Stripped exhaust threads, how do you fix them?

[Farmer Dan]

Started my '72 Eldorado and let it idle for a few seconds when I heard a loud "POP" and the right exhaust nut blew clean out of the head.  I have never seen or heard of this happening before.  I have heard of guys over tightening them and stripping them but never seen the bike do that.  Short of buying a new head is there anyway to fix the threads in the exhaust port? 

[Lee Davis]

Whew... That is a tough one. I ran a Porsche and VW engine remanufacturing business for quite a few years and we replaced broken studs all the time. But, the exhaust nut on a Guzzi is quite a different breed. Here is a posting: http://wildguzzi.com/forum/index.php?topic=90094.0 . This fellow charges $175 per fix, to weld it up and cut new threads. That seems a bit steep (although I don't blame him for the cost... it is a laborious operation). I would find a replacement head, I think. I have bought them for as little as $50 each on Ebay... but I am sure that you can find them for perhaps $100, although infrequently. If you have no luck, I have about a dozen 750 and 850 heads sitting on the shelf, and would be happy to send you one, if you send me your original for comparison (there is a modest variety in the different heads). No charge.   Lee Davis  copy@radarcarve.com

[Tom]

One of the guys did a fix without replacing the head.  If I remember correctly, if you want the looks then replace the head.  If your bike is more utilitarian.  It would involve drilling your head and using bolts to mount the header pipes.  There was a thread on the subject.  Maybe you can find something on Greg Bender's website.

[Lee Davis]

Here is a shot of the two types of heads. To add studs as the mounting choice, there has to be the cast bosses to either side. I have seen threaded ports with untapped bosses, but the most common type does not have the castings. 

[Tom]

That's it.  Personally if you go to all that work just replace the head. 

[Lee Davis]

This comes from Gregory Bender: Fortunately, Gordon and Rick at MG Cycle told me about Competition Cycles in Butler, WI. For USD $75.00 plus return shipping, they repaired my threads. Essentially, they drilled out my old threads, and welded in a new insert. They cut the threads to precisely match your exhaust nut, so be sure to send them the exact nut you plan to use - do not assume that the stock exhaust nuts are precisely the same as the replacement. I am very happy with the appearance of the repair and have had no trouble with it.

Competition Cycles
 5081 North 124th Street
 Butler, WI. 53007
 Phone: (262) 373-1122

[Chuck in Indiana]

This might be in the "Tips" book..  but one of the nastiest bodges I've seen on an old Guzzi was this:
Just pack muffler cement around it, and drive 3 wood screws through the casting into the pipe. "That'll hold that sucker on there, Jethro.." 

[Idontwantapickle]

This comes from Gregory Bender: Fortunately, Gordon and Rick at MG Cycle told me about Competition Cycles in Butler, WI. For USD $75.00 plus return shipping, they repaired my threads. Essentially, they drilled out my old threads, and welded in a new insert. They cut the threads to precisely match your exhaust nut, so be sure to send them the exact nut you plan to use - do not assume that the stock exhaust nuts are precisely the same as the replacement. I am very happy with the appearance of the repair and have had no trouble with it.

Competition Cycles
 5081 North 124th Street
 Butler, WI. 53007
 Phone: (262) 373-1122

This /\ 

It will be better than original!

Hunter

[Tom H]

To start with this will make the exhaust nut unuseable in a stock thread head. Now that you have bee warned:

If the threads are still there but a bit worn and you have a brass nut. You can use an appropriate size socket as a wedge and drive it into the exhaust nut until it fits snugly into the head.

Otherwise, as mentioned, thread repair is a good solution.

Tom

[Muzz]

Just send it to me and save yourself the hassle.

I'm good like that.

[Farmer Dan]

Here is a shot of the two types of heads. To add studs as the mounting choice, there has to be the cast bosses to either side. I have seen threaded ports with untapped bosses, but the most common type does not have the castings. 

My heads don't have a boss.  That didn't sound good did it?

[Farmer Dan]

Competition Cycles
 5081 North 124th Street
 Butler, WI. 53007
 Phone: (262) 373-1122

Got off the phone with Competition Cycle.  His estimate was $100 to repair the head.  I can get the head off and ship it to them for the repair.  Only question is how to get it back on properly.  Try to do it myself?  Trailer the bike to Wisconsin?  Find someone that can come to my shop and install it?  This is eating into my riding time!

