FJR Acting Up 'sup Wit Dat?

Has anyone had some problems with intermitent hesitation? While riding Tuesday I was puttzing along around 60mph and it was like the fuel was shut off for a split second. I wrote it off thinking that maybe my throttle hand had spazzed out. Then about 15min later it did it again hesititating 3 times back to back. I grabbed a hand full of throttle and wrung it out a little. I am thinking that my fuel filter is in need of replacing or maybe some bad gas. Even though it wasn't spark knocking, I topped off with premium. (about a half-a-tank) What do you professional feejer pilots think? I just rolled 1300 miles on the '05 ABS.

Thanks,

Moby one

Some people have had problems with the TPS. You might want to have your dealer check it out if things don't get better.

Ditto on the tps. 'specially if it seems to occur at the same aprox throttle opening every time.

Thanks guys,

No hesitation today.

Rode 50 miles but hardly ever had the throttle at that same mph for long. Dry pavemenet and no bugs or side cases to slow me down. I'm going to have my yamaha guy take a look at it on Saturday. He just received some high-tech $600.00 TB Sync tool (since the dealer didn't do mine @ 600 cuz it was running ok). <_<

I will keep ya posted on any changes. Thanks again.

MO

Your symptom also sounds like water in the gas. Maybe it's not the case but it could be a consideration.

It must have been some contaminated fuel like C&C said. I filled up with the good stuff and have not had another problem with the hesitation. Company Holiday today and the road is now dry....going riding.

Later-

MO

I don't know if you could call it hesitation, but when my '05 is cold, it's like the fuel cuts out ofr a second, and then comes back on. This typically happens several times until the bike heats up slightly. It is usually accompanied by a kind of "knock", but not like engine knock on bad gas or a bad rod bearing, etc.

Could this be the TPS gremlin? What do you think? The bike has slightly over 1000 miles on it. <_<

Comleader,

I had the "hesitation" problem after warming up to two bars before departure. Then I had about 20 or so miles on it when it acted up. It did it again a little while later. I have since put about 1000 miles on it without so much as a hiccup. The only thing I do for sure now it buy gas at busy gas stations. Not always easy to do in Northern Michigan but I try.

Later

mo

Water in the gas was my first thought. Kinda spooky when it happens, ain't it. Even worse when it happens in an airplane. Talk about "pucker factor"! Don't ask how I know.

Yes, buy gas at busy stations. If the tanker is there pumping into the tanks, go someplace else, too.

Perhaps you might want to run some of that gas "dryer" through there to "absorb" the water?

How hot was it when you were riding? Were the conditions the same? That bike can still be pretty hot on the outside when the inside is only two bars. Excess heat might exacerbate an intermittant TPS problem? (Talking through my hat here...)

Glad it sounds like your gremlin took a powder..hopefully.

The bike was running on two bars and as i recall it was about 75 degrees outside. The gremlin has gone (maybe it went out on the wing of that big airbus, ya know twilight zone the movie) I may be reaching here. Rocket, only one more and you are @ 100 posts (quality posts too, i might add)

Later, going riding,

mo

I have been looking for this problem, figured someone else had it - here is my story on it, and I do not think it is gasoline related.

Basics - 2005 FJR - got it July 2004 - I have 10,500 miles on it - had a 4000 mile TBS service, all other oil changes, etc... as required.

Recently (4 weeks ago?) very hot humid Northeast day (Connecticut) - I ride 2-3 hours straight, started with a full tank - bike starts lurching, sounds like what you describe exactly - off the throttle causes a big down, then open the throttle and it surges - VERY uncomfortable - feels like it is running out of gas.. I am thinking WTF is wrong? Have a half tank - Soooo - I keep going, end up in very bad traffic - now the thing is really going up and down and the gas tank is so hot I cannot put my legs against it (I am not making this up - it was burning hot).

I start thinking what about a vapor lock type thing? Is it possible? I stopped, opened the tank and let it air out - I have about a 1/4 tank now - add 2 gallons so I have 3/4 of a tank, and the problem completely goes away AND the tank cools right off within a very short time. I'm thinking o.k. - it didn't like the long distance non-stop very hard ride (I enjoy pushing the bike) on a really hot day - I had a vacuum created in the tank. No more problems for a few days - then it does it again and I was able to fix it the same way - by opening the tank. By the way I always use 93 octane from a name brand station - and where I am they are busy stations.

What I found today - nice 75 degrees, no heat, had a passenger - the surging returned and opening the tank does NOT solve the problem - it is really bad at about 3500-3800 rpm - somewhat better but still exists at 4000-4300 rpm.

I get back from the ride, bike cools - I am a little pissed because I am wondering if it really is vapor lock at all or maybe the fuel pump? Fuel Filter? I JUST had the TBS and new plugs and air filter done two days ago - so the problem existed before and after the service.

However, this evening, with just me, it did not surge at all.

Very very strange...

Any of you have any similar experiences that do NOT seem to be TBS/plugs/air filter OR gasoline quality related?

Thanks for ANY information - I love this bike and ride it a lot - just getting concerned it might be a bigger issue than I thought -

Allen Hamlin - Connecticut STAR Chapter 168, Harttford

FI does not get vapor lock. Quit running the 93 octane. Using brake clean, flush the vent line at the back of the filler cap. Pull side covers (silver and black), make sure vent lines aren't pinched after tank was lifted for TBS. Using diag screen, check TPS for full operation. Hot gas (especially in gas where high octane achieved through use of ethanol) can boil in the rail and act weird. Lift tank and check connectors for TPS, injectors, and check vac lines for loose fit or missing TBS access caps.

Wow - Thanks for the fast response! I will go down to 89 Octane? Also, this evening I did make sure the vent hoses that feed down to the bottom of the bike were NOT getting pinched - I think that they MAY have been after the service, can't be positive. Hey, I'm just happy now I thought of that on my own!

I will flush the vents.

Stupid, stupid question - sorry - what is the TPS? (I gather the TBS is throttle body synch)

Thank you for your response - I will do as suggested.

Allen

TPS = Throttle Position Sensor.

Radman rocks!

I've been fillin up with 87 since the origional problem and have not experienced it since.

mo

I've been fillin up with 87 since the origional problem and have not experienced it since. - mo

Click to expand...

Yet another data point about never using any higher octane than needed to prevent knocking. Even Yammy recommends regular unleaded unless you have knocking.

Suggest checking your fuel tank vent lines to make sure that they aren't plugged & causing you to pull a valcuum in your tank. The pump can only overcome so much tank valcuum & still pump fuel. I've seen this happen on other bikes although they weren't fuel injected. With the vacuum in the tank gravity couldn't overcome the vacuum for fuel to flow. The symptoms occurred during/after long rides at higher speeds, & then when the gas level got lower. Opening the gas tank cap temporarily eliminates the vacuum & temporarily solves the problem. Good luck.

Actually, the fuel pump on the Feej is powerfull enough to have collapsed tanks.

So far, I have seen a pretty good improvement - I made sure there were no pinches in the vent lines under the left side covers - went through a tank of 89, had a couple little hiccups, re-filled with 87 - had no problems for the first 1/4 tank - I will continue the 87 Octane and keep an eye on it.

Here is another question, then - there are TWO black hoses under that side cover, running right past the air filter - I am assuming one of them is the tank filler cap vent tube - what is the other one?

I have never removed the tank myself, since it has not been necessary (until now) - I plan on taking it off this week to check out the items listed in RadMan's response - does the other hose originate from another part of the tank? Another component under the tank?

Thanks - I'm always learning... I am glad I found this forum.

Allen