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was a little set back when I found this but have had a good look and will run it again hope doesnt create hot spots , When I pulled the motor down I found excess use of silicone and maybe it wasn't a neutral cure silicone and the acid has attacked the head , Dont Know. maybe just poor manufacture. If it gives me trouble in the future will just have to replace it. Been a heavy diesel mechanic for 45 years and come across gaskets that have been plastered in some form of gunk too often, If you have good straight surfaces you dont need anything but a quality gasket unless the manufacturer calls for it. MTBW baixar imagem do instagram
Yes it wouldnt be too much of an ordeal to weld and machine, you've talked me into it Damn. Ive had the bike for 15 years and 70000ks and never had a head off in that time, I imported the bike from power motors IL .who would know its history.
Would detonation do damage like that around the gasket? I know it can pit piston ring grooves.
I would concur on the silicone sealant theory, silicone sealers give off acetic acid and may well have been the inital cause of corrosion. Moisture and lack of oxygen when sitting in storage and you have the perfect soup for the aluminum to degrade.My $.02 As per Pink Floyd........ "there's something in my head, but it's not me." Paul B
Could be detonation as its all inside the fire ring of the gasket and some around the guide and peeking out from under the valve seat, I just have to deal with it. Only on the right cylinder and nothing on the top of the piston which makes me think it happened before its last rebuild as it has cast bores so not original for a 73, maybe the piston looked like the head so replaced it and only that right head gasket with the excess of silicone as if they were trying to help a pre existing problem. I know for a fact it had chrome bores originally because when I cleaned the sludge trap it was full of chrome. {Just Lovely, where do these people come from. Really) and only one nice neat centre punch mark on the bung like factory. Hmm maybe they just replaced cylinders only and never removed crank. If only our bikes could talk to us. Ray
I did my apprenticeship on Detroit 2 stroke diesels and due to very quick expansion and contraction of a 2 stroke cracked cylinder heads between the valves were a weekly thing .
Pics would be good, between valves on a 2 stroke.?Eldo heads detonating around squish easier for my head.
That looks as if it could be a bit of detonation (pre-ignition)? Did you notice any pinking from that cylinder?
I ruled out the detonation theory when I saw the same issues in the exhaust port. My bet is still on a bike left sitting with water in the cylinder. You'll also notice the damage is noticeably worse on the lower side of the head when fitted to the engine, ie the spark plug side. So piston at or near TDC and water sitting in the cylinder.
You realize that detonation and pre-ignition are NOT the same.