Front Drive Sprocket Bolt Head sheared off

[Georgelogue]

I torqued the head off the bolt of the front drive sprocket on my 79 CB750. I was using a dremel to flatten the bolt so i could drill into it to extract it. The bolt ended up going all the way through the countershaft and is sitting in the countershaft now. I managed to get a magnetic retriever to get the bolt started back out, but the magnet isnt strong enough to turn the bolt enough to put pressure back on it to extract. I know this is a pretty specific problem that hasnt happened to many people but wanted to see if anyone had any ideas as to how to get it out without splitting the 2 cases apart. I just put the engine back into the frame last week and it wasnt fun. If i didnt just get my frame powdercoated i would just pull the engine again but im trying to avoid that at all costs. as you can see in the one pic, i got the bolt started back in the threads, but it keeps pushing back into the shaft because i can't get enough threads going.

 

[Tim]

So... it's hard to tell from the 2 photos but is there a section of the bolt protruding? Can't grab it with a pair of needle-nose vice grips or something like that?

A steel rod with some JB Weld on the tip might stick to the end of the bolt shaft or other 'glue'.

 

[irk miller]

Do you have a really sharp punch? You can tap it out with a punch.

 

[pidjones]

Left-hand bits?

 

[doc_rot]

Ditto on the left hand drill bit. Hands down the best way to extract broken studs in a home shop.

 

[irk miller]

Just curious. Are those RH or LH threads? If there's one scenario where Honda would use LH threads, it would be for this because of direction of rotation. My 78 was RH, but just making sure.

 

[teazer]

As they already said. Left hand drill bit FTW.

 

[Georgelogue]

So... it's hard to tell from the 2 photos but is there a section of the bolt protruding? Can't grab it with a pair of needle-nose vice grips or something like that?

A steel rod with some JB Weld on the tip might stick to the end of the bolt shaft or other 'glue'.

I almost tried the jb weld on the tip... Ran out of time today.... I think that's the best bet. Too much pressure and it pushes back into the counter shaft. I can only get it threaded about a quarter turn, if that.

 

[Tim]

Near as I can tell this is the diagram of the parts. You sheared #15, it's still threaded into the countershaft (#2), but if you press on it, it actually moves further into the countershaft?

Not sure I understand this part. If it's threaded, it shouldn't of course be able to move in and out without rotating it.