Hi I have a tr1 engined wasp sidecar motocross bike.I have had a engine failure the front conrod shells broke,I had another engine from ebay with a good bottom end so fitted my original top end to the ebayed bottom end.My orginal top end had the circular head gasket plus cam chain tunnel seal and also a laminated steel complete head gasket where as the ebayed one only had the ring and seal.Its maybe my orginal cylinder/head has been skimmed,if I build without the complete head gasket you can see a gap between the cylinder/head around the outer edges.Any thoughts?