250sx idles high

[J trike]

I find the idle tends to creep up a little high on my 85 250 sx once it has warmed up and been ridden a while, making for hard shifts.
I ordered a carb kit and bought some carb cleaner but I'm hesitant to do the kit as it is otherwise running great.
Could it be just an idle screw adjustment or the float maybe dirty?
Thanks

[jerkin]

Before I went too far I'd get a can of carb cleaner, warm it up to where it's idling fast then start spraying the carb and intake with the carb spray. If you have an air leak you'll hear the rpm change. I've never caught one on fire but watch spraying around a hot exhaust.

[ps2fixer]

Another thing that can bump your idle up is the cable route, if it isn't ran the factory way when you turn the handle bars it will give it a little gas.

Carb rebuilt kit wouldn't hurt anything, you can always keep your old parts around incase it does nothing and you know the parts were not at fault. Generally I try cleaning the carb before buying rebuilt kits, since a dirty jet can be cleaned, a worn jet has to be replaced.

Also check your choke cable, it opens a port for another jet and can throw off the idle a bit.

Just to point out, there will be a little bit of an idle change from cold to warm, but shouldn't be extreme. This is why carb adjustments should be done at full operating temp including setting the idle.

[J trike]

Ok so I took the air filter and air box out to access the carb. I had run it for a few minutes prior to warm it up. I start it up and when it starts to idle high I spray in some carb cleaner and she just about stalls.
Then she starts all over again to rev up and I spray some more.
I've done this a half dozen times but she seems to rev higher than ever??

Is it because the air box is out that it should do this? I'm waiting to reassemble it until someone can let me know if I should continue to remove the carb and change the orings/gasket.
My experience with these things is minimal but I'm determined to learn!
Thanks

[shovelryder]

Spray the OUTSIDE of the carb and intake to check for idle change.

[J trike]

I tried that the other day but I'll try again.
This stuff is called gum out and says to spray in and around butterfly to remove deposits so that's what I understood.

[shovelryder]

I tried that the other day but I'll try again.
This stuff is called gum out and says to spray in and around butterfly to remove deposits so that's what I understood.

Yes....it's carb cleaner and the can will say to spray the inside. But since it combustible we use it to find intake leaks on the outside. Soak all the way from the cyl head, all around the boot, and around the carb. If the idle changes ya found the leak.

[J trike]

Today I soaked all of the outer carb/ boot areas and nothing seemed to change the high idle when in neutral.
If I hop on I apply a little choke to slow the rpm and when in gear it seems much better than when in neutral.
Should I try the carb kit next I guess

[Jmoozy27]

Your mixture is rich at idle. I would turn the screw in about a quarter turn and see where it gets you. Is the air filter dirty or old? If so then you should replace it. Do you have to choke it to start it while cold? Could possibly be choke.

[J trike]

Definitely needs choke held and stubborn when cold. I keep it in a fairly warm garage right now but left it out a few hours once and noticed it was temperamental.
My air filter looks very clean and fairly new.
As far as choke goes I tried to buy a new choke lever because it won't hold quite right but found they are no longer available.
I had just replaced choke lever on 85 big red and it now works great but am told they are different

[n8r]

Mine does this too, time to check for leaks

[250sxx]

My 1985 250 SX does the same, I just lower the idle once I did a few mins of riding, idle screw is easy to reach, even when sitting on trike u can reach. Engine won't fully warm up just by idling in driveway. Choke jet on mine was clogged up pretty good when I acquired the trike this fall, used a very small wire brush to free the jet up, then added some seafoam to a full tank of fresh gaz, and voilà.

Mine too was a pita to start up when cold, but since I freed up starter jet, engine starts right up.

Good luck

[Flyingw]

This is what you need.

http://www.3wheelerworld.com/showthr...54#post1257154

[J trike]

Well I simply turned the idle screw counter clockwise in total about a half turn and it seems much better.
As far as the cold start tutorial goes ..wow!! Pretty knowledgeable guy.
I think I may just turn the heat up in my garage ! Lol