Headbolt threads in alloy barrels

[bushybester]

I looked & still can’t quite follow, anyway if the lower section into which the head bolt screws are an insert of some sorts and are loose, take them to a welding shop and have them welded and re-tapped.

BB

[Rob D]

Originally Posted by timwil

Hi Everybody, I am glad I am getting some interest in my problem. My head bolt threads are in perfect condition.

The problem is that 2 of the steel inserts that the threads are tapped into are riseing. These are not helicoils or any other kind of repair. I have recently found out that these incerts are original on mid 50's 500cc alloy barrels.

Ahh, I did not know that about the alloy barrels Tim, sorry to make the confusion here.

Yeah, still possibly a locking pin to hold the stock insert from rising...?
I would bet that they are pressed in but I don't want to speculate anymore...

Best,
Rob

[timwil]

BB, are you suggesting that I drill out say the top 1/8" of the inserts including a bit of the sleeve flange where it overlaps the insert and then run a fillet weld around the top of the insert welding it to the alloy barrel. Can you weld steel to alloy? Would this weld handle the 18 ft/lb of tourqe? It occurs to me that these inserts can't rise much more if any as they will butt up against the sleeve flange where it overlaps them a bit. Do you think that if I ran it like that that it would distort the sleeve? Tim