TOPIC:

I just smear my gaskets with fresh oil. It helps them to stay in place while the other mating surfice is fitted.

I never use a sealant as it's the gaskets job to make the seal and an additional sealant makes them really difficult to remove.

I have no technical reason to back this up - it''s just what I do

I was investigating Zed_13s suggestion regarding the crankcase breather  and I may have found the possible cause for debris getting into crankcase. The airbox is in two parts with a rubber gasket glued to a thin metal frame sandwiched between them. The gasket sits in a recess in the lower part of the airbox. The rubber part on mine had come adrift from the metal frame, leaving quite a bit of space for rubbish to get drawn in. The bottom of the airbox was a bit gritty as well. I’ve marked on the photo where the gasket sits. 

McZee wrote:

I was investigating Zed_13s suggestion regarding the crankcase breather  and I may have found the possible cause for debris getting into crankcase. The airbox is in two parts with a rubber gasket glued to a thin metal frame sandwiched between them. The gasket sits in a recess in the lower part of the airbox. The rubber part on mine had come adrift from the metal frame, leaving quite a bit of space for rubbish to get drawn in. The bottom of the airbox was a bit gritty as well. I’ve marked on the photo where the gasket sits. 

 

My 79 had that exact same problem - more than once.

Finally got the big old Z up and running again. Replacing the valve stem oil seals has cured the excessive oil burning, so no billowing smoke on start up. I had a problem getting the thermostat housing to seal, took me four attempts, a new gasket and several applications of sealant before I got it watertight. I Discovered that if you bung up the bottom hose with the cap from a T-cut bottle and fix a bit of plastic pipe to the top hose, you can fill the system with water and test for leaks without fitting the radiator. The repair I did to the exhaust is holding up well with no sign of leaking, so I’m going to call that a success - see photo- my repair lasted better than the exhaust paint I applied. Cleaned the carbs and set the needles to three and a half turns out, which if probably a bit rich but I will do a final adjustment on them later when give the cylinder head nuts a final check for torque. I also reverted back to a cable clutch, the hydraulic conversion worked well to start with but as time went on I felt it wasn’t fully disengaging, giving me clunky gear changes and difficulty finding neutral when stationary. Overall I’m pleased with how it’s turned out.