The Jerkiness of Jerky Motorcyle Throttles

[RaYzerman19]

Thx ionbeam. I don't think I articulated this correctly but what I'm truly wondering is if we could get rid of the abrupt throttle response off idle if the throttle cable pulley at the throttle body were 1) larger and 2) had a completely different shape. There's only so much you can do with the throttle tube. We could accomplish a lot more at the other end. Hope that makes sense.

Makes sense to me, the downside is having to turn the throttle further to get full throttle for those times when you want it.
I had forgotten about the throttle spring unwind.... it helps as your muscles can control a lighter load better. Also, set the throttle cable freeplay to zero.... sneak up on it while adjusting and stop when it is zero. Not good if you go too far after that zero point.

The other thing I use is a rubber band affair called the Original Throttle Boss..... have one on each bike, but unless you see old stock in a shop, you'll have a hard time finding one. It is small, and amazingly effective for its size. The new one being sold is wider..... I guess they were trying to emulate the Throttle Tamer..... anyway, you could get one and cut it down to make it narrower. This again lets you use your outer palm to add some control to the throttle roll on rather than relying solely on your wrist muscles.

 

[HotRodZilla]

You know, I hear the Prius has a pretty tame throttle. A couple of you should try one.

 

[lnewlf]

My '06 had a monumental jerk throttle....did all the usual stuff..[bJM, spring unwind, G2]..I accidentally set the idle at 1250 and that actually helped the tip in a lot. Also starts instantly. But the best fix of all happened gradually during the first six months or so of riding the scoot....I fixed the jerk in the saddle...

 

[GhidorahX]

My '06 had a monumental jerk throttle....did all the usual stuff..[bJM, spring unwind, G2]..<snip>....I fixed the jerk in the saddle...

@lnewlf:

Thanks for the info . . . I tried to search "BJM" here on the forum . . . didn't seem to find anything???? I got the "spring unwind" . . . and the "G2" is the aftermarket throttle tube??? I haven't looked at the options for awhile, waiting for the next service, but, also yes . . . "getting used to the bike/adapting/adjusting" . . . . But, "BJM" sounds interesting . . . .

Gx

 

[RossKean]

BJM = Barbarian Jumper Mod

 

[yeravener]

The problem was:

There is a slight bog and flat spot on opening the throttle which requires additional throttle in order to get the bike moving. When increasing the throttle slightly there is no RPM increase or torque available, and yes, the throttle cable is tight. On a slight hill with a passenger, I had to increase the RPMs to 2K in order to get past the flat spot and move the bike forward.....made me sound like a total clutch newbie (been riding for 46 years). Obviously it is less a problem with one person on the bike aimed downhill, but it is still there.

A quick blip of the throttle from idle to about 1/16 throttle in neutral illustrates the problem as a bog and then (delayed) rapid increase in RPM. Blips of greater throttle rotation than 1/16 just power through the bog and it is not as noticeable.

My parking garage at work has a speed limit less than the idle speed of the FJR in first gear (haha!). While rolling just off idle in first gear the engine runs rough and surges. Applying additional throttle to increase the idle by ~500+ RPM over idle, and thus past the flat spot, smooths the engine out.

I took the bike in [two days ago] for the 600 mile service and described the problem for the service manager and asked them to set the vacuum on each cylinder as close as they can, instead of the 10mm Yamaha specification.

The bike is brand new, so "dirty anything" [was] not likely the problem (though I can be educated). I figure I will get the cylinders synced, get past the 1K miles break-in threshold, and go from there. I haven't tried it in Touring mode because I am old school and want "all the power all the time with minimum throttle thank you". The other reason I have not tried it in Touring mode is because having dual modes is no excuse for one mode not being mapped correctly (potentially). The bottom line is I want it fixed in Sport mode because that is the mode in which I ride.

The solution was:

Well, I received my 15 ES back from the dealer after the 600 mile service. The service manager stated the off-idle bog was fixed, and if I had any further issues to bring it right back. Nice folks at Capitol Yamaha in Sacramento.

The minute I released the clutch leaving the parking lot I could tell they had fixed my problem via the synchronization of the intakes. There was appropriate torque to initiate movement of the bike with reasonable throttle, and I found as I rode that the synchronization had eliminated what had been a wicked vibration from idle all the way to 3500 RPM. The work also lowered the amount of "compression braking" experienced on closing the throttle from 4000 RPM at speed.

It now clutches normally from a start given a heavy bike with a tall first gear

. No driveability issues related to the throttle at all....normal FI throttle performance.

Could not be happier!!

 

[HaulinAshe]

My advice - don't bother with the BJM. Extremely small impact on the problem.

In descending order of positive effect on jerky off-idle throttle response...

