hard to start when cold

I have a 2008 yz 450f and i went to race last weekend and i had one hell of a time starting it. I finally got it started but poping it and yes i do have some work done to it.:bonk:

What size pilot jet are you using?

stock jet but with a ti4 full system

also i have the wing,pc vent system boysen accel pump cover, and twin air filter

I'm having the same problem with my Kawi... need to go up one size in the pilot and adjust the fiel mixture screw accordingly and should be good to go:ride:

ok i will try that out but does it lean it out

check out the stickie at the top of the jetting forum about confirming pilot circuit

I have a 2008 yz 450f and i went to race last weekend and i had one hell of a time starting it. I finally got it started but poping it and yes i do have some work done to it.:bonk:

How cold is cold??? Lots of 4-strokes are cranky starting when its real cold...like near freezing tempatures. Usualy richer jetting and a hotter plug are the cure.

well i did a race last sunday at sdr raceway and the bike was a solid peice of ice from the frezzing rain in belden NY

well i did a race last sunday at sdr raceway and the bike was a solid peice of ice from the frezzing rain in belden NY

WOW thats insane:crazy:, ya talk about commitment lol...now back to topic:ride:

ya i will try the fuel air mix screww

ya i will try the fuel air mix screww

What are you at on the mixture screw now? Do u have a "quick adjust" screw or oem screw? You dont want to go too far out on turns cause they can fall out

i think it is a stock setting and it is a stock screww

YZ450's tend to be jetted on the lean side anyway, and with the cold weather, starting will be harder. As evidenced by the excessive popping you hear in the exhaust (a little is normal), the pilot jet is too lean for the weather. Go up to a 48 until things warm up again. Get a good aftermarket fuel screw, or a screwdriver that allows you to adjust the stock one and read "How to Confirm your Pilot Setting", under fuel systems in the Common Threads Sticky.

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