Hi,

was wondeing if anybody else had this problem, we have a 2004 Honda fourtrax 90 , the little machine is a tough one to get warmed up and takes about 10-15 minutes of driving to get to the point where it doesn't just quit.

At this time we get it started and my son keeps the throttle high rev, but he'll back down and back to the pull start we go... I start it with the choke all the way up (or on) and then try to back it off gradually, but it gets old because the choke doesn't seem to help all that much - still need to keep it at high idle or it quits.

Is there an answer to this extended warm up time, is there an adjustment we could make?

Than you,

Phil

 

Start by checking the setting on the mixture screw. Going out is richer, and all it might need is a 1/4 turn. Slowly turn the mixture screw in, counting the number of turns, until it lightly seats on the bottom. Im thinking it should be in the 1 3/4 turn out from the bottom, or so.

If it doesnt help. then the pilot jet could be partially blocked. The float bowl has to come off, and pull the pilot jet out, and the inside diameter needs to be clean and open all the way thru.

How long has it been since the valve clearance has been checked? Especially the intake side, the clearance may be too little, or actually none. That would make for poor running when cold.

Hows the idle speed when warm, about 1400 rpm? Steady, and clean sounding?

 

10 to 15 minutes sounds a little extreme, but the TRX90 is a very cold blooded machine. Ours is stock and you have to really nurse the throttle for the first 2 to 5 minutes.

Jaybee

 

Hondabuster and jaybee - thanks for the prompt replies.

The valve clearence - I have no idea, I bought it used this fall. The idle screw... I will try turning it all the way in and then out as you said (counting the turns) and then 1 3/4 out from the bottom.

I can pull the float bowl off the carb - the bottom correct? Is the pilot jet in the float bowl area? do I need to pull anything elase or when I pull the bowl will the jet come out easily? Not sure how difficult it is to pull the carb off? Our old eton 50 needed the carb cleaned about twice/season. I can shoot some comressed air up into the carb once the bowl is off - Is this how you'd recommend cleaning the pilot jet? - sorry for the dumb questions but I'm really not sure what to find in the float bowl besides floats - the pilot should remain intact correct?

I believe it was never back to the dealer - it is 100% stock so the valves probably never been adjusted. Is this something the dealer needs to do or is it a do-it-yourselfer?

Jaybee - we're also stock with this trx and yeah it needs to be nursed as well but 15 minutes is not an exageration - maybe even longer because he keeping stalling out there if he's not on the gas to keep it running.

Although when it's warm it runs perfect!

Thanks,

Phil

 

If youre gonna keep it...it might be worth the 24 bucks for a service manual, itll step you thru all the maintance and service repairs. Check ebay for used ones, sometimes there are some real deals on that kind of stuff.

The idle speed screw and the mixture screw are two differnt screws, one controls the fuel mixture, the other controls the rpm.

If you look here
ronnies
#20 is the pilot jet. #5 is the mixture screw, and #7 is the idle screw.

If the link doesnt work, go up to the top of the page, and click on the ronnies ad. Go to atv parts, honda, 2004, then trx90. Once that opens up, go to the carb diagram.

If youre somewhat mechanical, and it sounds like you are, the valve adjustment isnt very difficult. I dont have the specifics for that one, but basicly you line up a timing mark on the flywheel, and then check with a feeler gauge the clearance between the stem and the rocker. Theres a screw and locknut on the rocker for adjusting the clearance. If you get the service manual, itll give the exact steps to take , and what to look for.

This is a totally stock machine? Is the air box lid on?
Also while youre there looking over things, check the intake bolts and make sure they are snug.

 

I just did a 2004 TRX90 top end rebuild. Valves set perfect as well as timing. Just finished up with the carb adjustments. Stock Main Jet, 45 Pilot jet, air screw 1-3/4 out then adjusted the throttle screw and idles like a dream