Stupid damn Exhaust Manifold bolts, -> Broke off in the h

[Anonymous]

I actually had 2 of them broke off inside the head... however I managed to get one out VERY easily. The other though...PHEW...
I went to tap the hole with a punch to set a pilot spot... and when I did that, I saw something inside the whole move. It appears that somebody (before me owning the bike) had already tried to remove the bolt, and broke their tool off inside the hole.
I have tried about a dozen drill bits... I just keep getting to the point where it will just NOT drill in any further. The hole I drilled is only about a 1/4" deep if that... so no extractor in the world is gonna work now... plus it's a hack job... it's not even a nice centered perfectly straight hole at that.

... I am really frustrated and have no idea what to do next, as I don't want to have to take the head off to bring it in to a machine shop. I suppose I could just get somebody else to do the job at my Local Bike Shop... but I'd REALLY not want to do that unless I had to...

TIA for the input!

[earlfor]

Re: Stupid damn Exhaust Manifold bolts, -> Broke off in t

Its a bit of work. but here is what I would do. Go to a steel yard and buy a piece of bar stock about 12" long, 1" wide and 1/2" thick. Make a pattern of your manifold bolt spacing and on a drill press, drill the pattern. (you want o be able to bolt the template onto the head and have the problem hole drilled in the template and in positon.) The template will keep the drill bit aligned perpendicular and in exact position over the broken stud. For the broken stud, you want the template drilled to fit the size of the bit you will be using. All others will be drilled to fit the manifold bolt size. You can start off small and redrill on a drill press to match bits as you increase drill bit size. For drilling very hard materials, you will need to keep the bit oiled as you drill so it stays cool. Also, use low rpm and just enough pressure to let the bit have time to do the cutting. The cutting angle of the bit (flutes), is the secret. The harder the material, the flatter the cutting angle on the bit you will need. For really tough cutting jobs, I use a cutting angle of 165 deg. (that is nearly a flat end) You will need a pilot hole.......which you already have :-)
Make a small wooden "V" shaped tray and a jig to hold it..... so you can position the bit at the appropriate angle to a bench grinding wheel to enable you to grind both cutting flutes of the bit to the same angle and keep the point centered. You will need to sharpen the bit multiple times, but go slowly, moderate rpm, keeping the bit oiled and cool and with a bit of patience, you can drill a hole through almost anything. (buy good bits......nothing made in china....:-) :-)
When the bit stops cutting, dont press harder. Stop and resharpen it.

When sharpening bits on a grinding wheel, dip them into a cup of water every couple of seconds. If you discolor them from heat by grinding too long with too much pressure, the temper of the bit is destroyed and its into the trash can and try again with a new bit.

Earl

[quote="rongant"]
I have tried about a dozen drill bits... I just keep getting to the point where it will just NOT drill in any further. The hole I drilled is only about a 1/4" deep if that... so no extractor in the world is gonna work now... plus it's a hack job... it's not even a nice centered perfectly straight hole at that.

[Anonymous]

been there

What I would do is go in the phone book and find some one that does TIG welding, load the bike up in a truck, or throw the exhaust back on, what the welder will do is weld a smaller stud to the broken one and with the concentrated heat it can be grabed with a pair of vise grips and screwed out, I have done a lot of fixes with this method cases heads you name it

[Anonymous]

I've heard a few concerns about welding around aluminum though ...
I'm no welder by any means, but isn't it risky welding aluminum?

[Anonymous]

weld

You're not really welding the aluminum, just next to it. The constant heating and cooling also helps loosen the bolt.
Something similar to the method I used to remove two of my busted bolts....Mike

[AOD]

i have a bolt broke off in my head...it's been okay using just one. my old 550 was that way for a while..it had a bolt broke off in when i got it.

if you have to leave it, you should be okay. just a heads up.

~AOD

[Anonymous]

I welded a nut onto a broken off stud and with the concentrated heat, came out relatively easy. Once you have the nut welded onto the stud, work the nut/stud clockwise and counter clockwise to break it loose.

[Anonymous]

Don't get me wrong... the bike isn't really loud, and rarely backfires or anything... it's just that I want it to perform as best as possible...
A guy in town here with a DYNO said that would be the first thing he would recommend before bothering with a DYNO run...

Also, it's not a broken stud, it's a broken bolt ... so there's nothing to really weld a bolt to...


I'm going to check into getting drill bits with shallow angles going on ... see if anybody in town has something specialty like that!

thx so far guys!

[DMPLATT]

If the other person broke a drill or an easy out, ouch.
Try to find good quality Cobalt drill bits and use some type of heavy cutting oil. AND SHOW LOTS OF PATIENCE AND LOW RPM's ON THE DRILL!!!!!!!!!!

The idea of the template is also an excellent idea. It will help keep the drill from Walking off the broken tool. But many people don't have access to the machinery. I'm a quality manager at a machine shop, so I can do it on a CNC or Bridgeport. Fringe benefits I guess

Regular HSS drills will just pis$ you off and won't cut much, probably just break. Won't go thru broken easy outs or drill bits. Cobalt is your best bet.

I too have a broken bolt, but am leaving it for now. It runs great, but it does backfire when letting off of heavy throttle. I assume that's what causes it, but my plugs were all clean and she starts right up. I'm leaving it.

Good luck and please let me know how you do. I'm very curious as to what I can expect.