Exhaust Bolt Broke Off

[landshark]

Are you trying to use a drill with the easy out?

[Steve314159]

I just went through this ordeal. I tried welding a nut onto the exposed stud four times but the weld or the bolt broke. My advice is to 1) file the bolt flat and center punch a dot in the middle of the circle, 2) using a small bit, drill a hole in the bolt, straight down, I mean you're trying to drill a hole 3/4 inch deep perfectly straight through the old bolt, use every method you can think of to get the angle correct. Eyeballing it is what I used and missed by 1/16 inch. Then increase the size of the drill bit a little at a time. 3) Tap new threads for your new bolts.

For my '80 550 I have 8mm bolts. From a chart on the internet I learned that the final drill size should be 17/64 inch if you want to tap new threads. I did that and everything is back together.

The left handed drill bits did not provide any advantage.

I am ready to ride tomorrow since the temperature is supposed to be 45F. My license plate still says 1992.

Steve (not the crabby Steve)

[chef1366]

I used an easy (aka never) out with heat and I got one out pronto. Engine was in the trunk of my car though.

[Octain]

Every time I read one of these "broken exhaust bolt" threads it makes me cringe, there are ways to extract these bolts without breaking them but people just don't research before they get all heavy handed.

Oh I researched, trust me.

16 bolts(intake and exhaust) on a bike thats not had a wrench on it in 30 plus years and only two broken. Not to bad if ya ask me.

[djg42]

well, it still wont budge and im not pushing it-i dont want the extractor to break. How difficult would it be to replace the part? I wonder if id be more cost effective. What parts would i need? Thanks,

[Smokinapankake]

Common household ammonia will attack the alum. surrounding the bolt, thereby breaking that bond. Don't use too much though.

http://sheldonbrown.com/stuck-seatposts.html

This article covers removing a stuck aluminum seatpost out of a steel bicycle frame, but the principle in step 13 (or XIII for those who can't do the conversion) applies here also. Steel bolt on aluminum head. The trick is getting that ammonia down into the threads, where the bond occurs.

I've used this on my 84 Kat with reasonable success...

[Octain]

well, it still wont budge and im not pushing it-i dont want the extractor to break. How difficult would it be to replace the part? I wonder if id be more cost effective. What parts would i need? Thanks,

A head............

[djg42]

if i replace the cylinder head will I have to take the whole engine out or can I leave it in?
THANKS

[Billy Ricks]

if i replace the cylinder head will I have to take the whole engine out or can I leave it in?
THANKS

You don't need a new head. If you can get a drill in the right spot just drill and tap as already recommended. A tap might cost you $10 at the most. You can check the length of the other bolts and put some tape on the drill bit so you drill to the right depth. I broke one off on my bike and drilled and tapped with no problems. Since then anti-seize compound on the threads every time the exhaust comes off.

[djg42]

Thanks everybody, i decided try and drill it out and retap it before i spend a couple hundred having someone else do it. The bolt is 8mm, 5/16 inch. On the re-tapping tools some say a thread per inch. Do i have to find a certain thread per inch, or does it not matter?