Jetting Question

[fox945]

I have a 05' TRX450R with a FMF Factory 4 slip-on with the FMF power bomb header, K&N air filter with pre-filter w/out air box lid. I bought an FMF jet kit but don't like the way it seems to run. I've seen people recommend jetsrus.com and looking to just buy just the size I need instead of a whole kit. I live in eastern TN which is kinda mountainous. I was thinking of buying a 170, 175, & 180(getting 3 just for temperature changes) main jets and going up one size in the slow jet from 48 to 50. Does this sound about right for my setup?

[WilRideAnything]

The main would be between a 180 and 185. The pilot jet is correct. Plus move the needle up on notch.

[fox945]

Should I just keep using the needle that came with my jet kit originally or use the stock needle?

[d3ktrix]

What jets are in there now and in what way is it not running right?

[fox945]

I'm pretty sure the jet kit recommended the 165 main w/out air box lid but don't know if the size is the same as it would be for different brands. It doesn't like to run when its cold and also it pops and cracks on decel, Also when the engine is warm and you lay into the throttle it hestitates some. Figure going up one for the slow jet would fix some of my problems but thinking it needs a bigger main jet as well.

(oh as of right now it has the factory slow jet)

[exrider12]

try the slow jet. seems lean to me

[d3ktrix]

lol everything is lean. Your using the recommended jetting for an 06+ 450R with an FCR carb.
The 04-05 bikes with a stock carb require much richer jetting.

Hope you didn't ride it too much like that, probably running super hot.

Try the following
185MJ
50 Pilot
HRC needle middle clip
adjust A/F screw accordingly

Much closer starting point then what you have in there now. Then tune it from there

What is the elevation like in your area?
Higher elevation might require 1 or 2 main jet sizes smaller.
Colder temps will require richer jetting.

[fox945]

I guess its a good thing its been cold weather since I rejetted it. Appreciate the info. I'm currently at about 1k ft above sea level but I do a lot of riding around 2k -2.5k above.

Also does anybody know where to get a custom fuel screw that makes it easier to adjust while running.

[d3ktrix]

Actually the colder air was working against u making the bike run even leaner.

When you ride in those higher elevations you will probably need to drop the main jet one size.