What are you using to measure temperature? 230 is too cool to vaporlock, but that sounds like what it's doing. Unless you're using an Exergen, there's a reasonable chance it's actually hotter... might give it a spit (or water) test to confirm. Hot enough to vaporlock (300+, perhaps), you should see violent boiling. If it's that hot, you could have an airleak... around carb base, at the banjo fitting, around backplate, through front bearing. Seal these areas with high-temp silicone or Air-Seal.