Fitted one a couple of years (14k miles ago) and left it at 6pm. After removing the cylinder head at 30k I had quite a lot of carbon build up on the piston crown and valve seats. Two valves leaked in a bench-test.

At the same time as fitting the mod I fitted twin GPRs, DNA filter and open top, plus an O2 mod. Valve clearances had always been checked on schedule too.

I'm guessing the xs carbon was down to me and the 6pm setting as the ambient air temp is usually 20 plus here and I must have been running too rich for those two years. I set it at 6 because I , (confession), didn't want to burn a piston crown by being too lean. I should have trusted a 4 pm setting instead.

Interestingly I have an F1 daig tool and have only just found I can see the actual air temp and the 'adjusted' air temp as I dial in the mod.

There is a thread here somewhere about ambient temp / dial position.

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I have a lot of growing up to do. I realized that the other day inside my fort.