Throttle Abruptness

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bill lumberg
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Throttle Abruptness

Post by bill lumberg » Tue Dec 25, 2018 9:20 am

2018 FJR. From off throttle to on throttle, there is an abrupt jerk, like rolling on goes from 0%-5%. Tour or Sport mapping. Not really noticeable underway, but in a parking garage or doing tight figure 8’s, it’s almost impossible to finesse past it without getting yanked. Works both ways, rolling on and rolling off. What would you check or adjust?

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Re: Throttle Adjustment

Post by raYzerman » Tue Dec 25, 2018 10:08 am

Not sure, Bill. Is it any different than the '14 you had? The throttle by wire system automatically raises rpm when you slightly release the clutch (ECU controlled when it senses clutch switch), this to prevent stalling on take-off. Should be 100 rpm or so. Perhaps try adjusting clutch lever to one setting either way to see if you can better control it. Check to see how much rpm increases when the clutch switch engages (can be more accurately read with OBD or dealer computer). The other thing I'd do is flush/bleed the clutch.
The FI system has two sensors, accerator position switch and TPS. Both of these give inputs to the ECU on throttle position. Perhaps a tweak adjustment may be needed. On Gen3 prior to '16 we have a diagnostics screen to read the values. '16 and on got OBD, however, to date all I have seen is a throttle position percentage reading on the OBD, and I presume that is reading the TPS. I'd think the only true readings will be available from the dealer's computer with the Yamaha proprietary software. Convince the dealer it's a warranty issue and have them look at it (to determine if APS or TBS needs adjustment).
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bill lumberg
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Re: Throttle Abruptness

Post by bill lumberg » Tue Dec 25, 2018 12:50 pm

Yeah, totally different from the 14. Almost a knock when the grip gets far enough. Nothing major, just something minor out of adjustment.

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Re: Throttle Abruptness

Post by extrememarine » Tue Dec 25, 2018 9:35 pm

On a Gen 2, a Powercommander and map resolved that off/on throttle 'jerk' or 'abruptness' you describe. I have no idea if that's an option for the '18.

But you mention this is at slow speed; I'd suggest using (slipping) the clutch a hair to get through that off/on/off transition zone at low speeds. Add some rpms, drag a little rear brake, slip the clutch and you can spin that bike around in circles inside a parking space. These are thing 'go-to's' from my MSF days; I used my '04 and my Harley for running demo's - the Harley would let me crawl around the range at idle just working the clutch. The FJR required an entirely different technique to run the cone and u-turn demo's.
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Re: Throttle Abruptness

Post by wheatonFJR » Tue Dec 25, 2018 10:01 pm

I'm sure Bill L. can maneuver his 18.

However, since it is brand spanking new, he'd probably rather it operate as smooth as his 4 yo bike...which is why he started the thread.
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Re: Throttle Abruptness

Post by Uncle Hud » Tue Dec 25, 2018 11:09 pm

bill lumberg wrote:
Tue Dec 25, 2018 9:20 am
2018 FJR. From off throttle to on throttle, there is an abrupt jerk, like rolling on goes from 0%-5%. .... What would you check or adjust?
Personally, I would not drink before riding.
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Re: Throttle Abruptness

Post by bill lumberg » Wed Dec 26, 2018 6:36 am

Wheat probably has a point. I am a long time friend of the friction zone and I can slow crawl and perpetrate cones all day long. This is a throttle transition issue rather than a staying upright one. Next time I get a chance, I want to get one of you guys to take it on a spin around the parking lot to see what I’m talking about. Not a Maggie Valley moonshine spin around the parking lot, more like a Walmart/Diet coke spin around the parking lot. Im not entirely sure something didn’t get tweaked during helibridge install. Not so much cable play, but maybe throttle reassembly.

And thanks for the tip, Hud.
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Re: Throttle Abruptness

Post by extrememarine » Wed Dec 26, 2018 7:24 pm

Bill - This detail:
Im not entirely sure something didn’t get tweaked during helibridge install.
Did this develop after installing the Helibridge, or was it there before? Maybe not noticed before. You've ruled out the easy fixes (rider input adjustments), so comparing to another '18 would be a good way of vetting if it's your bike or 'normal'.

Sometimes, it's hard to really nail down something we "feel" on the bike - someone else may not notice or be bothered by it.


bill lumberg wrote:
Wed Dec 26, 2018 6:36 am
Wheat probably has a point. I am a long time friend of the friction zone and I can slow crawl and perpetrate cones all day long. This is a throttle transition issue rather than a staying upright one. Next time I get a chance, I want to get one of you guys to take it on a spin around the parking lot to see what I’m talking about. Not a Maggie Valley moonshine spin around the parking lot, more like a Walmart/Diet coke spin around the parking lot. Im not entirely sure something didn’t get tweaked during helibridge install. Not so much cable play, but maybe throttle reassembly.

And thanks for the tip, Hud.
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