YFZ 450 options

[smeese]

Sorry I am sure we have a lot of 4X4's on here, Anyone meddle with the quad style ATV's? Looking for some Jet/Intake/Exhaust options that have worked for you. I am currently running a regular sponge air filter and had it Jetted for that along with the FMF pipe....It runs pretty good now but seems like it should have better throttle response. Sometimes it Grunts like it wants to go then takes off.....am I running too rich on the Air/fuel ratio? Should have gone EFI

[Dave S]

Your spark plug will give you a better idea of how it's running (rich or lean). There's been a few options for the YFZ to increase performance on the carbed models. Although it's going to mean even more maintenance on an already high maint. machine, some have made air box mods or remove the air box cover in an attempt to improve air flow to the carb. You'll have to upgrade to a better filter system than what you have and clean it religiously.

Another option to look into for more performance is retarding the exhaust cam 1 tooth. The YFZ 450 quad has the same set up as the WR450F. If you retard the exhaust cam by 1 tooth, it gives you the same as the YZ450F bike with a higher mid range and top end. Although since you mentioned it's kind of sluggish, I wonder fi this hasn't already been done.