Oil pushish out from engine

[rowdypat]

I once found a spade-like blade gadget that connects to the tacho cable hiding in that cavity around a spark plug hole, I was using compressed air to clear out any crap before pulling a plug and I thought I saw something move. It was wedged in snug forward of the plug but came out with a magnet. Who knows how long it was floating around in there. Very happy it didn't go down a plug hole at some point over the years.

Good practise that Vince

 

[TheWrongTrousers]

It doesn't go into the crankcase Ron, it just drains (normally water) from the well beneath the starter motor. there is a similar hole in the 750's but it drains into the starter chain area which is in air. The triples sprag clutch runs in oil so they moved the hole to drain into the front sprocket area.
If it's blocked you end up with a nice swimming pool around the starter when washing the bike. Ditto the spark plug wells on the triple.

This is really helpful. I am in the middle of rebuilding my engine and i noticed this hole for the first time ever. i have been wondering what on earth it is for and then after having a good look and a bit of a think, I sort of figured it out myself, but its good to have it confirmed. Thanks guys.

 

[Haggis]

Some years ago I found most of my spark-plug-well drain holes were blocked by poor casting. I opened them with a long drill, 3mm from memory. Biggest benefit was finding I had the cam tunnel corner crack forming as oil now appeared at the front of the engine - it could find its way forward after being previously stuck in the centre plug well. Should have left the holes sealed

 

[Chuck3CL]

Some years ago I found most of my spark-plug-well drain holes were blocked by poor casting. I opened them with a long drill, 3mm from memory. Biggest benefit was finding I had the cam tunnel corner crack forming as oil now appeared at the front of the engine - it could find its way forward after being previously stuck in the centre plug well. Should have left the holes sealed

Hmmm, similar problem on my other triple, a 2018 Triumph 800 XCX.....I spotted minor oil deposit near the plug weep hole. Not water, but oil weeping? After replacing rocker cover bits still had oil. Fortunately one month left on warranty. Turns out the head was a porous casting and needed to be replaced. Oil was coming through the casting into the spark plug cavity. Lockdown hit, took months to get parts and service. Can't complain, after 2 years of use on the bike, I got a complete new head (engine head that is, not mine), valve assembly etc on warranty. I imagine those 1970's heads had their share of porous castings too.