Oil leak from head.

[McCabe-Thiele (Ted)]

To replace the head gasket risks disturbing the bottom block seal gasket & four base rings. Not sure if members here would take a risk and just replace the head gasket only.

Care has to be taken when removing the camshaft as you don't want a bolt or the chain to drop down into the engine.

[Bradders]

That sounds quite a way beyond my mechanical skills. Thanks for the info Ted.

[McCabe-Thiele (Ted)]

The thing about mechanical skills is they improve if you challenge yourself to try to fix something, when it works you gain confidence to progress to the next level, we were all novices in the past.

Although I was/am semi-skilled as a teenager back in the 1960's working mainly on BL A series engines so I did have some basic mechanical knowledge. I knew the difference between a normal left hand thread and a right hand thread. When I worked on the only Alfa Romeo I have ever  owned it took me a while to remove the left side road wheels - yep like some old Jaguars the wheel nuts are a left hand thread on one side, right hand thread on the other side. By the time I was 40 I had stopped servicing my own car as I could afford to take it to a garage. For the next 30 years my A/F spanners remained in a tool box going rusty.

In 2020 at the age of 72 I bought my first full Metric Tool Kit so I could try to restore a 400/4 , I had never fully dismantled a motor cycle crank case in my life. I learnt the hard way (hence my Ground Hog days), spurned on by the help on this site I found confidence in leanring new skills and re-discovering long lost ones.

I'm not saying this to blow my own trumpet or big myself up. I was where you are in 2020 we can all learn new skills if we take a risk - even more so if we don't have to have the bike running by the next day to get to work.

I draw the line with learning to play any kind of musical instrument - my CD player does that for me. As for learning to dance well I did manage the Waltz until the teacher stopped calling out 1-2-3, 1-2-3, 1-2-3 - it's a bloke thing I suspect.

[flatfour]

I changed the head gasket on the 400/4 that I am looking after in around four hours of spanner time, although this was divided into two sessions as the new gasket, when fitted, was left to settle overnight and then re- torqued in the morning before fitting the camshaft etc. The cylinder base gasket and everything below head level was left untouched and has not shown any issues since. When I lifted the head, I did, however ask the bike's owner to firmly hold the cylinder barrels down, to avoid moving the base gasket.

I often work on the "old" bikes and did the same work on my Benelli Sei a good few years ago, however my only real skills were learned in the 1970's and 80's when I was a "chalk and talk" technical trainer for Jaguar Cars.

In all honesty, providing that you can follow the manual and possess a few workshop tools including a good low - range torque wrench, I don't see the job as something that the average DIY mechanic would have trouble handling.

[Athame57]

The thing about mechanical skills is they improve if you challenge yourself to try to fix something, when it works you gain confidence to progress to the next level, we were all novices in the past.

....and when something goes BANG confidence wanes!  Actually a lack of facilities meant I have to farm out the big jobs to the professional's, but I've got to know my bike really well this past six years doing what I can do.

[McCabe-Thiele (Ted)]

The thing about mechanical skills is they improve if you challenge yourself to try to fix something, when it works you gain confidence to progress to the next level, we were all novices in the past.

....and when something goes BANG confidence wanes!  Actually a lack of facilities meant I have to farm out the big jobs to the professional's, but I've got to know my bike really well this past six years doing what I can do.

True we learn more from our mistakes than our easy success's, during my 400 rebuild I did have my Groundhog Days - I call it the learning dip as opposed to the learning curve.