Exhaust nut question

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Comstock is probably the best repair but, I could repair it myself if someone made oversize nuts and supplied or "rented" a tap to recut threads. Maybe while still in the frame. Is there Nobody supplying these?
 
mean gene said:
Comstock is probably the best repair but, I could repair it myself if someone made oversize nuts and supplied or "rented" a tap to recut threads. Maybe while still in the frame. Is there Nobody supplying these?
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New threads must be cut on a lathe, no tap there. Most machine shop can perform this perfectly in a short time frame. OS nuts just require 1/16 inch larger diameter than standard ones. The exhaust ports are not weakened and no multiple expansion rate between different materials (steel stainlesse steel, bronze, aluminum)
 
Other than Mr. C., whom appears over booked currently, is there a shop in Canada/US that can make up suitable insert sleeves for problematic, already oversized ports?
 
Tornado said:
Other than Mr. C., whom appears over booked currently, is there a shop in Canada/US that can make up suitable insert sleeves for problematic, already oversized ports?
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Jim sells his bronze inserts, IIRC. See if you can buy a set and have them installed in the GWN.
 

cylinder head exhaust threads stripped

first of all, a huge thanks to all on this amazing forum. i recently acquired a 1972 norton commando roadster and found this site. great folks and great info in here. the bike is basically in pristine condition. I've had to fix a few odd things here and there but nothing major. so far…...
www.accessnorton.com www.accessnorton.com

documentary- exhaust thread repair

What do you do when the welded in insert comes out. Here's the insert , you can see the narrow ring of weld that held it. It left a hole to big to thread or do much with except weld So after an afternoon of weld a little and let it cool you end up with aluminum were ther was none. boring and...
www.accessnorton.com www.accessnorton.com
 
Got an exhaust header spring rigged up with a bit of safety wire now (as seen in other threads on this topic). Also applied a little penerating type Locktite (green) around edges of nipped up rose nuts...just to help keep them in place. Will make some test runs to see how well that all holds up. Might be able to string this season out before needing the head off for machining.
 
Let's get this party started...

Engineering compromises leading to exhaust threads stripped (2012)

Best I can see is, the exhaust threads being a problem area, is the result of multiple engineering EVOLUTION compromises. In the beginning, the head was cast iron and the threaded attachments probably worked just fine. Then the thread (head) material changed to softer aluminum... and they...
www.accessnorton.com www.accessnorton.com

:cool:
 
Sergio said:
New threads must be cut on a lathe, no tap there. Most machine shop can perform this perfectly in a short time frame. OS nuts just require 1/16 inch larger diameter than standard ones. The exhaust ports are not weakened and no multiple expansion rate between different materials (steel stainlesse steel, bronze, aluminum)
Click to expand...
You can get a tap the size of the exhaust thread but is over $300 and was going to buy one to fix up the thread on a motor I was building for a mate, my 850 threads are still good as my motor is hard mounted in the Featherbed frame, seems like the problem with buggered threads are from rubber mounted motors and exhaust and lose flanges after 40 years in the Featherbed frame I have never had my exhaust rose come lose, I have no locking rings or anything just the rose, flange gasket and one muffler mounting bracket on each exhaust.

Ashley
 
Hot exhaust gases flow more freely when oiled lessening the vibrational/friction impact on the threaded nut/head contact area so ample lubricant is essential.............. Stop me before I kill again. I honestly couldn't help myself.... Still laughing over the anti-wetsumping comment.
 
Tornado said:
Got an exhaust header spring rigged up with a bit of safety wire now (as seen in other threads on this topic). Also applied a little penerating type Locktite (green) around edges of nipped up rose nuts...just to help keep them in place. Will make some test runs to see how well that all holds up. Might be able to string this season out before needing the head off for machining.
Click to expand...
Welp been three multi-hour long rides now since fitting the safety wire & exhaust spring arrangement with some green locktite drizzle for good measure. No signs of nut loosening. Previous few rides had left side shaking loose more than once in even after heavy cinching up with long lever wrench and whacks with big persuader.

Dare I say she's done?
 
My bike has these kind of nuts (which annoyingly have odd spacing between the "Big fins") and although fully tightened the right pipe still had some movement. I've taken it apart and the threads are perfect, but to me it looks as though the threaded part on the nut could do with being a few mm longer, as it seems to bottom out under the fins but still leave about a 4mm gap inside when tightened without the pipe inside it. I'm thinking of using two steel crush washers instead of one. Can anybody think of a reason why not to?

Exhaust nut question



I quite like the idea of drilling and tapping one of the big fins and putting a pointy grub screw through it to ensure it won't move, as described here..


Exhaust Nut Option

Due to the high mounting of my race bike pipes and being stubborn about using standard exhaust nuts with lockwire, a friend had had his modified by an engineer friend for his Roadster in the past so I decided to copy this option as it just utilises all the standard components I found a new set...
www.accessnorton.com www.accessnorton.com

Waste of time ??
 
Nuthin wrong with using two crush washers, lots of folk do that.

I‘d just expect there to be twice as much crushing to do, so keep twice the eye on tightening praps.
 
cliffa said:
My bike has these kind of nuts (which annoyingly have odd spacing between the "Big fins") and although fully tightened the right pipe still had some movement. I've taken it apart and the threads are perfect, but to me it looks as though the threaded part on the nut could do with being a few mm longer, as it seems to bottom out under the fins but still leave about a 4mm gap inside when tightened without the pipe inside it. I'm thinking of using two steel crush washers instead of one. Can anybody think of a reason why not to?


I quite like the idea of drilling and tapping one of the big fins and putting a pointy grub screw through it to ensure it won't move, as described here..


Exhaust Nut Option

Due to the high mounting of my race bike pipes and being stubborn about using standard exhaust nuts with lockwire, a friend had had his modified by an engineer friend for his Roadster in the past so I decided to copy this option as it just utilises all the standard components I found a new set...
www.accessnorton.com www.accessnorton.com

Waste of time ??
Click to expand...


Per dynodave:

For info there are 3 norton exhaust nuts.
The basic 3/4" deep small fin 1949-1972 Though they were carried under evolving part #
One year 1973-750 Big fin 3/4" deep threads
850 1/2"effective threads Big fin
ALL NHT ports were 3/4' deep

Exhaust nut question


You appear to have a version of the shorter type, for use with exhaust collets that fit in the header between it and the crush washer?

andover-norton.co.uk

Andover Norton - EX. PIPE RETAINING COLLET (06.3990) - 06.5260

EX. PIPE RETAINING COLLET (06.3990)
andover-norton.co.uk
 
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