2006-2012 Honda TRX90 TRX90EX/X Service Manual, Page 46Get this manual
MAINTENANCE
ENGINE IDLE SPEED
NOTE Inspect and adjust idle speed after all other engine maintenance items have been performed and are within specifications The engine must be warm for accurate adjustmentTen minutes of stop-and-go riding is suffi cientWarm up the enginesh ift the transmission into neutral and place the vehicle on level surfaceConnect tachometerCheck the idle speed and adjust by turning the throttl stop screw as requ ired
IDLE SPEED: 1,600 100 rpm (min')
SECONDARY AIR SUPPLY SYSTEM (U .S.Atype only)
The secondary air supply system introduces fil tered air into exhaust gases in the exhaust portThe secondary air is drawn into the exhaust port whenever there is negative pressure pulse in the exhaust systemThis charged secondary air promotes burning of the unburned exhaust gases and changes considerable amount of hydrocarbans and carbon monoxide into relatively harmless carbon dioxide and waterRemove the air cleaner housing cover (page 3-5)Remove the sub-air cleanerWash the sub-air cleaner in non-flammable or high flash point sol vent, and let it dry tho roug hly