minor detail question - carburator manifolds

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joe czech

joe czech

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this maybe a dumb question, but what is the correct (factory) finish on the two carburetor manifolds? I would think, natural aluminum, or aluminum alloy. for some reason, mine are painted silver. I can't trust or second guess anything on my 74 Mk2 - damn near have to question everything - :D
 
joe czech said:
this maybe a dumb question, but what is the correct (factory) finish on the two carburetor manifolds? I would think, natural aluminum, or aluminum alloy. for some reason, mine are painted silver. I can't trust or second guess anything on my 74 Mk2 - damn near have to question everything - :D
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That was standard on my then new 850Mk2a 1974 .
 
I think my manifolds were painted silver on my mk2a
 
Dec73 Mk2a, no silver paint including the engine cases which I believe I was the first to spilt.
 
My manifolds were unpainted alloy, but who knows what happened before I got them. My engine cases were painted, as I believe it
was the factory practice to seal up the very porous sand cast cases so as to not leak oil.
 
mine appear to be sprayed - not brushed. IF a previous owner painted my original manifolds, they did an outstanding job - they were very neat and very anal about their workmanship. definitely a factory like finish quality. I do find it odd that the factory would paint these pieces whereas the carbs and cylinder head are a natural finish. right now, and after reading some of the above, especially from Mk2a owners, i'm leaning toward the silver paint from the factory. one thing for sure, they were painted after the carb mounting studs were installed. I cleaned up my originals with simple green and a small nylon brush. they came out very nice and in a ready to install condition. looks like i'll leave things as is, unless someone can prove otherwise. thanks for the feedback - :)

edit note - second guessing here - one thing, these manifolds appear not to be aluminum or a high aluminum content alloy - casting are too heavy. just guessing, but they may be a zinc-aluminum alloy (there are basically 3 different alloy percentages used in manufacturing. what percentage are these, I have no idea, and I could be totally wrong on the alloy thing). the silver paint may be strictly a cosmetic thing due to the nature of the casting material used. side note - the silver color appears to be the same silver used on the U/L fork yokes - o_O
 
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follow up question - the factory lock washers used - are they internal tooth, or split lock washers? I see McMaster-Carr has smaller O.D. splits for cap screws. I did find smaller diameter splits in the parts box, but only three of the four needed. not even sure they're the ones for the manifold cap screws - just trying to put the puzzle together. the parts book and Old Britts exploded view diagrams shows what appears to be tooth lock washers. also, I have replacement stainless cap screws. were the originals black oxide caps? again, three in the box and four needed....
 
The exploded view of manifold washers shows what sure looks to be internal tooth locks -

minor detail question - carburator manifolds


... But the description shows a plain washer -

minor detail question - carburator manifolds


It's been a while since I've had mine apart, but I believe they're star washers. My screws are black.
 
Silver paint on inlet manifolds is probably there to cure porous castings.
 
September 73 build date - unpainted aluminum manifolds and cases. I am the second owner and bought the bike with 1,100 miles on it 40 years ago. It was completely stock and unmolested.
 
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