On The Bench - Norton Carb Spacers

It's the holiday season here at Solo, but time off from "real" work, doesn't mean I'm not doing work on the motorbikes. Quite the opposite really. As it's great to have a stretch of time to make some progress without the pesky interruption of my job getting in the way. The plan is to knock out all of the existing small projects over the course of the next 10 days.

First up is a set of standard Norton carburetor spacers for all Dominator and Atlas models. I'm looking to convert my Atlas back to twin carbs over the winter. And while finances will dictate wether that happens or not, I can at least prepare all the bits, so that if enough money gets saved up, and I purchase the carbs, everything will be ready to mount up.

I've enjoyed the single Amal MKII carb on my bike for countless years, and while it's not original, my main reason of keeping it on the bike, is the simple fact that I'm infatuated with the very rare Sonny Angel 2 into 1 cast aluminum manifold (more on that later). But I really would like a more traditional set up with the twin monobloc carburetors.

These spacers were found much like all the other parts I find; discarded and basically forgotten about. After shelling out $30, they showed up in the mail, and as expected, were filthy. They both were stripped of the rubber balance line, which got tossed in the trash. I pulled out the threaded fittings and everything got a wash in the sonic tank. After that, it was time to sand out decades of screwdriver gouges and who knows what else. This first photo is a side by side of one that's been finished and one that was clean, but not yet sanded or polished.

After about two days of carefully sanding and polishing, they were ready to be put back together. One major thing of note is the fact that one end of each manifold is slightly more squared off, and doesn't really follow the profile of the carb flange. Obviously, both left and right pieces were from the same casting, and you'd think someone at Norton would have had the smarts to face those two flats toward the inside. For one, you wouldn't see the flats, and more importantly, the inside studs are a very close mounting configuration, so having both flats facing in, would have made sense. But, the threads for the balance pipes would then be on opposite sides if mounted that way. And of course, that would simply look stupid. So, the only solution is to carefully sand the corners around the flats, and re-profile them to better match the carburetor flange. It's that simple task that takes the longest time. Most people wouldn't care, or even notice, but it's one of those things that would surely bug me every time I looked at it. So the extra time and work is well worth it.

Finished spacers both sanded and polished, and rubber fuel line with braided cotton jacket added to the balance tube. When mounted, the balance tube is in a U shape, and can be mounted either top or bottom to your choosing.

I can't stand hose clamps, so I refuse to use them. They're ugly and bulky, and simple don't look right. Since the balance hose doesn't need to come off, I use safety wire to keep them snug to their fittings. It does a great job and looks a whole lot better than hose clamps. It's also completely tucked out of the way and I think it's just a nice finishing touch.

On to the next project.