Broken Bolt SOS!

[devauxr]

First off I have a 1980 gs850gl.

Saturday I was working on my bike and as I was reinstalling the cam bearings I very unfortunately snapped one of the cam bearing bolts off in the head. It was really weird though, it definitely wasn't cross threaded and I had a torque wrench on it so it maybe had 6-10 pounds of torque on it (specs call for 7 but I was reading it just as it snapped so I'm not sure exactly but it definitely wasn't over 10). Now for the really bad news; The bolt broke off lower than flush, the top was jagged (highest point being the center) and also I had blue loctited the bolt which leads me to my next catastrophe.

So today I was trying to remove the bolt using a kobalt bolt extractor but I missed dead dead center on the bolt when drilling and that little bit off combined with the loctite means I don't think that things is coming off (unless you guys have some awesome suggestions.); although I was thinking that the combination of steel bolt and aluminum head might make heating the head a very viable option except for the fact that it's so close to the cam journal.

So my questions in lieu of any seriously miraculous tips is what is my next course of action? Is going to a machine shop and seeing if they could take it out a viable option and if no is drilling it out and putting in a slightly larger bolt an option? or should I just scour ebay for a cylinder head and hope the mighty motorcycle gods feel I am worthy of there pity. If it helps I can add pictures tomorrow but it's too dark to get in there tonight to see it.

[SqDancerLynn1]

Depends on your torque wrench, if it was on the bottom of the scale it is NOT accurate you could have torqued it way off. Take the cam bearing cap off and their may be enough to twist it out. OR Take a small chisel & try and turn it.. .Or try drilling with a left twist drill. Worst case you have to remove the head and have it heli coiled. Don't go to a larger bolt..

[devauxr]

Ah didn't even think of that. Yes that does sound like a good option but i'd still rather try and get the bolt in it out and save it any thoughts on torching that aluminum head? too risky?

[Nessism]

Heating the head is not going to help much. It's very hard to get the head hot enough to help since there is too much metal around that bolt hole.

Your best bet is to drill the hole even if it's off center, but use a small drill bit, and then work the bit sideways to enlarge the hole until it's centered. I did just this recently when extracting a broken bolt just like you describe. Using left handed drill bits may help. Once you get the hole centered, step it up one size at a time until most of the bolt is out. Typically the last bits of the bolt will come out just as the hole reaches the edges of the aluminum assuming you are using left handed bits.

If you broke off the extractor, or hit the aluminum already, you are in trouble. Going to a solid threaded insert is always an option though so no need to get a new head.

[rapidray]

Loctite? You don't Loctite cam cap bolts! Do what Ed said but use LEFT hand drill bits if you can. When you put it back together, do NOT use Loctite!!! Ray.

[devauxr]

Loctite? You don't Loctite cam cap bolts! Do what Ed said but use LEFT hand drill bits if you can. When you put it back together, do NOT use Loctite!!! Ray.

Well i'm not going to anymore, lol. I didn't know that that was a no no. my bad. I haven't broken off the extractor on the contrary I didn't want to get to that point, knowing that I wasn't centered I stopped immediately. I'll try working it sideways but i'm worried about knicking the threads; but I guess that's not much of a worry if i can't get the bolt out, and there's always inserts. On that note anyone know a good machine shop in Durham Nc area?

[rapidray]

Isn't that NASCAR country? Should be good machinists every 100 yards or so! Ray.

[SqDancerLynn1]

I missed the part where you said you used loctite ! Your screwed !!!

[Pete Logan]

Your screwed !!!

That's what we call a Technical Term

[devauxr]

I went with blue loctite which i've never had a very hard time getting out... although i've usually had a bolt had attached, lol. So it definitely sounds like i'm on the prowl for a machine shop.

[crapwacker]

i'd grab a head if you can locate one. put it on. you'll get at least $20 for scrap in the other f'd up one. IMO

[Don-lo]

When you drill into it, you will heat up the bolt enough to release the blue loctite. The left handed drill bit should work well. A small jig above the bolt hole can help you drill straight, so you can use progressively bigger bits (or even a small endmill to flatten out the top of the broken bolt).

FWIW, a common cause of broken bolts on the cam caps is oil in the bolt holes. The oil stops the bolt before it is snug on the cap, so people keep snugging. It also produces a mushy stop, as opposed to a nice firm dead stop.

[tkent02]

Isn't that NASCAR country? Should be good machinists every 100 yards or so! Ray.

Yeah, but these are metric bolts, Ray!

[devauxr]

Yeah, but these are metric bolts, Ray!

It's funny you say that. A guy I work with is an ex pit crew guy and I asked him about machine shops and he said if it wasn't metric then he had the helicoil kit already.

Also the oil thing makes sense I definitely had some in the hole as I had just oiled the channels as per the manual and i'm sure i slopped some in that hole.

[four_shot]

If you did gett oil in the hole, you may have gotten lucky 'cause the loctite won't adhere to an oily surface.

I'd try the lefthanded drills.
Stick with a slower drill speed, it should help with the bit biting into the bolt, and hopefully spinning it out.