Head Gasket

Hello,

1970 Commando, smoke out of LHD exhaust, popping and banging out of same exhaust, oil round the front of the heard, could I be fairly certain the head gasket has blown, Just as I thought I'd got the thing sorted.
Any other ideas would be appreciated.


Thanks

Ron

You put silicon under the front two top nuts by the push rod tunnels? Carbs balanced? I had same symptoms and those two fixes took care of oil leak and banging. :wink:

Strange symptoms for blown head gasket. The weak spot to exterior is RH oil hole.
Had one blow out there and almost gas jet open the fuel line before stopped. It made rather dramatic noise but was still making head way so thought to ride on till the fuel line came to mind, YIKES.
Interior leak could cross over and fart with one jugs combustion, but generally its blown into push rod tunnels for oil out breather and seams.
I'd sure check other stuff thoroughly before popping the top.
Do not ever fit the foil over paper type gasket nor Al.
I prefer Hylomar as its Hi Temp and any over moosh stays attached, does not come off and travel and clog.

Head gasket leak would be evident by a hissing noise, and you'd be able to feel hot gasses escaping by holding your hand near the head/cylinder interface. Smoking could be rings or intake valve guide/seal. Popping on one side is usually a lean condition - air leak at carb or partially plugged pilot jet. If you still have points ignition it could also be timing related.

If the oil leak is in the front of the head it's usually around the pushrod tunnels. The 2 studs that attach the head there often break into the tunnels. The cure would require pulling the head, but often you can make major improvement by installing a check valve in the crankcase breather hose (many threads on that here).