* PowerCommander (PC-V now)

* Re-cam or replace throttle tube

* Larger, football-shaped grips (think about the geometry change)

* Cable slack adjust (make sure it doesn't go tight at extreme angles. Premature breakage of throttle cable leads to extreme stress on the roadside.)

* 3rd Spring Unwind

* If 2007 model, reset this list and place 2008 or later Throttle Body at the very top. (Hang out on Ebay to pick one up)

Side note - question - Why in the hell would you be in 1st gear negotiating a turn? Out of some roughly 30,000 to 50,000 turns I commonly ride, I would say less than five require 1st gear. And they are something like 20-degree inclines with the parallel pavement edges touching on a vertical plane. We're talking SERIOUS switchbacks!

Hit that damn turn with some speed and remember there is something called a clutch on the left side. Squeeze some pressure while you roll through the corner in 2nd gear and let the clutch slip a little. It really doesn't mind. In fact, it enjoys the attention.

 

[GhidorahX]

The problem was:
There is a slight bog and flat spot on opening the throttle which requires additional throttle in order to get the bike moving. When increasing the throttle slightly there is no RPM increase or torque available, and yes, the throttle cable is tight. <snip>

I took the bike in [two days ago] for the 600 mile service and described the problem for the service manager and asked them to set the vacuum on each cylinder as close as they can, instead of the 10mm Yamaha specification. <snip>

The solution was:

Well, I received my 15 ES back from the dealer after the 600 mile service. The service manager stated the off-idle bog was fixed, and if I had any further issues to bring it right back. Nice folks at Capitol Yamaha in Sacramento.

The minute I released the clutch leaving the parking lot I could tell they had fixed my problem via the synchronization of the intakes. There was appropriate torque to initiate movement of the bike with reasonable throttle, and I found as I rode that the synchronization had eliminated what had been a wicked vibration from idle all the way to 3500 RPM. The work also lowered the amount of "compression braking" experienced on closing the throttle from 4000 RPM at speed.

<snip>

Could not be happier!!

@yeravener:

Thanks for posting this information, all of the problems mentioned are similar in nature to what I experience, including "compression braking" when closing throttle, etc . . . and good to know that possibly doing a good throttle body sync could fix the problems . . . . The FJR is probably the most competent bike I have owned, but these FI problems compromise what is truly a fine motorcycle. Taking a trip next week and after that I might be closer to the service interval, pop the hood and try messing with the spring and synch, etc.

@Haulin:

Also appreciate the priority listing of solutions . . . couldn't get the cursor under this quote . . . . GX

My advice - don't bother with the BJM. Extremely small impact on the problem.In descending order of positive effect on jerky off-idle throttle response...

* PowerCommander (PC-V now)

* Re-cam or replace throttle tube

* Larger, football-shaped grips (think about the geometry change)

* Cable slack adjust (make sure it doesn't go tight at extreme angles. Premature breakage of throttle cable leads to extreme stress on the roadside.)

* 3rd Spring Unwind

* If 2007 model, reset this list and place 2008 or later Throttle Body at the very top. (Hang out on Ebay to pick one up)<snip>

 

[mcatrophy]

. . . couldn't get the cursor under this quote . . . . GX

Click the little switch in the top left corner

This gives you the simple view, you'll see the text ending in "[/ quote]". You'll be able to put your cursor after that, then put in a couple of new-lines. Click the little switch to revert to the normal view, you'll be able to put your cursor after the quote box.

 

[GhidorahX]

@mcatrophy:

Thanks for the pointer, thought it might have been because I'm still in OSX 10.4.11 on my home desktop unit . . . .

Gx

 

[mcatrophy]

@mcatrophy:Thanks for the pointer, thought it might have been because I'm still in OSX 10.4.11 on my home desktop unit . . . .

Gx

Nothing to do with your OS, it's a quirk of the way the forum software plays with what you write and quote. It's not hard to get it into that "impossible" state.

 

[Brodie]

Throttle control.

Try this... Slow down for the turn a bit sooner and a bit more, then add a touch of throttle to take up the driveline backlash and settle the bike; and then turn in. You will have more control of the bike with smooth acceleration throughout the entire turn. If applying the throttle before turn in makes it seem like you're taking it a little hot, then you didn't slow down enough, or soon enough.

I've been riding since the late '60s but had to work hard to learn this new technique. I've always entered into the turn with the throttle off, still slowing, letting the turn scrub off the last bit of speed; and then giving it the gas mid turn. The driveline snatch happens mid turn and always upsets the bike.

Slow in - quick out; smooth is the goal.

Exaggerate the early slowing when first trying this technique to give you time to settle the bike with your right hand. After a while it will become a learned action, second nature and the act itself will quicken up.

Brodie

 

[DeSudet]

I find myself in the bad habit of trailing the rear brake as I turn in and ease onto the throttle at the same time. The trailing brake seems to minimize the effect of driveline snatch IMHO. I probably should break myself of that sooner rather than later... Of course, the only riding I seem to do lately is commuting and the only places this applies is turning into the parking lot at work and the driveway at home. Everything else is 80mph interstate.

