Drilling holes in my engine

[uudfourty]

Dear old GS people who've done this longer than I have,

My PO, in his infinite wisdom, didn't use a torque wrench when putting the valve cover back on and I have oil leaks now. You can imagine why.

Completely stripped ( I was able to unscrew the aluminum threads off of the bolt) one of the head cover bolts. No ghost of a chance of threads left. The bolt is on the far back far right side, on the corner.
I'm not going to get into anything if I either
A) drill and tap a larger hole or
B) drill a same sized hole the rest of the way through (like the one opposite it on the front side) and tap the hole the same size.
I don't know how much meat I'd really get ahold of if I went with option B, and would rather do A.
There isn't some secret mystery passage I'll hose up if I tap this a size bigger is there?

I can't imagine that there would be, but I thought I'd better ask before.

Thanks in advance.

Sincerely,
Awesome in Amarillo

[doctorgonzo]

I'm doing not one but TWO broken off bolts in my cover this weekend. I'm going to use a heli-coil. Those bolts (on a GS1000) are 6mm X 1.0. Heli-Coil says use a 1/4 bit. I am going to use a stop on the drill to drill to the same depth as the other holes (they are all the same).

[Zooks]

Arrrggg!!!! HELL E COIL!!!!! Arrrrrggggg!!!

j/k (not a big fan)

Seriously though, don't use a heli-coil when you can use something more permanent like this - http://www.timesert.com/ . This is what most engineers are using these days. They are superior to heli-coil 100 fold (or more). http://www.locknstitch.com/inserts.htm - This is a similar type of system.

There are various types on the market. Some expand in the hole whilst others are glued in place with high strength epoxy. Either way, they seal properly and will not come out, unlike heli-coil.
I was just talking with an engineer yesterday (that builds V8 motors for race cars) and he said he used these types of things all the time. When I mentioned heli-coil he laughed and said he hadn't used a heli-coil in over 10 years.

[doctorgonzo]

Header bolts still to go (at a later date). I'll look into the time sert.

[uudfourty]

I wasn't planning on using any kind of insert, but a drill and tap. Are you trying to tell me that there's something on the outside, right next to the half-moon on the back side that I might get into?

[Zooks]

No, sorry that was slight thread hijack. *oops*

I am actually not entirely sure (as to your original question).

[doctorgonzo]

I wasn't planning on using any kind of insert, but a drill and tap. Are you trying to tell me that there's something on the outside, right next to the half-moon on the back side that I might get into?

Yeah, sorry fpr the hijack...

Don't think there is anything you'll hit. At least hope not because I will hit it when I drill mine as well.

[PAULYBOY]

I'm doing not one but TWO broken off bolts in my cover this weekend. I'm going to use a heli-coil. Those bolts (on a GS1000) are 6mm X 1.0. Heli-Coil says use a 1/4 bit. I am going to use a stop on the drill to drill to the same depth as the other holes (they are all the same).

Been awhile (24 years) since I've used a helicoil, but if you're planning on drilling a hole to depth instead of all the way through, you're either gonna need to compensate for the amount of space the drill bit won't get to (the pointy end) or use a flat bottoming drill bit, such as a metal reamer type for a milling machine. Amazing what 1/8" will do to a normal male when something's off by that much.

[doctorgonzo]

Been awhile (24 years) since I've used a helicoil, but if you're planning on drilling a hole to depth instead of all the way through, you're either gonna need to compensate for the amount of space the drill bit won't get to (the pointy end) or use a flat bottoming drill bit, such as a metal reamer type for a milling machine. Amazing what 1/8" will do to a normal male when something's off by that much.

Whoa, good tip, thanks!

[phaserburn]

What kind of bike do you have? I have a few top ends laying around for the GS850 and 1000 motors and can send you a good top portion (where the cams are).

Let me know

[doctorgonzo]

PM sent on 1000 Top end.