Not so great news?

[Pedda]

the intakes have been widened from a standard 32 mm to 36 mm btw.

[johnr]

i agree, the damage isnt that bad, so long as the gasket surface is ok and theres no damage to the bore. its also worth checking that the crank is true as these cranks are tough, but theyre only pressed up, and dropping a valve might knock it out of phase, even a half a degree out will affect the running. check it with a dti on the barrel top face, make sure that the pistons all hit tdc at the right time.

[johnr]

i might have a bare et head in the garage, there are no valves in it, but on the plus side, it has been chemically dipped to bare metal. i will dig it out tomorrow and have a look over it to see what it is like. its been a while since i saw it, but i know where it is.

[PaulD]

Thanks guys that makes me feel a bit better about things. With a bit of luck I can repair the exhaust thread on mine, if not I’ve got two options. Good thinking John, I’ll check the crank before I re-assemble everything. Looking at the damage I would bet it’s dropped a valve and not just broken a ring. The reason I asked about the valve size was I didn’t want to have to buy new (larger) valves, mine look good to re-use after a quick lapping in session. More pics to follow when I get stuck in.

[katmarch]

I used these on my exhaust studs https://www.recoilshop.net/metric-m8-1-25-kit.html

Steve

[fossie]

Remember the offer of a Kat while your is in hospital still stands , you'd be doing me a favour ....an idle Kat is a Kat getting lazy and gumm up !

[PaulD]

Remember the offer of a Kat while your is in hospital still stands , you'd be doing me a favour ....an idle Kat is a Kat getting lazy and gumm up !

Thanks boss, if I can’t get the barsteward sorted in the next couple of weeks I’ll take you up on that. If your stuck for room I can squeeze a couple in my garage

[PaulD]

Well the pain continues
I was about to repair the exhaust thread tonight but as I was looking over the head I noticed one of the outer cam journals had picked up at sometime and is looking very sorry for itself! Weirdly neither the corresponding cap or the camshaft are damaged?
So if the offer of your spare cylinder head is still on John, name your price.

[fossie]

Mmmmm it is looking like this engine is a bitsa, as in bit used to replace others , in all honesty no more than we all do. But Italian servicing of motorcycles doesn't normal go beyond polishing.....seeing as yours was once involved in this regime ......time for the ostrich method ....as in hide it and forget it ...

[PaulD]

Well I finally got up to John R’s place on Friday evening and picked up my new cylinder head. All the big four strokes I’ve ever had have been 100% reliable so I’ve never been inside one (I’m a two stroke man at heart) as I was a bit unsure about the camshafts I took them along for his verdict which was “ they’re totally fooked” Luckily he had a nice pair of camshafts spare which came home with me. I spent Sunday evicting spiders from the casting, cleaning off the preserving oil John had thoughtfully covered all the bearing surfaces with, running various taps down all the threads and getting everything ready for the big rebuild. I’ve ordered some heatproof silver paint to finish the job off. I’ll post some pics as I go along.
A huge thanks to John for his invaluable help, I love this forum and it’s helped me no end so far