Hard to pull srart

[ddrew]

Exhaust .20 intake .15

It's a Honda 390 clone

 

[ddrew]

Hope you mean .020 and .015?

Yes

 

[Fish]

Exhaust .20 intake .15

Are you sure? .015 and .020 still seems too high for a flathead, let alone an OHV.
I am thinking like maybe .004 and .006 or so.

 

[Scrubcadet10]

.015 and .020 is what honda specs for the GX390.