Can somebody please confirm my pilot

I seem to be mystified a bit, it just might be me being paranoid, I have a 06 525 exc, outside temps have beem 75f-83f, humid today, at night its a crap shoot it can be 55f-68f, I ride at 400ft to 3000ft, the first pilot was a 42, bike starts no choke, when setting fuel screw at operating temp the highest smooth running was at 1/4 turn out to closed, dropped to 40, the highest smooth running was 1/2 turn out, I dropped to a 38, the highest smooth running is now at 1 1/4 turns out today 80f and humid, Im assuming when it cools down I may turn screw out a little more, Im just worried about the 38 jet, or maybe I should take some meds for paranoia.



Lets first assume everthing on your bike is in good condition.

Pilot spotless, Choke and hot start good, No vacuum leaks, Yadadadda

Fuel Screw/Pilot Jet

Fuel screw settings in the 'book' are recommended starting points. Every bike is different, as is the temp and altitude. Set the screw according to this method. Do it with the bike fully heated up.

Gently turn the screw all the way in. Now back it out two turns. Start the bike and fully warm it up, go for a 10 minute ride. Set the idle to speed to 1,500~1,800 RPM as best you can (I know, without a tach this is tough, just set it to were it idles relatively smoothly). Once warmed, slow the idle to the lowest possible speed.

*** When turning the fuel screw, keep an accurate 'count' of the amount you are turning it and record it in case you have to reset it for some reason. Makes life easier when you can just set it from notes Vs. going through the procedure again.***

Turn the screw in until the idle becomes rough or the bike stalls.

if it stalled, open the screw about 1/4 more turn. Restart it and slowly screw it in till you can just perceive a change.

If the screw can be turned all the way in and the bike still idles perfectly and does not stall, then you need to go down a size in pilot jet.

Now very slowly, open the fuel screw till the idle is smooth. Blip the throttle, let the bike return to an idle, wait say ten seconds. Confirm it is the same smooth idle.

If the screw has to be opened more than 3 turns to get a smooth idle, you need to go up a size in pilot jet.

If you find it does not stall with the larger jet but has to be open more than three turns with the smaller pilot jet, put the larger one in and set the fuel screw at 1/2 turn.

If the idle speed increased, adjust the idle speed knob to return the bike to a real slow idle speed. You must then re-visit the fuel screw. Keep doing this till the fuel screw is opened just enough to provide a nice steady idle at the lowest possible RPM. Once this is done, increase the idle speed to the normal one for your bike, typically about 1,800 rpm, but go by the spec in your manual.

Thanks for the reply Bill: everything on the bike is good condition and no vacuum leaks and I have a tach, its just that in the last while Ive been riding in cooler climates then boom hot and or humid, its the thought of dropping 2 jet sizes that had me wondering as I never had to do it yet I maintain wide range of jets and usually 3 of each as I dont clean them, I just toss them, I was under the assumption that the fuel screw should be turned out atleast 1 turn but no more then 2, I was looking for the sweet spot after turn 1, not to go past the 2nd turn.

A slight leak at the float needle seat could cause a rich condition. Not uncommon for the needle seat oring to go bad.

However, based on where you are, if you're talking about your winter to summer, that is an extreme temp change and can easily explain it.

worn needle jet and the use of aluminum fuel screws can both make the pilot circuit act rich.

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