Herky Jerky Throttle

[zenwhipper]

Folks-

Took me '08 on a 1500 mile round trip to Montana. The bike is doing something I never noticed before. If I ease up on the throttle, just ever so slightly to maintain a constant speed, the bike tends to get a bit herky - jerky. Its kind of like the bike throttle stumbles, and then the bike starts to stutter (for lack of a better term) up and back as if the throttle is going on/off/on/off/on/off. Its more annoying than anything really. If I give it throttle or let it decel with no throttle it goes away.

I'd appreciate any comments or thoughts. I did some pre-post searching but was not sure how to describe the issue nor the appropriate search terms.

Scott

 

[03HiYoSilver]

Scott,

Have you done a TBS yet? If not, you may want to do this and also you may want to check your TPS (Throttle Position Sensor) they have been known to go bad and do exactly what you are experiencing.

TBS https://www.fjrtech.com/getdbitem.cfm?item=21

Barbarian Mod GenII https://www.fjrforum.com/forum//index.php?s...st&p=395004

TPS/Misc Tests

https://www.fjrforum.com/forum//index.php?s...st&p=127397

Good Luck on your solution.

 

[LAGO RUNNER]

Did you have your throttle body synced at 600 miles?

 

[SkooterG]

Power Commander.

 

[zenwhipper]

Did you have your throttle body synced at 600 miles?

Yes. At least that is what the service receipt said.

Scott

 

[Jagermeister]

This is a long-shot:

Were you at higher altitudes?

I ask because a local dealership has been known to "swap" parts. Could you have one of the Altitude-Sick 07 ECU's?

 

[Bull]

I'd suggest the PC111 also. or the barbarian jumper .....

 

[03HiYoSilver]

Yes. At least that is what the service receipt said.
Scott

Scott, hate to say this, just cause it is on the receipt, does not mean it is done...don't ask me how I know this.

If you have the wherewithal, I would check this out yourself and I think you will be surprised.

 

[Hara]

Hi Scott,

I seem to have a similar problem with my 2001. Have you found a solution or the cause of the "jerkyness". It's not really a problem on my bike except that it makes it uncomfortable on low rpm when riding on torque at low and stable rpm. I've had to start using the clutch whereas before I'd just ride on the torque. Have you noticed a feeling of reduced power too?

Best,

Hara

 

[Capt. Bob]

Ditto on the ECU.

It was solved (?) on the 08s but maybe you got one with an older (06/07) part from the Factory.

 

[L2M]

Where did you get the TBS done? I asked around at different dealers before buying my Morgan Carbtune and found that the dealers in the south Seattle area (RMC, Seattle Sports Plaza, I90 Motorsports) didn't believe the TBS to be necessary. They basically wanted to do an oil change and check torque on some bolts. Wouldn't surprise me if they charged you and didn't do anything. I experienced the same feeling on my 07 until I did the TBS. No problem since.

 

[RsvlFeej]

Hi Scott,I seem to have a similar problem with my 2001. Have you found a solution or the cause of the "jerkyness". It's not really a problem on my bike except that it makes it uncomfortable on low rpm when riding on torque at low and stable rpm. I've had to start using the clutch whereas before I'd just ride on the torque. Have you noticed a feeling of reduced power too?

Best,

Hara

This is the link to cleaning the corrosion off your main wiring harness:

https://www.fjrforum.com/forum//index.php?s...mp;#entry268059

That helped several people with minor but irritating stumbling engine gremlins.

I also smoothed out a bunch of hesitation and got quite a bit of power back by running SeaFoam at 1 oz./gallon for 4 or 5 tankfuls of fuel. I think I had at least one injector getting gunked up. Description on the can of where, how and why to use SeaFoam reads like a classic snake oil pitch, but the timing of when stumbling decreased and I got power back sure coincided nicely with the addition of the stuff (I think around the third tankful, things started to get better). Maybe the snake-oil worked, maybe something else fell into place. I dunno. I dumped some SeaFoam into both a small 4-stroke motor and a small 2-stroke motor that have some partially varnished up fuel lines. If I do nothing else and see improvement in both, I may have to quit calling it snake oil.