 

[GhidorahX]

Thanks for the tips gents . . . but I'm like a "Randy Mamola" type rider, having a "plan" and "riding the plan" doesn't work for me . . . I'm all over the place, late-braking, late apexing, early braking, early apexing . . . on the gas, off the gas, looking around at the scenary instead of watching out for bicyclists hanging out in my lane in the middle of a blind corner . . . not paying attention to the machine and its "needs" . . . oh, also, trailing the rear brake, and, um, not trailing the rear brake . . . like Randy used to do . . . . : - )

Anyway, considering that a fair number of posters here have recommended the PC-V as the #1 choice, that is an indication that Yammie doesn't have the FI dialed in very well. I am interested to see if I can find a competent mechanic in west-side of LA that could dial in the throttle bodies very accurately; however, I had a Throttle rocker around from when I had rented the very consummately smooth and quick Konk14 a couple years back, and I put it on the 09er and did my tight switchback ride today . . . and perhaps because my wrist was lazily keeping some gas on even when I backed off . . . the problem (the extreme throttle jerkiness of it all) was much less intrusive to the ride . . . .

Possibly the machine is starting to figure out what my needs are, rather than vice versa . . . when it's good, it is very good.

Gx

 

[HaulinAshe]

Anyway, considering that a fair number of posters here have recommended the PC-V as the #1 choice, that is an indication that Yammie doesn't have the FI dialed in very well. I am interested to see if I can find a competent mechanic in west-side of LA that could dial in the throttle bodies very accurately;...

It has nothing to do with dialing-in throttle bodies. It's all about EPA emission standards and the ongoing demand for leaner running engines throughout the entire power envelope. The PC-V does what the ECU cannot. The PC-V errs on the side of performance, while the DOT-driven ECU/FI must stay within certain "acceptable" emission limits.

 

[GhidorahX]

@HaulinA:

Cool. How then do you explain my experience with renting, twice, the Konk14 . . . and not having similar jerky throttle problems with the FI? Smooth as silk all up and down the rev range, no problems with being in any gear, in any turn???

Bone stock . . . .

 

[mcatrophy]

Get a Gen 3. Fuelling is so much better all through the range than any year Gen 2.

 

[Bounce]

@HaulinA:
Cool. How then do you explain my experience with renting, twice, the Konk14 . . . and not having similar jerky throttle problems with the FI? Smooth as silk all up and down the rev range, no problems with being in any gear, in any turn???

Bone stock . . . .

Explain the performance AND fuel efficiency AND clean emissions that VW TDI engines were getting. Do it before the discovery was reported by the media. Some times the mfgr does stuff that the consumer can't suss out without expensive diagnostic tools. Most often suppositions are addressed with SWAGs that more or less work for practical purposes and are then validated over time (or not) by others trying the same or different SWAGs.

In your example, I'd SWAG that the difference between the FJR and the Konk14 is in the performance curve if the two motors. The FJR has tons of torque throughout the curve so that small inputs are very noticeable. Meanwhile the Konk14 has a motor more like many race repros where the majority of the response is in the upper bands so that small throttle inputs at lower RPMs are buffered by the motor itself.

Why else would a Konk need 6 gears and that, in 2015, Kaw lowered first gear to reduce the need to slip the clutch on take off.

 

[FJRRYDER]

Sometimes I long for the days when I would just jump on the bike and ride it, without worrying about every freaking detail possible. I think I am getting used to the throttle, though, the jerkiness seems to be going away, a combination of clutch action and right wrist getting the feel.

 

[GhidorahX]

Question . . . are there any FJR operators in SoCal who have the G2 throttle tamer installed who also get to the Rock Store on a semi-regular basis that could meet me there on a Saturday morning and field some questions about their experience with it? I don't want a test ride, just do a twist test comparison to my 09 stock throttle to the G2 . . . seems like this relates to Gen2 throttle operation . . . .

The "herky-jerky" problem has more or less been "compensated for" with the throttle rocker keeping the gas slightly on . . . now the problem is relating to slow start times away from lights due to what, heavy throttle spring and tall first gear???? Wondering if the G2 has a cam that turns the throttle further than stock so that the bike could go faster than 65 and not require a re-grip on the throttle to get that done???

I tried to get LACyclesport to "release" the throttle spring one turn, but they claimed that would be a "violation" against the manufacturer's code or something . . . haven't found a mechanic on the westside who will work on the bike to do such "modification" . . . . So far the 09 has been very "safe and sane" . . . a gentleman's almost express of consummate smoothness . . . doesn't do anything kawazzy . . . which is fine, but not so great for dicing on the freeways . . . . Anybody around with the G2??

Gx