I have a similar question to daniz24:

I ran my 2nd JP FX Palmaris today and I have a head clearence of 0.4mm (measured with a piece of solder wire). I run 16% fuel and a 6TF plug. Air temp was around 16C.

I found that the power was excellent, but I couldn't get the temp above 100C without it leaning out completely.

The car would bog down (lean not rich) coming out of a hairpin after a few laps. At first, I thought it was the LSN too lean, but even after richening the LSN right out, the problem persisted.
I leaned the LSN back again (it idled at 70-75C) and richened the HSN, the power was back, but the temp after a hard run was 85C.

Is this because the head clearence is too small?

If I put another 0.1mm shim in, would this stop the engine leaning out at low temperatures?

Cheers, Mark.