February 21, 2018

How to correct a machining error in oem Harley Davidson head bolt thread drill too deep

Hi to all

Sometimes manufacturers make maching mistakes and it take a while sometimes to found the issue,and many often left facory like that and sometimes even worst,quality control was almost non existent in the past,often today .

Here it is ,you can barely see a black spot in the bottom of the thread(holes going throught drain hole cavity),the hole was drill too deep from factory and oil coming to drain to the bottom of the cylinders was sligthly leaking the head bolt thread all the way to head gasket,and into combustion chamber,so this is what I did to correct the problem.




screw from a bolts cut,blast,screew driver slot,Loctite primer then ,high temperature Red Loctite with a Q-tip at the bottom of threaded hole,screw in place,I did not need to cut the head bolts the remaining thread was a little bit more than the protruding length of head bolt



clean the thread with the correct tap,then counterbore ,and surfacing heads,





the only thing left on this head to do is to touch the seat with a 3 angles valve job,



Hope you have enjoy this thread,saddlebagrail

Filed under Engine & Transmission, Motorcycles, Other, Random Ideas, Resources, Restoration, Saddlebagrail's blog, Tech by saddlebagrail

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