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That is the best and most indepth infromation that i have heard yet! thanks the info is greatly appreciated, what kind of slip on was that? head pipe? once again thanks for the info, thats been the most useful thing that i have heard yet!thanks!
 

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Discussion Starter #5
do you know the jetting specs for removing the spark arrestor and air box lid?
165 main, 3 turns out on the idle mixture screw, and #5 clip position. This is only preliminary. I have been in contact with one source that is testing a differant needle. I will let you know if this works out.

LS
 

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LS,
Just to clairify the only difference in the WR and YZ cam is the location of the Decompression pin (lobe hight and durations are the same). The WR has a smaller batter with less amps that is why the WR won't start (by the starter moter) if you change the timing. The YFZ has a bigger battery which spins the motor faster so you can start with the modified timing.
 

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LS,
You said that your running the pilot screw at 3 turns out?? Ive always been told that the FCR carb shouldnt be run with the screw any farther than 2 turns out.
Have you tried going to a higher pilot air jet??? I think the YFZ450 uses a 42 PAJ for stock.
Also, on your clip position, are you numbering your grooves 1-7 from the top being #1 and the on closest to the taper being #7????
 

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Discussion Starter #9
LS,
You said that your running the pilot screw at 3 turns out?? Ive always been told that the FCR carb shouldnt be run with the screw any farther than 2 turns out.
Have you tried going to a higher pilot air jet??? I think the YFZ450 uses a 42 PAJ for stock.
Also, on your clip position, are you numbering your grooves 1-7 from the top being #1 and the on closest to the taper being #7????
I have run up to 4 turns out with no problem on the old FCRs. I will be using a larger pilot jet as soon as I get one. Pilot air jet - I will only change after testing shows that it needs it. #5 clip position is as per Keihin with #1 starting at the top.

LS
 

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Thanks LS,
I was just curious about the pilot jet. Ive always heard 2 turns max, it even says it on there web site, but the YFZ came from the factory at 2 1/8???? (or atleast mine did). Im fairly new to the FCR, so Im just trying to get as much info on it as possible.

Also, who makes the torque silencer you are using????

Thanks for the great info by the way!!!!!!!
 

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Discussion Starter #11
Thanks LS,

Also, who makes the torque silencer you are using????

!!!!!![/quote

It is a prototype. I have been talking to one company that may build it. If they choose not to, I will post the dimensions for any one to see. As it looks now it will be available within 2 weeks if the production unit performs to the prototype specs.

LS
 

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It is a prototype. I have been talking to one company that may build it. If they choose not to, I will post the dimensions for any one to see. As it looks now it will be available within 2 weeks if the production unit performs to the prototype specs.

LS
What would be the difference in a torque silencer and any other aftermarket silencer?
 

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http://www.gtthunder.com/YfzDyno8.html

Laz,
On the above Dyno you had the cam mod, airbox lid off and the HMF full system? And your jetting was 170 main 5th clip on the needle any mixture adjustment? You mentioned earlier in this post that you were at 3 turns out but that was with a 165 main.
I am just making sure because I am picking my YFZ up on Saturday and I am going to do all the mods before I even ride it.
Isaac
 
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