Running Rough after sitting in the sun

FJRHopeful · Jun 30, 2009

I have an '07 FJR and previously owned an '05 FJR. Both ran exactly the same way after sitting in the hot sun for an extended period. I ride my bike to work and live in Sacramento where it can get pretty warm in the summer. When I go to leave in the afternoon the bike starts up fine, but when I take off it feels like it is going to stop running. It sputters like it is gasping for air or fuel. I've opened the fuel cap prior to starting thinking possible vapor lock, but doesn't help. Once I'm going and can get the rpm's up and ride about 2-3 blocks at a pretty good clip the problem clears up. Both my '05 and now my '07 do this. Any ideas on the cause and a fix?

lazbm · Jun 30, 2009

Experienced the same twice on my '08 on a recent long trip to Utah. First time was after a long stretch when we sat at a Starbucks while the bike cooked in the 4 PM heat (close to 100F). After about 45 minutes, restarted the trip and the bike was stalling/starving. Raised the RPM a few times, and the problem disappeared within 5 seconds.

Don't remember the conditions during the second incidence, but it repeated again after a couple of days.

Bike mileage is less than 4000 miles.

feeger · Jun 30, 2009

Mine does the same. PCIII, and iridium plugs didn't fix it.

GunMD · Jun 30, 2009

My 05 has been known to do it after getting it good and hot, then letting it sit just a few mins before starting it and riding again (before it has a chance to cool). My friend's 06 does it too. I've heard it refered to as "heat soak", whatever that means...

johnny80s · Jun 30, 2009

It happens on my 0 every time I go to Vegas and its hot. I just got back from a trip there and my bike did it in the middle of the day after it had been parked for hours in the 100 degree sun.

RadioHowie · Jun 30, 2009

GunMD said:
My 05 has been known to do it after getting it good and hot, then letting it sit just a few mins before starting it and riding again (before it has a chance to cool). My friend's 06 does it too. I've heard it refered to as "heat soak", whatever that means...

DAMMIT GUN!

How we gonna convince these Gen II wonks their bikes are just BAD when a Gen I owner chimes in with the same problem?

That's time out for you, mister!

Back to the original problem, I'd kinda-sorta agree on a "vapor lock" condition aggravated by "heat soak". There's a LOT of heat "soaking" into the fuel rail when a just-run bike's sitting, possibly vaporizing gas in the fuel rail, preventing consistent fuel flow until the rail gets a cool down from cooler gas in the tank.

Might even be a bigger problem with a Gen II since there's not a positive return to the tank like there is with the Gen I's fuel return feed setup. Nowhere for a big old gas bubble in the fuel rail to go but into the cylinder when an injector opens, so with only vapor going in a cylinder instead of liquid fuel, you get a lean cylinder, no-fire stumble.

Fairlaner · Jul 1, 2009

got to be fuel percolation....

R

n1acguy · Jul 1, 2009

I've had it happen to my 08 a couple times after sitting in high temps. It's gotta be vapor lock. Maybe the fuel lines can be insulated. I've had signs of it happening on the freeway too in real high temps. I've had it stumble on me a little when I rolled it on at a steady cruise. Probably has to do with having to run oxygenated fuel all year long. I've heard the oxygenated fuel is less stable at high temps.

johnny80s · Jul 1, 2009

I bought a little day cover that bungies to the back and the handle bars and keeps the sun off the top of the bike. Hopefully that will help.

RsvlFeej · Jul 1, 2009

Note that EVERYBODY with the problem has a Cali bike. Another thread mentioned something to the effect of our special plumbing to the charcoal canister is probably the culprit. I was considering picking up the out of state tee fitting to bypass the canister, but haven't bothered yet.

Slappy · Jul 1, 2009

This is a common sense issue. The bike is warm enough not to have the "FI Choke" activate but the engine is still "cold" enough to still need it for a moment or two. When I say choke I am refering to the extra rpms the bike runs at when cold. Whatever temperature sensor that normally tells the ecu or what ever to add more fuel when cold to keep the rpms up until it can run senses the bike is "warm enough" so it doesnt tell the ecu or what ever to add the extra fuel there fore the bike runs rough until the operating temps get to where the bike runs normally.

As you can see from my description I am not mechanically savy but this makes total sense to me.

johnny80s · Jul 1, 2009

Slappy said:
This is a common sense issue. The bike is warm enough not to have the "FI Choke" activate but the engine is still "cold" enough to still need it for a moment or two. When I say choke I am refering to the extra rpms the bike runs at when cold. Whatever temperature sensor that normally tells the ecu or what ever to add more fuel when cold to keep the rpms up until it can run senses the bike is "warm enough" so it doesnt tell the ecu or what ever to add the extra fuel there fore the bike runs rough until the operating temps get to where the bike runs normally. As you can see from my description I am not mechanically savy but this makes total sense to me.

Mine will idle but when I give it gas or rev it it stumbles badly. Two or three blocks down road it fine. I think Slappy might be right?

Did I really say that?

FJRHopeful · Jul 2, 2009

Thanks for the feed back. Was hoping for a solution, but doesn't sound like anyones found one yet. I called the dealer and they said it sounded like a fuel pump. Think they are just looking for some service dollars. Just a little embarrasing to have it sputtering down the street when you first get going. So if anyone has a solution please share and I'll buy the beer. Cheers!

USAFFJR · Jul 2, 2009

FJRHopeful said:
Thanks for the feed back. Was hoping for a solution, but doesn't sound like anyones found one yet. I called the dealer and they said it sounded like a fuel pump. Think they are just looking for some service dollars. Just a little embarrasing to have it sputtering down the street when you first get going. So if anyone has a solution please share and I'll buy the beer. Cheers!

Easy solution: Let it idle for a couple of minutes before you take off. That's it. Works for me every time. If I try and hop right on and go (I have the same problem -- a CA bike that stumbles after running and sitting in the sun) it'll stumble for a little while. Makes me really have to work the clutch. However, if you just let it run for a couple of minutes (say while you put your gear on, load up the bags, whatever), you'll be good to go.

Other folks mentioned bypassing the charcoal canister. I've heard that works, but I don't feel like tearing the bike apart to get to it. I'd rather spend that time riding. <_<

not2shabby · Jul 16, 2010

Mine's been doing it too, really aggravating. It's a Cali model also, bought from a gentleman in Fla. Go figure. I wish I'd removed that @#$%ing canister when I did the valve check a few months back but I didn't even realize that's what it was at the time. Just wanted to get it back together and ride! Major PITA to put the bottom of the tupperware back together with it in there too. Grrrrrrr!

FJRBluesman · Jul 16, 2010

Gen1 superiority.

RadioHowie · Jul 16, 2010

FJRBluesman said:
Gen1 superiority.

:withstupidsmiley:

:jerry:

ShowMeMo · Jul 16, 2010

Yep... my 09 Cali model also does this (bought from TN dealer and live in MO so removing the CA emissions stuff if this is causing the issue would be of interest)... it seems to take a rev or two to clear up... is this only Cali models?

CHRIS_D · Jul 16, 2010

My also does this. So it's only CA bikes and the only difference from the others is the charcol canister. Hmmm I can see what next project will be in the future.

Running Rough after sitting in the sun

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