i just put on a hmf system and now at idle it will raise the rpms for a couple of secs and them drop back down and then keeps repeating, i cant figure it out. has any one ever experienced this. if so how did you stop it?

 

Any carb work done? HMF calls for 145 f - 148 r jets for full system and 142 f - 145 r jets for slip on.

 

And you may need pilot screw adjustment -- for idle mixture quality