[Rich A]

I had a head repaired by Competition. They did a good job--you could see the repair, but it was very strong.

Rich A

[Tom]

Some on the forum have offered a head.  I'd take them up on it.  Keep the old one as a spare for later repair.

[Antietam Classic Cycle]

Got off the phone with Competition Cycle.  His estimate was $100 to repair the head.  I can get the head off and ship it to them for the repair.  Only question is how to get it back on properly.  Try to do it myself?  Trailer the bike to Wisconsin?  Find someone that can come to my shop and install it?  This is eating into my riding time!

If you can take the head off, then you can put the head back on. You just need to remember to put the o-rings on the four long studs under the rocker support, orient the head gasket so the oil hole is open and retorque the head nuts several times in the first 500 miles. I can go into more detail if necessary.

[nc43bsa]

I know someone repaired the ports on one of my Commando heads by machining the old threads out and welding a pre-threaded sleeve into the port.  I don't know who did it because the head had been repaired when I got it.

[nc43bsa]

If you can take the head off, then you can put the head back on.

 :1:

I could only wish British heads were as easy to R&R as Guzzi heads.

[Tom]

 :1: on what Charlie said.  Just make sure you have a torque wrench, o-rings and gasket.

[Farmer Dan]

Well I guess that settles it then.  I want to keep the bike as original as possible so if the head can be repaired then that's what I will do.  If it's that easy to put back on then I shouldn't have any trouble.  Once I send the head out I'll order new gaskets and exhaust nuts (with the keeper).

[Tom]

 

[Tom H]

You might want to tell the repair shop what exhaust nut your going to use or better yet send it along to make sure it fits right.

Tom

[Farmer Dan]

You might want to tell the repair shop what exhaust nut your going to use or better yet send it along to make sure it fits right.

Tom

I'll get two of these:
http://www.harpermoto.com/exhaust-nut-for-v700-v7-sport-ambassador-eldorado.html
Put one on the left side and send the other with the head.
Hopefully this won't happen again.

[Antietam Classic Cycle]

There's a good chance that you'll disturb the cylinder base gasket while removing the head, so order one of those too.

Do you have the straps between the frame and header pipes and what exhaust are you running? If no straps and/or an aftermarket  exhaust without crossover, it can happen again, locking nut or not.

[Farmer Dan]

There's a good chance that you'll disturb the cylinder base gasket while removing the head, so order one of those too.

Do you have the straps between the frame and header pipes and what exhaust are you running? If no straps and/or an aftermarket  exhaust without crossover, it can happen again, locking nut or not.

I do have the straps to the frame.  Header pipes are stainless steel put on in 2015.  No cross over pipe, stock Road King mufflers.

[Tom]

   That way the exhaust system doesn't move around tweaking the header pipes and heads.

[Farmer Dan]

  That way the exhaust system doesn't move around tweaking the header pipes and heads.

So maybe two straps on each side instead of just one?

[Tom]

The Road King mufflers are heavy too.  Header pipe crossover would help or checking on the lock nut as part of your maintenance schedule.

[Tom H]

So maybe two straps on each side instead of just one?

At least on a system that is about the same weight as a stock system, one header pipe to frame clamp on each side is all that should be needed. Now the question is where to mount them? Close to the bend of the header, or closer to the muffler??? I went with just behind my floor board rear mount. Seems to work??

The best advice I've had on the header nuts: get the bike stinking hot and tighten them as tight as you can, then do it again. This seems to work as well as changing to the locking style header nut.

On the locking header nut. When I bought new headers and the new locking header nuts, the nut did not go easily past the bend in the header, had to give it a bit of gentle persuasion. So be ready to accept that.

Good luck! 
Tom

[Kiwi_Roy]

No doubt getting new inserts fitted is the best way of fixing it but that means pulling the heads off and subjecting them to s lot of welding stress.
My stop gap method is holding strong at well over 1000 miles.
2 4mm stainless screws tapped into the head.

http://i1304.photobucket.com/albums/s526/Kiwi_Roy/Quick%20Fix/Quick%20Fix_zpsal2nlxve.jpg

At least as good as this fix seen on a world traveler
http://i1304.photobucket.com/albums/s526/Kiwi_Roy/Southbound%20Loop/CIMG5131_zps067355ff.jpg

Update
Sorry fotofuckit has frozen me out

[Shorty]

You might check your timing, mixture, etc to see what caused it to spit out the nut.