FJR throttle delivery?

[GAPS]

Im coming from a Bandit 1200 which after much fiddling has super sweet throttle delivery. Mixed reports I've read on the FJR, some say it is not so nice when picking up the throttle mid corner, in traffic, etc... is this just whimpy moto snob snivel or a real deal?

 

[ohiofjr]

there is a hitch in the throttle response just off idle where the injection mapping switches over to useing the oxygen sensor. a power commander cleans that up giving perfect response. that is the only time there is any imperfection. in the real world the only time abrubtness occurs is trolling thru slow and painful traffic and even then its simple enought to just run a few rpm higher and avoid it.

 

[madmike2]

....some say it is not so nice when picking up the throttle mid corner, in traffic, etc...

Why would one be picking up the throttle mid-corner? I always thought the best technique is to roll on the throttle through the corner and power out once one sees the corner exit (Don't flame me, I know there are "those times"...). Mine can be a little "jerky" @ 25 mph, right at the RPMs where the computer searches while in 3rd gear. I've never had any trouble in commute traffic, or maybe I don't notice because I "automatically" choose the best gear now that I'm used to the FJR.

As was said, there are those who want to eliminate any problems, and the Power Commander II does the job (though I don't have one).

 

[FJRPierre]

When I had a slack throttle cable it made for a jerky ride. Someone pointed out the cable adjustment near the throttle, which can eliminate/adjust the amount of slack in the throttle cable resulting in less jerky minute throttle adjustments.

 

[FJRMGM]

it's awful - one minute you are going slow and the next minute you twist the throttle and WHAM!! - WARP SPEED..

It's so bad I could barely stand (or sit) to ride it for the 21,100 miles last year.

 

[radman]

When I ordered my throttle, delivery was nice and smooth, with the UPS hottie even smoother............

 

[brazos parker]

Very nice throttle delivery, Rad. Very nice, indeed! :clap:

 

[jbay]

I came off a 97 Bandit 1200 with a jet kit and an 01 Bandit 1200 with the plug drilled out and richened up a bit . I still had the off , on abruptness in both that I couldn't dial out . The FJR is much much better no more minute throttle change annoyances . The tight twisties are much more fun now . Hope that helps.

 

[Penforhire]

Madmike, "best technique" doesn't always meet "real world." When you over-cook an entry do you just coast through the rest of the turn?

My FJR's throttle is very sensitive in the off-to-on transition (more than other bikes). I have the recommended amount of cable slack so we're talking injection map here. Just not bad enough for me to spend on the PCIII (yet).

 

[jestal]

I think the shaft drive also affects the perception of throttle abruptness. Bikes with chains have a bit of damping from coast-to-drive and drive-to-coast transitions as the chain slack is picked up. The shaft drive just has the normal driveline lash which can exacerbate the throttle response feel....especially at very low speeds. At very low speeds learn to lock the throttle slightly open with your wrist and control your speed by dragging the rear brake to avoid any on/off throttle lurchiness.

 

[GAPS]

First let me say, 'NICE FORUM', as an FNG I have been really enjoying myself reading all about the bike Im about to recieve. Lots of great info I have found already.

Again, my Bandit has very predictable off idle throttle response. Nice feature on an unfamiliar backroad where you might not be in just the right gear, entered corner too hot etc.... On the other hand mi padres Duck Monster has very abrupt repsonse just off idle, much less forgiving of a ham fist or bone headedness. :dribble: Long time chain driven guy wonders..., does the FJRs shaft drive hub contain a rubber cush like most chain drive setups? Lack of drive line/chain slop = more repsonsive to input?

Soon enough I will be able to form my own opinion of the FJR, for now I am sure enjoying listening to all of yours. Thanks for all the input.

UPS... :clap:

 

[madmike2]

............I always thought the best technique is to roll on the throttle through the corner and power out once one sees the corner exit (Don't flame me, I know there are "those times"...)..............

Uhm, Penforhire, "...'best technique' doesn't always meet 'real world'...."

