The tourer has a standard (lo compression) head, I haven't removed it yet because it starts and runs well, albeit with a lowish top speed.

The plugs are a mid brown colour, not oily, though I have only done short journeys so far, a dozen miles round trip.

Compressions are 110, 110, 115,115 which seem ok-ish to me.

If I lift the bonnet with the engine running there is a lot of smoke coming out of the tappet cover breather holes. The exhaust is smoky on start-up.

So: am I wrong about the state of the engine, and it is re-bore time?

Or could, say, very worn valve guides be generating the smoke?

I am inclined to fit a single breather pipe with the outlet pointing to the carb intake, and keep running.

Advice welcome.

Thanks, everybody.

Simon

Location: On a hill in Wiltshire

Mail sent

Location: Gard, France 30960. Used to be Languedoc-Roussillon but now it's Occitanie

Hi Simon, First off get the engine up to operating Temp then take the compressions I would be surprised if they are not a lot lower.
The next step is to take the Head off and check the Bores use a telescopic gauge and Mic , not many people will have a Boregauge.
this will give you all the info on a rebore or Honing & new Rings.

Hope this Helps
Colin