2008 YZ450F Questions

27 replies to this topic
  • Joe_Jet

Posted December 13, 2007 - 07:22 PM


I run the 14/52 on my 07. Didnt notice a difference as the ratio is the same, but it should last longer. The 14 combo causes greater inertia in the drive system, but I dont really notice it?! Also, replaced the stock air filter cage with one from a YZ250, no screen. Adds more low end, but not as noticeable as on a 250F so not totally necessary.

  • bingslee

Posted December 13, 2007 - 08:29 PM


should work this time, the photos of my new 08 yz450f are at this link

  • bingslee

Posted December 13, 2007 - 08:33 PM


click this and they come up

  • Wes Woodin

Posted December 29, 2007 - 08:43 PM


click this and they come up

Would like to see the other side of the pipe! Awesome looking bike though. How do you like the pipe. How did it fit? Everything line up?

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • ncmountainman

Posted December 30, 2007 - 08:14 AM


Wanting to buy a pipe for this bike. 08 YZ450F. I was going to go with a Dr. D or a pro circuit GP4 Ti complete system. What do you guys think? Jetting as well? Also what was the concensus on taking out the screen on the filter and going with a twin air filter. I've heard that the fire resistant foam was more restrictive then the standard two stage filter with screen.

i believe the backfire resistant filter is more restrictive. awhile back i eperimented with screen removal and got the resistant one,then noticed it didn't really make much difference unless i used the regular twinair without the screen,with that combination there was a noticeable difference in snap off the bottom but as soon as you put on the resistant one without the screen it felt the same as before. well i didn't want to burn it down so it went back together with the screen and reg filter, and then down the road that filter was developing some small tears and i just replaced it with the resistant version(leaving the screen in)...well i never realized until recently that this was screwing up my jetting,the bike was running way too rich for the the way too lean jets i was using....changed back to a new reg twinair and then its way too lean(as it should be)with the same jetting. it went from a 42 to 45 pj and starts much better. so as minute a difference as it might be it sure screwed me up for awhile. anyway,i feel much safer running the screen; just don't do it in combo with the backfire resistant filter....it'll mess with your brain(and in my case there isn't much left to spare:busted: )

  • Wes Woodin

Posted December 30, 2007 - 08:19 AM


[/QUOTE](and in my case there isn't much left to spare:busted: )[/QUOTE]
Meeee Toooooo! haha! Happy New Year Bob.

  • jh0217625

Posted April 05, 2014 - 07:19 PM


Hey guys can i get some jetting advise for a 2008 yz450f with a full Yoshi RS-2 exhaust. I ride at sea level to 4,000 feet here in Socal. Need to know what main jet, pilot jet, and needle you are using along with needle clip position. thanks

  • grayracer513

Posted April 06, 2014 - 04:19 PM


Read:    http://www.thumperta...tting-database/

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