Bouncing idle

[Carl Bumgardner]

I have been working on this blaster for what seems like ever
Replace the left side case, transmission, complete top end, carb ( appears to be a mikuni knock off), reed cage/intake (boyesen rad vavle) I did a leak Down test and it held 7psi for 10 minutes (until I remove the exhaust plug) stock pipe and dg silencer
It starts up and will idle but when you rev it, it will not come back down to idle like it should. It will bounce for a little while and then eventually smooth back out.
I've tried adjusting the idle screw but it didn't seem to change anything.

 

[Blaaster]

Idle speed adjusting.

Set float level, make sure that all jets are clean and fuel flows freely from the float bowl drain
when the screw is cracked open.
Start with air screw 1.5 turns out.
Set idle screw so that it has some sort of idle. With TORS it is the big screw under seat on top of
unit. With no TORS is is the brass screw midway down carb body.
Warm up motor and then set idle screw for a faster idle, 2000rpm+
Adjust air screw either way to get the fastest idle.
Adjust air screw a little at a time leaving 10 secs or until the motor responds.
Re adjust idle screw for desired idle .
if the air screw ends up being more than 2 1/2 turns out the pilot is too big.
if the air screw is less than 1/2 a turn out the pilot is too small

 

[Tooloose]

Hey Blaaster! Your very informed on these old Yfs 200 engines! Do you still ride these little ol beast? Anyway, just wanted to drop you a line or two and tell you Howdy, and commend you one your extensive knowledgePeace

 

[Blaaster]

I sit on and make Braaaap noises .

I have been known to Granny ride when my Daughter will let me.

It was frustrating last week when I was trying to teach her to get the front up, as there was no way that she woul let me even sit on the bike ...

She is very protective and knows my limitations better than I do...

 

[Tooloose]

Your a good Paw-Paw! My first granddaughter was born on May 15 Hoo-rah and my first Grandson was born last nite Hoo-rah✌

 

[Tonyv913]

I'm having the same problem with mine, I'll try what @Blaaster said!