Still have some herky-jerky on my '05 - feels like I'm running straight into very light gusts of wind - my dealer suggested a power commander or BJM, but for the first 50K miles, I never felt the little wind gusts, so I'm gonna keep tinkering with stuff (until something major breaks, like usual). Just bought a Carbtune, so I'm gonna try for the perfect TBS. Much discussion of the "surge" in the old boards, too. Search using the google link below for more info. My keywords were "synch", "rpm", "surging" - lots of info for both Gen I and Gen II.

https://www.google.com/coop/cse?cx=00202365...8%3A2jptjgyclxq

 

[TheAxeman]

Power Commander.

End of discussion.

 

[El Toro]

A lot of these problems go away with better gear selection, appropriate gloves, and a stronger wrist for better throttle modulation.

 

[Hara]

Hi All,

i've been surfing around to try and solve the problem. Came across a French FJR forum where one guy seems to have found a fix of sorts:

1/ he checked the TPS for correct voltage (0.63 to 0.73). It was ok

2/ he checked the Diag D1 for closed and open throttle readings were 17 and 100. Values ok

3/ checked all cylinders on a carbtune meter and all were matched.

4/ checked air bypass screws (under rubber caps on ramp) - 1/2 turn / 3/4 turn / 3/4 turn / 1 1/4 turns (i.e. cyl 1 to 4)

after that he closed all air bypass screws (contrary to Yamaha tech docs) and measures the difference between all cylinders. slight difference between 1 and 2, same for 2 and 3, big diff on 3 and 4.

rebalances the butterfly screws then opens up all four bypass screws by one full turn.

It would seem that the ramps are pre-set by the subcontractor for the average bike. Bike is said to be much smoother and plenty of torque. Seems the bike doesn't like tight air bypass screws and large differences between cylinders.

I have not tried this yet since I don't have a carbtune ramp.

The solution is worth exploring I think.

Good luck to all and hope this helps some.

 

[El Toro]

The PC is touted as a solution to the problem, and it could be a "solution" if the problem is the low end of the fuel map (low TPS and low engine rpm region of the fuel map).

Its a complaint that you find with many bikes equipped with EFI. My solution is to get up out of that part of the map, with a higher gear and slightly more open throttle, but it requires pretty accurate throttle modulation at these lower ground speeds, and the stiff actuation and return on the FJR make this difficult, at least until your right wrist/forearm come up to speed. Lots of riding helps with this. I think the complaints about the stiff throttle are legitimate, but I also think (based on my experience) that as your muscles adapt, it becomes more natural. Heck, it even makes the throttle on the other bikes seem downright wussy.

 

[zenwhipper]

Where did you get the TBS done? I asked around at different dealers before buying my Morgan Carbtune and found that the dealers in the south Seattle area (RMC, Seattle Sports Plaza, I90 Motorsports) didn't believe the TBS to be necessary. They basically wanted to do an oil change and check torque on some bolts. Wouldn't surprise me if they charged you and didn't do anything. I experienced the same feeling on my 07 until I did the TBS. No problem since.

I got the bike at Adventure Motorsports in Monroe, WA. They also did the 600 mile service w/ a TBS according to the receipt.

Scott

 

[zenwhipper]

I just got back from a 500 mile round trip. It can happen at all gears, in all elevations. I've seen some posts that may suggest rider error - but it really just feels like the bike does not like maintaining a smooth engine speed by holding the throttle in one position. I'm tempted to just go buy a PC III. But I got a Mac and therefore can only use the stock map provided with the PCIII. Also- instead of spending 300 bucks - I should start a more methodical, root cause, hopefully cheaper approach to see what it is.

Thx

Scott

 

[radman]

Hanky-Panky and/or Achy-Breaky throttle is a much worse, and more difficult to resolve condition.