YFZ Central banner
1 - 9 of 9 Posts

·
Registered
Joined
·
23 Posts
Discussion Starter · #1 ·
Has anyone installed a twist throttle on the Yamaha YFZ450 yet. :D
If so, How do you deal with the TORS (Throttle Over Ride System). :(
I was told to jump the wires on the throttle. :re
Do I have to jump the wire from the Carb too?
Thanks for any information. :lol
the sooner the better, Cuz I'm headed for Buttercup on Friday the 18th of feb. If I don't get this issue figured out, I'll have to put the thumb throttle back on for this trip. :(
YFZ450's Rule!
 

·
Registered
Joined
·
1,439 Posts
First, :search works.

Easy way...
You can do like most and just cut the wires twist them together, tape and tuck it away.

Or more work...
Follow the cable down from the throttle to the wiring harness. There you will find a white connector, disconnect and remove the cable. Make a jumper wire out of two spade connectors trimmed to fit and attach to the remaining connector. I soldered mine, then wrapped the connector with electrical tape.
 

·
Registered
Joined
·
23 Posts
Discussion Starter · #3 ·
Amergin,
Thanks for the reply.
Hey, do I need to do the jumper on both the wires going to the carb and the wires gong to the thumb throttle too?
Or just the ones from the Throttle.

Cuz I jumped the wires from the throttle only and it hesitates when I twist the throttle quickly.

If it's just from the throttle, then I may still have some jetting issues from the new pipe and filter installation.
Main jet 165, stock pilot, GYT needle at 3rd notch.
 

·
Registered
Joined
·
1,439 Posts
The hesitation has nothing to do with the TORS switch. TORS is just a throttle override safety circuit. Throttle side is fine, only one end of the circuit needs to be closed.

Maybe Pahrump or one of the other jetting gurus can help you out. I believe everyone is experiencing a slight hesitation with hitting the throttle open from completely closed. Mine does but since I never ride that way it's no big deal. I mean, I don't sit on the line idling before ripping up the hill. If I did my old ATC90 would beat me up to the top...
 

·
Registered
Joined
·
23 Posts
Discussion Starter · #5 ·
Thanks for the info.

That at least eliminates the TOS problem.

I'll try to get the jetting dialed in now.

Ride safe, but not too safe.
 

·
Registered
Joined
·
416 Posts
I have done this. All I did was jumped the two wires going to the cdi, from the tors and removed the wires at the carb including the tps by gutting the wiring harness and ripping all the junk out of there, by the way, I have the kicker, so I got rid of all electric stuff, including any sensors. This was fairly easy and makes the quad a lot easier to work on for sure. I would say the stock pilot jet is killing you, try going to a 45 or 48 with fuel screw out 2 to 2.5 turns. I am unsure on that needle, but I kept my stocker in and have it on the fifth clip and have no hesitation what so ever. Hope this helps
 

·
Registered
Joined
·
5,829 Posts
Sounds like you got the TORS fixed. I installed a Twisty on mine the day I bought it, cut the wires about 12"s below the thumber splice them together, tuck them away and forget about them.

Now the jetting, try a 48 pilot and adjust your mixture screw from there to get a good idle and the low end hesitation will go away.

Adjusing the pilot and mixture screw:

When the pilot circuit is jetted properly, starting the bike should not be a problem. You will need the choke to start cold and it won't run well off of choke for 30 seconds or so. The bike should idles smoothly and have no hesitation of idle and minimal backfiring on deceleration.

Setting the Fuel Screw / Pilot Jet "by Ear"

1. Adjust the idle with the black knob until it is too fast. Then adjust it back down until it is around 1900-2000 RPM or if you don't have a tachometer (see below) until it sounds just a little high.


2. Before you start adjusting, count the turns required to tighten it up lightly.

3. Then start the bike with the slightly elevated idle and turn it out 1/4 turn, 1/2 turn, 3/4 turn and so on until you get to 2 turns. Listen for best RPM and best response to a quick 1/4 turn tweak of the throttle at each position of the fuel screw.

4. Now turn back in 1/4 turn at a time doing the same thing. By now you should have been able to distinguish the speed of the idle and the responsiveness to tweaking the throttle.

5. If it gets better between 3/4 and 2 turns out, set it at the best location and leave the rest of the pilot circuit alone.

6. If it is getting better turning it in or is best less than 3/4 turns out, replace the pilot jet with a smaller one and go through this procedure again.

7. If it is getting better as you turn it out or best at more than 2 turns out, replace the pilot jet with a larger one and go through this procedure again.




BTW remember the search button op top and left, its very powerful. :D
 

·
Registered
Joined
·
23 Posts
Discussion Starter · #8 ·
Pahrump,
Thanks for the Pilot jet and screw adjustment advice.
I think I have the 0-3/4 throttle performance up and running. 45 Pilot and Pilot screw adjusted to optimum throttle blip performance. She likes to wheelie now.

Now for the Main?
GYT recomended a 165, Results: slight missing at WFO
Popped in a 170, Results; Worse Misfires at WFO
Went back to a 160, Results: Misfire at WFO, Note, Exhaust did not get noticably red with the 160 Main.

I haven't tried the 168 Main yet which I have read is recommended. But if I am still getting misfires a WFO, do you have any suggestions? Could it be something other than Main? Thanks in advance for all helpful suggestions.

Heading to the desert tommorro, and would hate to be messing with Jets in the sand.
 

·
Registered
Joined
·
5,829 Posts
With a pipe and K&N, at about sea level which you are, most folks are having the best luck with a 170-175 main, 45/48 pilot, and the NCVQ (GYTR) needle on the 4th clip.

Of course the screw has to be adjusted last and it usually ends up at 1.5 to 2.5 turns out.

Myself I would put in a 172 main, 48 pilot, 4th clip, and set the screw to 2 turns out.

Should be close enough and run like a raped ape.
 
1 - 9 of 9 Posts
Top