2007 trx450r jetting

[Rob001313]

I have a 2007 TRX450r with HMF sport series pipe, K&N filter and no airbox lid. The pipe came with a 165 main jet but, there is no way this combintion of parts will work without a small jet and needle adjustment. My YFZ450 ran way too lean without more than a main jet adjustment. I am at sea level and could use some hints.

[Mike/HMF]

You are right we recommend stepping the pilot up to a 48 from the stock 42. We also found that a #55 leak jet nearly eliminates the bog sometimes experienced with the newer FCR carbs. We found the 07 and 08 needles to work good. We sell a needle for the 06 models because they will run lean without a fatter one.

[ewolak]

i've gotta 07 with a hmf GT thunder exhaust,rev box,K&N filter with no lid an accelerator pump cover #55 leak and a 190 main jet a stock pilot and didnt touch the needle or the screw it runs awsome and is super fast the only thing is a real quick shot on the throttle from dead idle and it dies theres also a littl bit of a crackle at high rpms what should i change or add

[Mike/HMF]

Definitely wanna get a 48 pilot in there to start. Also get an easy adjust fuel screw and adjust it to the highest smooth Idle. If you still have the bog when you stab the throttle you may need to adjust the accelerator pump timing.

[ewolak]

so the fuel adjust screw i turn it to more open its more fuel but it idles great for some reason should i change the pilot and see what happens and should i bring the main jet down to like a 170 i'm at a high altitude and how do you adjust the accelerator pump timing

[Mike/HMF]

What is your elevation? Use this chart --> http://hmfengineering.com/forums/showthread.php?t=1957 to calculate what main to use. If you are under 3500 feet use the 48 Pilot. Anything over that use a 45 pilot jet. Once you have installed the pilot and main jets and you have the machine idling at operating temp, turn the fuel screw in until you start to feel resistance, then turn it out until you reach your highest smooth idle. If it seems high, use your idle knob to back it down to your liking.

[ewolak]

ok my elevation is around 1300 ft. so i should deffinatley go with a smaller main would the 165 work i was also looking at alba's setting too but i'm not using their pipe

[Mike/HMF]

165 main, 48 PJ. No lid. Also here is a link to the accelerator pump timing adjustment. --> http://hmfengineering.com/forums/showthread.php?t=1310