alright i have an lt 500r stock with stock carb and stock jets not bored with new gaskets pretty much all around. When i run my quad for a period of time at high speed (like blasting down full throttle on a straight away) or increase my throttle idle screw so that the bike idles, after it warms up i rev it high. With both of these i will frequently stay at a high rpm let's say 2000 when i idle at let's say 800. i have even tried a different mikuni that was bored to 40mm and still the same thing. Now when i switched carbs i reused the throttle idle screw. Now there are only two ways to get this to come down i can lower the throttle idle screw in which case i have to lower to the point where i will not idle anymore, or i can keep the bike in gear and manually slow the engin down with the brake. Now keep in mind that the high rev does not happen on it's own i have to take the bike up that high. Please any help would be greatly appreciated

Now i also have a keihin carb which i might switch to. 2 questions do i need a new throttle cable and do i need some type of spacer because the carb is 9mm shorter

 

you have an air leak somewhere probably or the cable is kinked somewhere . a stock cable wont be the right legth for a khien carb . might check to see if the carb cap is on tight also .

 

but lowereing the idle screw will stop the air leak or unkink the cable that's what i can't understand
thanks for the help so far anymore ideas

 

also where can i get a cable and what kind

 

You have an air leak.You said it only does it when its warm,well metal expands and contracts with heat and cold.So it will act diferently at cold/hot temps. There are tons of places you could ghave air leaks.The reason the idle screw will help is because your changing your fuel air mixture when you turn it in or out. You have an air leak and you are compensating for the air leak by changing your idle screw. I would take it to a good shop and have them do a pressure test or leak down check for air leaks

 

You may not have a bad gasket or seal,The problem might be with your carb but when it is warm you are getting to much air or air and fuel

 

thats what i was trying to say but didnt come across that way . LOL thanks super !

 

Yep, you guys are right... a lean condition will make the high idle situation squall is describing.. It's either an air leak (Do a leak-down test) or jetting... but since you've changed carbs, that's a bit unlikely... unless you used the same jets. Anytime a motor is cracked open, it should have a leak-down test performed... One little leak can spell catastrophy = lean = kaboom...

Good luck!

 

thanks alot guys i will do a leak down test as soon as i can and will post the results thanks alot again