My bike already had the barbarian mod and was set to +4 when it first happened. During the course of a 3 day trip I tried reverting to stock settings and +7 with no change. Still surged above 1000'. The abrupt on/off throttle is not a problem for me ...also have the G2 throttle tube. It is strictly the surging at altitude that's my problem.

kindofblue said:

Have any of you considered doing the barbarian jumper mod then increasing your CO settings? I did this to my 06 (had an 05 too) and it corrected the abrupt on/off throttle issue. I live at 6,200' elevation and regularly ride up our mountain out back (Sandias) to 10,400' and haven't experienced stumbling or surging. Hmmm.

Click to expand...

Seems a LOT of '07 bikes are experiencing this loss of power at high altitudes, threads and comments are popping up frequently.

Are you guys reporting the problem to the NHTSA? This will be the avenue to get some action with this problem. Calling Yamaha won't get you very far. My guess is you'll get you the usual generic horseshit response "never heard of this problem before?"

Sounds to me like a recall is needed for this bike, and sooner rather than later.