Another $%(^#$ Exhaust Bolt Thread

[Sweaburg]

Hey everyone...just in time for spring I stripped one of the header bolts on my 850. I'm not sure how it happened either. I loosened off the bolt no problem but as it came further and further out it got tighter and tighter and then....

it pretty much started spinning in circles

The bolt will neither turn all the way in or come all the way out anymore and it now has a hell of an exhaust leak when its running!

I searched the forum but couldn't find anyone who has had this specific problem. What are my options here? I have a bad feeling this is going to get expensive....

[earlfor]

I would try turning it out until it tightens. If it tightens, then I would consider cutting the bolt head off and using it as a stud. Put a nut on it to hold the exhaust pipe on and call it a day.

Earl

[EZ OUT]

I assume that you were trying to loosen the bolt to get the headers off??
If you have to take it off, you might try purposely stripping the head bolt holes by alternately pounding it in the pulling it out. Retap to a larger size or heli coil after you removing the offending bolt. Mine broke off so I drilled it out and re tapped the hole.

[bwringer]

Part of the threads in the head and/or the bolt have stripped out.

Actually, you're very lucky -- the bolt hasn't broken! That's amazing!

What you need to do is find a way to apply outward pressure on the bolt while turning it. Get creative with crowbars, prybars, etc. Make sure you squirt some of your favorite panther whiz in there. At some point, what few threads remain on the bolt will catch the remains of the threads in the head and you'll be able to remove the bolt.

DO NOT leave the bolt in there. The fickle gods of aging parts and metallurgy have been very kind to you by giving you this one last chance to remove the bolt.

Once the bolt is out, understand that the threads in the head are totally stripped. Luckily for you, I believe the holes are accessible on 850s (they are on my 850 anyway), so inserting an 8mm helicoil should be easy from there, as long as you don't go too deep.

If you haven't already, take this chance to clean the other threads in the head with a tap and plenty of lube and then replace all eight bolts with stainless-steel allen head bolts, liberally coated with high-temp anti-sieze. I make it a point to recoat mine once a year.

[Sweaburg]

I assume that you were trying to loosen the bolt to get the headers off??

Yes.

Thanks for your suggestions guys. I'll see what I can come up with now that I've cooled off a bit! I'll post my progress after I get a chance to work on it.

Sweaburg

[Sweaburg]

Actually, you're very lucky -- the bolt hasn't broken! That's amazing!
olt in there. The fickle gods of aging parts and metallurgy have been very kind to you by giving you this one last chance to remove the bolt.

Once the bolt is out, understand that the threads in the head are totally stripped. Luckily for you, I believe the holes are accessible on 850s (they are on my 850 anyway), so inserting an 8mm helicoil should be easy from there, as long as you don't go too deep.

Well my luck ran out! The bolt has now sheared, so I guess I'll have to do some research on using a helicoil. I'm not sure I'll feel comfortable doing that myself so I'll have to look into it and decide whether or not to take it into a shop.

If I decided to have it done professionally will I have better luck at a machine shop or will most motorcycle mechanics do this for me?

Thanks,

Sweaburg

[EZ OUT]

Actually, you're very lucky -- the bolt hasn't broken! That's amazing!
olt in there. The fickle gods of aging parts and metallurgy have been very kind to you by giving you this one last chance to remove the bolt.

Once the bolt is out, understand that the threads in the head are totally stripped. Luckily for you, I believe the holes are accessible on 850s (they are on my 850 anyway), so inserting an 8mm helicoil should be easy from there, as long as you don't go too deep.

Well my luck ran out! The bolt has now sheared, so I guess I'll have to do some research on using a helicoil. I'm not sure I'll feel comfortable doing that myself so I'll have to look into it and decide whether or not to take it into a shop.

If I decided to have it done professionally will I have better luck at a machine shop or will most motorcycle mechanics do this for me?

Thanks,

Sweaburg

When I broke a header bolt off I took my bike to the local shop. They advised me that I should try first to drill it out on my own, then if I screwed up the threads, take it to a shop. They charged $50.00/lhr labor. and they couldn't guarantee it would take less than an hour.
So I read volumes on this site from those who have gone before and decided to go for it. I started by punching a dimple in the old bolt as close as possible to dead center. Then I measured the bolt and added the depth of the collar clamp to that and marked my drill bit with electrical tape so I didn't accidently drill too deep. In my case, the old bolt was so thoroughly fused to the threads that when I tapped it out I was able to use the same size bolt as the original. If you do this you will want to pay close attention to the angle that the bolt enters the head to make sure you drill on the same line as the original hole. All, in all it worked out for me quite nicely.