Got a Brillelli 46 that has lost 5 or 600 rpm. When I crank it over by hand there is a "clicking" at TDC. After pulling the plug and looking in I see quite a bit of carbon buildup.

I'd like to pull the jug and see about cleaning her out. Having never done that, I'd appreciate a few tips.
Also, will I need to replace the rings if I do take the piston out?

Cheers,

Andrew.

This engine has the jug and the top of the crankcase as a common piece. You will find this to be much more involved than some engines

I don't think taking a jug off is that difficult and I'm no engine guru at all. 4 bolts and carefully slip it off being carefull to not tear the gasket (should really replace the gasket anyway). You may have a stuck ring. You can clean it up and probably unstick the ring if that't the problem. Maybe a bearing is worn out causing the RPM drop. Lots of things can cause loss of power. Just make sure to take note how it comes apart so you can put it back together correctly. Especially if you take the piston off the con rod.

It's simple and easy. Pull the lower cap off and the crank/piston assy can be pulled out. Before replacing the ring look for wear patterns in the cylinder wall. A used ring will mate better to the pattern of a worn cylinder. The little drift pin keeps the ring lined up. If it's all worn out reassemble and run it till it dies. The complete block can be purchased if you want to keep using that brand.
To reassemble you need to put a sealer on the crankcase halves and around the front and rear seals. "Permatex Gasket Maker" works for this job.

Permatex Anaerobic Gasket Maker works better