I have a Commando which uses bronze exhaust roses. I have a spare set of bronze roses which I can't use as the thread diameter is slightly larger.
The thread pitch and internal hole diameter is the same as on the standard items.
Does anyone know if these are from another model (or make even) or are they 'specials' that someone has had made after their originals have rattled loose and wrecked the smaller std. thread in the cylinder head?
For pics see items for sale section.
Two possible answers here.…
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Phil, thanks for the info.…
Phil, thanks for the info. I'll have to have a closer look at my Model 18 to see if my larger exhaust nuts are a match.
Previously Phil Hannam wrote:
Two possible answers here. Firstly, some of the singles used a similar exhaust nut (rose) that was a slightly wider diameter.
Secondly, and more likely, back in the late 70s, There was an easy fix for any Norton Heavy Twin cylinder head that had stripped its exhaust threads. This was to recut the thread to the next size up and fit oversize nuts. A South London firm called BLR Engineering used to specialize in this procedure for £25 including brass replacement nuts. The advantages of this fix was that the nuts expanded roughly at the same rate as the aluminium exhaust ports and so once tightened, they rarely came loose. For extra dosh you could get the nuts chromed or nickle plated to look similar to the originals. The only drawback was the standard exhaust gaskets were now too small to fit the ports properly but by purchasing 2 for a Norton single this problem was overcome.
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Two possible answers here. Firstly, some of the singles used a similar exhaust nut (rose) that was a slightly wider diameter.
Secondly, and more likely, back in the late 70s, There was an easy fix for any Norton Heavy Twin cylinder head that had stripped its exhaust threads. This was to recut the thread to the next size up and fit oversize nuts. A South London firm called BLR Engineering used to specialize in this procedure for £25 including brass replacement nuts. The advantages of this fix was that the nuts expanded roughly at the same rate as the aluminium exhaust ports and so once tightened, they rarely came loose. For extra dosh you could get the nuts chromed or nickle plated to look similar to the originals. The only drawback was the standard exhaust gaskets were now too small to fit the ports properly but by purchasing 2 for a Norton single this problem was overcome.