How mush better is the 426 engine vs the 400

How is the power at low rpm is it okey or do you have to rev it alot??

Bottom end on my '99 400 is good (with aftermarket exhaust). We were chugging up some wicked steep climbs in Moab, Utah with nary a hitch, no stalls.


'99 WZ with all YZ mods, FMF PowerBomb header, Stroker SX-1 silencer, SS front brake line, forked over by Pro-Action, OEM YZ tank and IMS seat.


how did you get on with your exhaust combo?

noise level, quality, fit, power etc?

what happened to that carbon airbox?



The exhaust fits great and quality is excellent. Noise is a very good compromise w/ the power. I did lose bottom end from open end exhaust to my new setup. Please note my jetting is still hosed though. Using the wrong microfiche (2000 YZ), I ordered & installed a DTM needle instead of the DVP. I do have substantial backfiring on closed throttle deceleration and have to mess with the fuel screw some more. We are knee deep in snow here and the bike is parked for the duration. Air box is installed. I still have to do the first teardown since it's installation. I am curious about the dirt infiltration through the carbon fibre. It sure looks pretty though (pretty expensive?).

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