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Noobie question on setting A/F, idle, etc. on 06 TRX400

1999 Views 9 Replies 3 Participants Last post by  retro
I wrote a huge novel then deleted it. I think most of you don't want to read all that, so I'll get straight to the point:

Stock exhaust. New oiled UNI filter, new plug, fresh oil. New throttle stop cable (it was broken when got bike used). Sea level to 2500 feet max riding. Went from stock jet 38/148 to 42/152. Desire better starts cold and less stalling while cold. Runs real well once warmed up fully.

1. The throttle stop piece that threads in to the bottom of the carberator, only barely touches the wheel (that the cable attaches to), in the last 2-3 turns over the knob (before spring is fully compressed). Does this sound right, or should I have a little more slack so I can thread the screw out and have more control? If so, the only idea I have is to loosen the throttle a bit from the other side (by your hand) so the wheel drops down more? It seems that the wheel has a big spring behind it anyhow to cause the throttle to go back to none, right? So if the throttle cable was longer (by loosening at the hand throttle area??) it would drop a little, and lower the idle??

2. When starting the bike with a freshly cleaned carb and larger pilot jet it idles so high. I don't have the #, but it sounds at least 2000 or more. It for sure isn't stalling on me like before, barely putting along. Is the idle simply controlled with the throttle stop cable and the throttle adjust on the right side? Is there any other spot on the bike that this is controlled?

3. The A/F screw. I knew I needed a "D" socket, which I didnt have yet (Motion Pro tool arrives Tuesday UPS says). I tried the .22LR shell method with one side pushed down. total PITA, so I will wait... I watched videos online and read a lot and people give various approaches. What do I do here? Assume it is totally wrong. How about screw it in all the way (without hard bottoming out), then 2 or 2.5 turns out, start the bike and see? If it sounds like its bogging, another 1/4 or 1/2 turn till it sounds good? Then see if another 1/2 turn makes no difference in audio, then back to the original area? Do I do this cold, or let the bike idle up and get really warm? I can't ride it around here (the burbs, no area), but can for sure idle it and even maybe ride it a little in my cul-de-sac 1-2nd gear.

I really am not sure how the A/F adjustment is properly done. I did see about a plug chop, which I am fine doing, but at least want to try to get it in the right area.

4. I see talk about setting RPM. How do you do that? Is there a cheap tool I can use to set it? Maybe an iPhone app that can decipher the noise of the engine and determine RPM? If not, what do you buy to get an RPM reading? Is it simply a tuned ear?

Anything else I should know? This is all in prep for the fall/winter so I can take this out to the desert and know it'll start right now. The wife will probably right it most of the time as I'm on my dirt bike and I want this thing tip-top for her. I cant afford any reason for her to say "I hate riding these things"
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Thanks for following up and letting us know how you fixed it!!!

You shouldn't let that Honda dealer get away with selling you china made jets and lying to you about it... get all of your money back. Liars & thieves get no mercy.

Have fun with the 400!
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