FJR Owners Forum banner
  • Hey Everyone! Enter your bike HERE to be a part of this months Bike of the Month Challenge!
1 - 9 of 9 Posts

·
Registered
Joined
·
949 Posts
Discussion Starter · #1 ·
Just looking at the current posts in FJR Central - +7 on FI......and while some folks are adapting to a more gentle throttle control approach for the 06 to get around any low speed abruptness or snatchiness I'm wondering if the problem can be reduced with a combination of fixes. If we put aside the emission based, low speed mapping issues for the moment (ie fix what you can for lowest cost first) and focus on the mechanical and rider based issues of improved throttle control these are the fixes that come to mind for me:

(1) Develop better throttle control.........

(2) Reduce the spring based resistance by removing the unnecessary throttle return spring. This fix is well documented.

(3) Increase the throttle sensitivity by increasing the rotation range Vs cable pull. This could be achieved by using a cam twist grip / cable pull where the immediate radius of the cam is reduced from the current radius for low pull / RPM and progressively increased to full current radius at high RPM. This means that the angular / rotational throttle range is increased for low speeds which will provide more throttle sensitivity for the rider.

I don't know what the current twist grip mechanics look like, but if its a reasonablely easy matter to deepen the cable guide "recesses" or grooves etc and create your own progressive cam effect with a thin flat file then modifying the existing part may be possible as opposed to waiting for an aftermarket solution.

(4) An eccentric centred roller further along the cable assembly may also be useful but it would be necessary to ensure the roller / cam didn't slip on the cable. Similarly some sort of eccentric pivot / roller could be used at the common drive rail for the throttle body butterflies.
 

·
Registered
Joined
·
949 Posts
Discussion Starter · #3 ·
Damned if I can feel any lighter throttle on the 06 in comparision to earlier models...still feels overly heavy in standard form. Without going completely feral and tearing things apart to check on cable routing and cable friction / lubrication you would expect that the cables were lubricated and well routed by Yamaha prior to delivery .....wouldn't you? --- or is "assume" gonna make an "ass" out of "u" and "me" again.

Can someone advise on the design amendments used by Yamaha on the 06 to "lighten" the throttle action. Just what has been done? Changes in mechanicals, routing or low friction cables ?
 

·
Registered
Joined
·
949 Posts
Discussion Starter · #5 ·
Thank you for posting those links! Probably should have had a look over there before reinventing the wheel.

I absolutely agree with FredH that greater twist grip rotation range Vs length of cable pull is the key to a more sensitive throttle at lower revs. I still can't work out if Yamaha have made the throttle pull more or less cable per degree of twist grip rotation.

Installation of FredH's cam fix looks a little intense with the risk of dropping the bent wire into the rest of the mechanicals. Using hemostats ( I think they are very long, fine pincers or clamps) for the installation may put the fix - at this location - into the too hard basket for many folks. Why not go to a possibly more accessible option of modifying the throttle twist grip itself.
 

·
Registered
Joined
·
949 Posts
Discussion Starter · #7 ·
bounce said:
I'm looking forward to your write up.
There's a couple of posts on the FJRforum that have also shown some interest in a potential modification of the twist grip assembly. Hopefully someone will be motivated / have the time to look at this option more closely. I am fully committed time wise at the moment - probably the phrase "Up to my arse in alligators" best summarises the current level of committment. In short, I'm looking forward to my write up too.
 

·
Registered
Joined
·
22 Posts
lenz said:
Thank you for posting those links! Probably should have had a look over there before reinventing the wheel.

I absolutely agree with FredH that greater twist grip rotation range Vs length of cable pull is the key to a more sensitive throttle at lower revs. I still can't work out if Yamaha have made the throttle pull more or less cable per degree of twist grip rotation.

Installation of FredH's cam fix looks a little intense with the risk of dropping the bent wire into the rest of the mechanicals. Using hemostats ( I think they are very long, fine pincers or clamps) for the installation may put the fix - at this location - into the too hard basket for many folks. Why not go to a possibly more accessible option of modifying the throttle twist grip itself.
I was born with ten thumbs, each the size of a baseball bat. I was able to do the Fred H copper wire fix without any problems. I think a hemostat is a necessary tool for the procedure. While I was in there I also loosened the center throttle spring one revolution. Different motorcycle. If I can do these, ANYONE can. Take the gas tank all the way off, it's worth the two extra minutes. Helps if it's not full.

I originally tied some dental floss to the copper wire, but it broke. I didn't really need it, but had I needed to try a second time I would have used some monofilament fishing line as a safety retrieval.
 
1 - 9 of 9 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top