Idle problems!!!!!!

[Ric250X]

I just finish doin a tune up on my 87 honda 250x and whenever i get to kick start the quad it ran for a second and then shuts off.I got the quad running again and this time i was giving gas but it had a sound like a pop tone.If i let it idle it will shut off.There's a knob underneath of the TB and there's a flat head screw next to it.What are they for?Can someone help me to get my quad to idle right?Thanx

BTW How can i tight the chain?Cus is kind of loose
Rick

[JoE4554]

I dont have any advice for the idle problem. Though for the loose chain. On the axle carrier , theirs this thing on the left side next to the sprocket that you turn to back to tighten.

[YFZ450Ridr]

turn that black knob clockwise a little, mabye a lot in your case. just give it a 1/4 turn and then give it some gas, and see how it does and then go from there.

dont make your chain too tight, you want about an inch of plaw up and down. have somebody a little heavy sit on the grab bar, if the chain is completly tight and cant move, then its too tight.

[Ric250X]

Thanx guys.