Check the listing for details. Honda Big Bore 440 TRX400EX trx440 trx sportrax carburetor multi stage jet kit. Condition: New. Listed at 35.04 USD. This Jet Kit Fits 99-08 Honda TRX440EX Sportrax ATV ((( trx400ex THAT HAS HAD THE BIG BORE 440 CYLINDER KIT INSTALLED ))) MultiStage / You get What's In Photo. Select the appropriate stage needed. Modifications to the air intake and/or Exhaust system to your ATV will change the air/fuel mixture to your carburetors causing a lean running condition. These kits include 2 Pilot Jet ( #42 #45 ), 5 Main Jets ( #170 #172 #175 #178 #180 ) and two needle shims for your carburetor. Multi Stage is for those experimenting with different engine, air intake and exhaust systems Modifications to the air intake and/or Exhaust system to your ATV will change the air/fuel mixture to your carburetors causing a lean running condition. Jet Kits will compensate for the lean running condition. Lean running conditions can destroy your engine and decreases overall performance. Jet kits are easy to install but does require some basic carburetor tuning knowledge. Refer to your shop manual for carburetor removal and jet installation.