help ! ..sheared cylinder head bolts

[Ewan 500 K1]

what a pain in the arse ... went to take the rocker cover off for polishing and found that two of the four central bolts have sheared flush.  I'm loathe to use an easy out as I've had them snap off before. Anyone tried the sealey VS7233 stud extractor .... http://www.pvrdirect.co.uk/productinfo.aspx?catref=VS7233  .  .... in particular are the pins liable to snapping in the same way as easy outs ?

[sweetpeauk]

My mate has a set of these and on the first time we tried them the M6 one it snapped with very little pressure, only good thing about them is that they drill out OK with a cobalt drill bit. would it not be cheaper to get a helicoils or the better time-serts fitted.

[UK Pete]

I have always found if there was enough force to break the stud or bolt in the first place then any of these easyout , or stud extractors are not much help,and often break themselves causing more prblems, i have come to learn that it takes a good few heat cycles combined with penertrating oil,  impact plus the need to take time is the answer, when a bolt or stud snaps off i will weld something to the broken bolt top and with the above methods it will usually come out, if it don't then drill it out and fit a thread insert of some type
Pete

[Jimbo550]

Not sure which bolts you mean? Are they m6? Is the engine still in frame?  If you can get to it then drill them out with a slightly smaller drill say 4.8 or 4.9. You should then be able to break up the remainder of the thread with a small point and pick it out of the thread.  If you damage the thread then use a helicoil.

[Ewan 500 K1]

The engine is out the frame and they are M6 by 35mm bolts ... part 28 on page 2 of the cB500k1 parts list , although someone replaced the pan head screws with hex bolts . They are under the breather cover.   Chers for advice guys, I'll resits the temaptation to buy another tool and find mesel a natty welsder if I can

[Jimbo550]

Might be worth checking if they are stainless? That may cause you extra problems.

[Ewan 500 K1]

fine on the stainless front jimbo, they're just the usual steel jobs

[K2-K6]

As the others have said, it's difficult to get the out with an extractor after drilling them.

Assuming that you get the hole as big as possible, then the tapered stud extractors try to push the remaining bolt material outwards to give even more grip which is not what you want.

If the bolt has snapped because the threads are siezed into the head then it will most likely snap any extractor that you put into it as it's an even smaller dia with the tools usually brittle. When it's like this, then Pete's advice is probably the best route to success.