Anyone have an idea what this is? The mags are indicating that a progressive throttle cam type device has been added to all of the 06 bikes to reduce the effort to twist the throttle. Could this be fit to an earlier model? Seems like it might be in the mechanism by the handle bar?
Progressive throttle cam
- Thread starter yamahlr
- Start date
Help Support Yamaha FJR Motorcycle Forum:
charismaticmegafauna
Well-known member
These have been used in a few instrances in the last few years to address driveability issues. The pulley that the throttle cables are attached to is *cam* shaped as opposed to circular -- in order to give non-linear throttle operation. If, for instance, your engine has a big low-speed torque spike; then, a *slower* cam on the throttle pulley will help even it out.
ionbeam
2 FUN
Yamaha is calling it a cam (hint, hint). Probably something like an elliptical wheel where the throttle cables attaches to the throttle body throttle-plate linkage. In all current models the wheel is round, delivering uniform (linear) travel and pressure.
Alan
Alan
I expect they've only changed the shape of the throttle valve cam wheel that the throttle cables actuate. If the radius of the cam wheel is increased you'd have to turn the throttle grip more (more degrees of turn) to get the same throttle valve operation as now. But, with this larger radius the mechanical advantage would increase and throttle effort at the grip would decrease.
Throttle Work = wrist force x grip rotation (degrees)
The larger radius cam wheel = increased grip rotation
If throttle work remains the same (throttle springs unchanged) then the required wrist force decreases with the increase in grip rotation.
Throttle Work = wrist force x grip rotation (degrees)
The larger radius cam wheel = increased grip rotation
If throttle work remains the same (throttle springs unchanged) then the required wrist force decreases with the increase in grip rotation.
BrunDog
Well-known member
They have changed the butterfly-side pulley as part of the whole FI system.
-BD
-BD
Probably like the Nautilus cam- starts easy, gets hard. Right?
Dangerous Dave
The older I get, the faster I was...
Hmmmmm, I would think it would be MUCH easier to make the mod at the throttle sleeve, rather than the TB end. There was a mod on the R1 forum where guys were putting part of a zip-tie in the groove in the throttle sleeve where the cable rides to fatten up the cam, thereby making it resemble a 1/4 turn throttle. I made a similar mod to my Derbi using a piece of solder in the groove of the throttle sleeve cam, under the cable. Really easy and makes quite a difference. It's gotta be easier (and cheaper) for them to change that ratio at the throttle sleeve than at the TB link. That would be a cheap and easy retrofit too.
BrunDog
Well-known member
No way.
-BD
Dangerous Dave
The older I get, the faster I was...
Because.....................................????
Bustanut joker
Well-known member
Hey isn't that the way it's supposed to happen?
Ah crap wrong web site :bleh:
BrunDog
Well-known member
There is no room inside the throttle side to make a various radius pulley (either larger or smaller pulley). There is plenty of room on the butterfly rod.
I'd bet $$ and eat my shoe if I were wrong. Hey, it's happened here plenty of times... (that I had to eat my shoe).
-BD
