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Sorry if this is not the right forum to post this, but I've recently started taking apart the top end on my 2008 ktm exc-r 450. I was able to loosen 3 out of the 4 bolts that hold the cylinder head on and when I got to the last one (front right shown in the picture) the inside rounded out. :( As you can see from the picture its pretty close to the side of the engine so nothing can fit around the outside of it. I tried using a star-head to get a little more grab on the inside of the bolt head but no luck. I'm trying to figure out what my options are before I make anything worse. I've been told I could cut the bolt head off, but if I do wont the threads inside still be holding the cylinder head down?? Maybe a stupid question, since from looking on the oem parts finder it looks like the threads dont start until their into that bottom part of the engine. I've also head of tack welding a bolt on top to remove it, but not sure how hard thatd be to do with such little space. Are there any other tools or tricks to getting this thing out before resorting to those last ditch efforts?

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Find the next largest Allen wrench that won't quite fit in. You can grind a slight taper on it until it just tries to start in the original Torx. Now drive it in with a hammer. It might be best to cut off a length of a regular "L" shaped Allen wrench and put that piece in whatever size socket fits it. Then you can put an extension in that socket and get it to a position you can hit it. Keep all the downward pressure on it you can while you try to loosen it.  Worst case if this fails and given its location I would probably take a die grinder with a burr and grind the head off. It wouldn't take too long to do it that way. After that you would have to lift the head up as far as you could and screw the bolt out with pliers or pull the engine to get the head completely off and get access to remove the remaining bolt. Patience is key - it can be removed - just a matter of the method. Clay. 

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You can try what he said or load bike go to local muffler shop have them weld (mig) the head of a new bolt to old one. 30 years in a Steelmill as a Millwright we ran into this crap all the time. Dosent have to be welded all the way around. 

That or colbalt bit and ez out

-Sarge

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Yep - that's another option that'll work. If you can get to it with a drill bit you can drill the head off the bolt also. Not sure about the bolt diameter under the head - they're usually 8 - 10 mm so a 11mm or 7/16" would work. Clay

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You can dremel a flat slot in the head of it and use a large flat blade screwdriver to back it out.

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Should clean that stuff up before tearing apart

 

 

were you using a standard allen or with the ball on the end, Id try both

Edited by Spud786

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Weld a bolt to it works well, but all that dirt getting in motor is a bigger problem wash it first.

Edited by allout48
spellig

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12 hours ago, nuity5 said:

Find the next largest Allen wrench that won't quite fit in. You can grind a slight taper on it until it just tries to start in the original Torx. Now drive it in with a hammer. It might be best to cut off a length of a regular "L" shaped Allen wrench and put that piece in whatever size socket fits it. Then you can put an extension in that socket and get it to a position you can hit it. Keep all the downward pressure on it you can while you try to loosen it.  Worst case if this fails and given its location I would probably take a die grinder with a burr and grind the head off. It wouldn't take too long to do it that way. After that you would have to lift the head up as far as you could and screw the bolt out with pliers or pull the engine to get the head completely off and get access to remove the remaining bolt. Patience is key - it can be removed - just a matter of the method. Clay. 

I've some experience in such disasters, and this would be my first strategy.

Someone else mentioned cutting a slot with a dremmel. I've done that too, but it is very difficult to get enough torque to break it loose, unless you one of the old hammer operated impact drivers.

 

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Quote

Should clean that stuff up before tearing apart

Quote

Weld a bolt to it works well, but all that dirt getting in motor is a bigger problem wash it first.

Yeah...you really need to clean that area up. Personally I would never have started that project with a bike that dirty.

Good luck with the bolt...I'm sure you'll find a way.

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Cutting a slot then a hammer activated impact driver might do the trick.  Actually the hammer activated impact driver might work with the next size up  allen or torx driver.  

https://www.amazon.com/Lisle-29200-Hand-Impact-Tool/dp/B0002NYDRG/ref=sr_1_2?ie=UTF8&qid=1488823124&sr=8-2&keywords=hammer+impact+driver
 

Edited by sirthumpalot

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Do it the Steelmill way, one guy holds a cold cut and another wacks it with a 8 or 12# sledge. Then paint it black so the boss can't see what you did, Caveman mechanical at its best. 

Btw I'm only kidding but guys out at the mill that's how they operate, won't move get a bigger hammer. 

Beating on it imho is a bad idea good way to crack that case. Either way you do it heat the area first, steel and aluminum love to seize to each other, when you reassemble use neverseize, copgraph or high temp nickle loctite antiseize on threads. 

You might drill right thru the side, that socket head is Grade 8 so a cobalt 118 degree bit is needed then insert a hardened steel or tool steel rod even a good snap on screw driver thru hole just to crack it loose.

Edited by Bill Sanders
Typo

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Which ever method you use, first apply a 50-50 mix of automatic transmission fluid and acetone (or MEK) a few times and let it soak it up for a while to loosen it up.  The solvent thins the oil and carries it deep into the threads that are bound up.

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For the record; the hammer operated impact driver is not for beating it silly with a bigger hammer, lol.  You normally don't have to whack it hard at all, but the energy from the hammer helps keep the   bit in place while it turns.  And it might help to wedge the next size up bit  into the rounded hole while at the same time turning it. IMHO, it's the least invasive next- step.  

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