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  • Jim_Patterson

Posted February 01, 2003 - 09:26 AM


First, the bike was #896 produced.

Regarding flywheel nut torque I did not loosen, then retighten, I just wanted to see if it was set at 47. I Engaged 5th gear stepped on brake and started wrenching, ah it takes more brake pressure than I thought, lay some more on. More brake, more wrench. Bingo 47# wrench clicked just about on the money.

Next jetting. I did most all the things you suggested plus remove the tank and rotated the head pipe clamp out of the way a little bit more. With bark busters on, I had to open up the throttle halves, disconnect the inner cables from the throttle body so I could get the carb to turn enough. I changed 2 of the 3 jets (main & pilot) as suggested by UTVOLS. Stock main 150, new main 160. Stock pilot 45, new pilot 48. I didn’t change the starter jet. Put it all together and I just had to start it and ride it. Started very easy on choke and choked RPM dropped down from the very high rev that it did before jetting, to a more reasonable rev level. Slight warm up, now on idle, some adjustments, and the idle hunting it did before and mini backfiring was gone. Took it on sub side streets (they were wet and or slushy) and it ran very good. I think it will need a bit more work. It MAY need work in 1/8 to ¼ area, but it feels so much improved I won’t change anything until I can be sure what it needs if anything.

Throttle stop info.

2003 YZ450 TS overall length 7/8 inch. Head measures 3/16, shaft behind head 11/16 plus 1/32.. minus 0
PN 5jg 14591 00.


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