Hi Seb.
Just to clear up some confusion, I'm flying a Jab 160 (the avatar is my old Streak Shadow, with a rotax 582).
I have 300 hours on the engine (and airframe), and the last leakdown was 80/78 on all cylinders, so no probs there. I have put the Jabiru recommended jetting in about 100 hours ago (except the idle jet which from memory is a "35" instead of a "45").
Ambient temps are about 20 C (I use a simple digital OAT thermometer).
The new CHT probes are from Sonex, and designed for a Jab 2200 (old thick fin heads only) Sonex Web Store - AeroConversions CHT Probes (set of 2) AeroConversions CHT Probes (set of 2)
About 10 engine hours ago, I added a flat aluminium plate BEHIND the oil cooler- it is attached to the shield in front of the muffler, and extends about 12 inches parallel to the oil cooler. The thinking here is to direct the oil cooler air "exhaust" down towards the firewall, and prevent/minimise it mixing with the low pressure air from the heads. I have seen an observable decrease in all CHTs of about 25 F. The original gauge (head #4) NEVER goes over 300 F now, and that figure is backed up by the new gauge. A quick and dirty installation, but after this success, I am going to try to enclose and capture that exhaust air more completely.
However, that #4 CHT is annoying.
Cheers
Gerry