Honda 400EX 99-12 Fan kit this is a bolt on plug in and go kit that moves 342 CFM of air. You do have to trim the guard between the fuel tank and engine in the very front by the stearing stem to clear

Rear Chain Guide. TRX400. - NOT AVAILABLE AT THIS TIME. However, IF you have put the 2004-2005 TRX450 conversions on your TRX400 then please see 2004-2005 TRX450 Rear Chain Guide.