Broken Cylinder Head Bolt

[jacksondee]

Well, as I've seen from other posts here I guess this seems to happen from time to time.

Tightened down the cylinder head cover bolt a little too tight in its helicoil and snapped it off.

Started to drill it out with success. The pilot hole went nice and smooth. I put the extraction thingy in the hole and started to twist, and the tip of the extraction thingy broke off in the hole I had just drilled. Now I've broken off 3 drill bits and used 2 other including some 'cold fastened' steel one or whatever the heck. I've got a bit of an ugly pilot hole drilled again but no matter which bit I use or how hard I lean on the drill, I just cannot get this hole drilled any deeper.

It looks ugly because I am at about hour 2 of just this, and as I've said, I'm on my 5th drill bit.

The bike is otherwise 100% ready to ride, except for this busted bolt with was the very last thing I was tightening down before being ready to ride for the rest of the summer...

Do I get a bit with a pilot tip on it? Do I try with a very small bit first? (I've already tried this)

Am I missing something? Does someone sell some kind of diamond tipped bit that eats through anything like a hot knife through butter, etc?

Please help!

 

[xb33bsa]

stop, put down the power tools
take it apart
it is the cam journal upper saddle dealy if you ruin it a replacement is not really viable because they are matched to the head

take it to a machine shop they can put it in a vertical milling machine and use a carbide endmill
then have them make up a custom thread reducing insert adapter if needed

 

[jacksondee]

Thank you. I didn't realize that could be disassembled. I will investigate further.

I've not taken the camshaft out yet and indeed the manual makes it look like that part of the camshaft holder which can be removed includes the cylinder head cover bolt hole. I didn't even realize this. I could have removed it all and had it at the machine shop last week instead of waiting until this weekend trying to dig it out like a fool.

Thanks XB.

 

[xb33bsa]

yep live and learn you proly got some metal chips in there but some careful work with the vaccum cleaner should take care o that
when removing just that one cap not a bad idea to rotate the engine so both the nearest cam lobes are loose