Oscillating idle when hot

[Unique427]

Originally Posted by SBSerpent

I will try the phenolic spacer route. Right now, it appears that I just have a 1/16" (?) paper (?) gasket at the carburetor base. I will get at least a 1/4" phenolic spacer to start and see if that helps the situation. I will have to swap out the oval "Cobra" air cleaner because once I raise the carburetor, I will have interference issues between the air cleaner and the cowl. A conventional round air cleaner will solve the clearance issues.

On another note, how does the increased thickness of spacers impact performance? Is thicker better, not just from an insulation standpoint, but from a performance standpoint. Also, do I go with a spacer that has a four hole center or one with a large one hole center?

To combat vapor lock issues there's two ways to fight it.
Cooling the fuel AND raising the chosen fuel's boiling point.

A low cost experiment would be to eliminate all ethanol blends and try
burning only unleaded non-oxygenated fuel.

To find unleaded non-oxy fuel near you consult: www.pure-gas.org.

Also, unleaded non-oxy race gas (Sunoco 260GTX) has a much lower
Reid Vapor Pressure rating than pump gas and will be more resistant to boiling.
Unleaded non-oxy race gas mixes with unleaded non-oxy pump gas if you
wish to blend to a specific octane rating as well.

Might be worth a try before breaking out the wrenches and checkbook.