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Cylinder head thread repair?


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1 hour ago, Gmc28 said:

That would certainly  be best.  I just offered the low lying fruit.... and like to know if there’s something else amiss if the Italians think one size should fit but then it doesn’t match what i find, so then i pause.  I found a sheered bolt at one point, but it was a (fairly) clean sheer, so took me an extra minute of head scratching when reassembling from the batch of bolts in the parts tray as to what was going on. 

I've been working on building, racing, riding Italian bikes for over 35 years and I have no idea of what Italian engineering logic is. Dont think I've experienced much of it to be honest.

Of course add to that Muppet's working on particular bikes as they age and change hands and anythings possible. In the OP's case the aftermarket head protectors require different length bolts but who knows whether they're the "right" length bolts. 

Ciao

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Recently, I replaced an imploded valve cover gasket. Some prior F-1 mechanic had put washers under the guard at two of the four screw holes. And used two different thickness/O.D. washers at that. Thus, two of the four screws were then working to pull the guard down flush. When tightening such an "arrangement" the threads will feel soft, but are really pulling the guard down the 0.5-1.0 mm gap caused by the washers. My rule of thumb: Trust nothing and nobody who has touched your bike before.  Not the engineers, assembly workers, prior owners or "mechanics."

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1 hour ago, po18guy said:

Recently, I replaced an imploded valve cover gasket. Some prior F-1 mechanic had put washers under the guard at two of the four screw holes. And used two different thickness/O.D. washers at that. Thus, two of the four screws were then working to pull the guard down flush. When tightening such an "arrangement" the threads will feel soft, but are really pulling the guard down the 0.5-1.0 mm gap caused by the washers. My rule of thumb: Trust nothing and nobody who has touched your bike before.  Not the engineers, assembly workers, prior owners or "mechanics."

You sometimes need to do that so the guard bears down on the cover at the mount hole locations but you need to use special 11mm OD 6mm ID washers as anything of larger OD will cause a clearance problem to the valve cover. The Daytona/Centauro needs these smaller OD washers as well on the valve cover. I buy Titanium ones off ebay but have also made them up from Ti bar raw stock as well. Nothing looks worse than a 6mm washer thats 13mm in OD when it doesn't need to be.

Ciao

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