And I thought I covered that in my post, but oookkaaaaayyyyy! I never overcook a corner :dribble: (hooh-boy). Still, coasting is not an option if one wants to maintain chassis/suspension loads and control of the machine. I suppose I'm fortunate in that mine doesn't sem to transition all that badly. Or else I'm very smooooth and lucky. :haha:

 

[Centerline]

I find myself feathering the clutch frequently in the corners which completely cuts out any driveline lash or abruptness of the fuel injection system.

 

[hippo]

I was hoping for a dual-butterfly or vacuum piston on the throttle bodies for the FJR since it was a pricey motorcycle -- I guess Yamaha didn't feel it was necessary.

The jump to EFI has made on/off throttle transitions WORSE than a well tuned set of carbs.

In a traditional set of CV carbs, the rider controls the butterfly and engine vacuum controls the carb slide. Because fuel is metered mainly by the slide lifting the needle out of the main jet and the slide is controlled by engine vacuum, there is a smooth transition between on/off throttle. Also, a carb is always dribbling fuel into the engine, helping smoothen the transition.

A single butterfly EFI system is really abrupt. When you twist the throttle, you move the butterfly, immediately and suddenly changing airflow to the engine (there is no vacuum slide to smooth the transition). On top of that, most bikes use a "coasting cut-off" system that completely cuts fuel at zero throttle. So, you get two things when you crack open the throttle from zero. 1) the engine suddenly gets a momentary drop in intake when the butterfly opens and 2) the injectors go from zero fuel to injecting fuel. The engine bogs then gets hit with a lot of fuel. BANG! Super jerky on/off throttle response.

The manufacturers have tried several methods to reduce this problem.

The cheapest way was to use more finely misting injectors. A finer fuel spray allows finer applications of fuel. The problem then ends up being that you can't pump enough fuel at WFO, so they added a second set of injectors. Typically, a lower set for regular riding and a higher mounted upper set for WFO throttle openings. Buell tries to solve this problem by allowing the injectors to stay open at zero throttle like a carb, smoothing the "hit" on open/closed throttle.

This still didn't solve the problem of the butterfly causing the engine to bog when it first opens, so the manufacturers tried to recreate the vacuum slide by either adding another (computer controlled) butterfly or an actual vacuum piston to the throttle bodies in an attempt to maintain consistent airflow.

The latest systems now are throttle by wire, like the R6 of new BMW K bikes. On both, a computer completely controls the single throttle butterfly and opens it to provide fuel.

What makes the throttle on/off transistion even worse is EPA requirements to run the bikes extremely lean.

On the FJR, with its single butterfly, the best we can do is to richen up the leanness which should help a lot. The best would be to get another throttle butterfly in there to help maintain intake velocity and richen the mixture, but that isn't going to happen unless Yamaha does it.

I'm waiting on my FJR, but I doubt it will ever be as smooth as my track bike (ZX-6R with dual butterflies, dual injectors and PCIII which makes the Kawasaki about as smooth as a good set of carbs).

 

[throttlejockeyTJ]

IMHO the FJR on letting the clutch out has the grunt torque feel of a Railroad engine.

Throttle delivery is linear (not snappy. The more throttle you roll on the more power is there. It is very controlable. However the front wheel can get off the ground, and one in the neighbor hood of 300 lbs & with pillion got the front end up significantly at 85 mph. going over a rise. Throttle must be used judicially in the first three gears in the wet. Max Torque is in by 3000+ rpm.

I think that answers it pretty well.

 

[markjenn]

The cheap trick to improve off-idle thottle response is simply to raise the idle speed. Try it if you haven't alreayd.

My take is that the stock FJR is decent by not superb in throttle response. I haven't felt the need for a PC, but we all have different sensitivities to this sort of problem.

- Mark

 

[NovaFlyer]

Anyone try this guys "smoothness" map for a PCIII ?

*clicky*

 

[Bike Effects]

Anyone try this guys "smoothness" map for a PCIII ?
*clicky*

I am using this map and it is flawless. I have none of the problems mentioned here.

 

[Bounce]

Anyone try this guys "smoothness" map for a PCIII ?
*clicky*

I am using this map and it is flawless. I have none of the problems mentioned here.

+1

AND I've adjusted out ALL the slack in the throttle cable.