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fultz416ex
06-19-2008, 11:08 AM
i put a lexx pipe on my 05 450r. i did not re-jet yet. i have the airbox lid on and i was told it has the HRC cam in it. i just changed the coolant and put a 14 tooth front sprocket on it and took it out for a little spin. it was hard to start at first and when i was riding it, it seems to have a flat spot thru 1st gear. could it be the jetting? maybe adjust the fuel screw out a little? any ideas? thanks
06-19-2008, 11:36 AM
Adjusting the air/fuel screw will help the starting issue. Do you know what main jet is in there now? I was running a 150 main with a hmf slip-on and a closed lid on my 04.
represent618
06-19-2008, 11:58 AM
sounds like you ned more fuel and less air?

if yo roll it on easy, is ther still a flat spot, or only if you dump the throttle quick?
fultz416ex
06-19-2008, 12:23 PM
either way there is a flat spot down low. i took it out on the road and opened it up and it seems to run fine up top, just down low it doesn't hit as hard as it should, which is where i need it most for XC.
400exrider707
06-19-2008, 12:51 PM
If you have a pipe and HRC cam, and haven't jetted it, it isn't running fine anywhere. You need to rejet this thing!
fultz416ex
06-19-2008, 01:12 PM
i don't know what size jets are in it now. what do you recomend?
warr72
06-19-2008, 04:20 PM
Rejet just went through same headache with my 08
fultz416ex
06-20-2008, 10:13 AM
well i pulled the main out and it ws only a 118. i had a 180 from my last 450 so i put that in and opened up my airbox. hope this works.
06-20-2008, 11:00 AM
Other than raising the needle up one notch you should be OK.
warr72
06-21-2008, 11:44 PM
I agree check needle position. ;)
fultz416ex
06-26-2008, 01:28 PM
do i access the needle thru the main jet location on a 05 carb?
06-26-2008, 01:31 PM
No you get it from the top. You remove the top cover. Under there is the arm that the needle is bolted to. There are 2 small phillips screws. You take them out and then you lift the needle out. Move the clip down one notch. That will raise the needle.
Good Luck
fultz416ex
07-04-2008, 09:54 PM
well i adjusted the needle like everybody said. it runs good but when i was riding today, coming down hills and riding in the woods with the clutch pulled in and when i let it out at low rpm it wants to stall. where do i go now with the jetting? can i just turn the idle up or the fuel screw? thanks
fultz416ex
07-07-2008, 12:16 PM
one of my friends told me to turn my fuel screw in because it sounds rich down low. i turned in the screw a 1/2 turn. think this should do it?
venom450r
07-07-2008, 06:48 PM
Your fuel screw will only affect idle to maybe 1/4 throttle. You need to check what jets are in it and go from there. Nobody will be able to tell you exactly what jets to run due to there being so many deciding factors (elevation, temp, mods...).
This link (http://www.thumperfaq.com/fuel_screw.htm) should be able to help you out a good bit though.