Old ham can air cleaner fit new premiers?

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Joe Schlaberdowski

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In the boxes I got with the Commando I bought several years ago were the old concentrics and the old ham can air cleaner. I have a vm-34 mikuni on it (came with). But had tuning problems which I dealt with. Came out alright. Lot's of fiddling, but that's what I enjoy. Anyway, I was considering new concentrics (and I know all the arguments, Mikunis vs Premiers. I've read about it on this site so often.). Or even rebuilding the old ones. But if I do go with new Premiers, will it be an instant fit? I'd like to chrome the air cleaner lattice and front and back plates as well. I think that would look really nice.
 
Yes, sort of... You will need two each of part number 033027 Adapter, Airfilter, 900 Amal. See Old Britts Carburetor Mountings, Air Filter and Fuel Line
Group 12, part 18. My premiers did not come with those adapters. The original Amals came with those mounted and I just transferred them but if you don't have the original Amals, you may have to purchase a pair of those to fit to the Premiers. Check to see if the current premiers ship with them and if not, order a pair. The rubber seal from the plate to the carb fits around that adapter.
 
As I understand it, the carb adapter sleeve is a a Norton part, not an Amal part.

Old ham can air cleaner fit new premiers?

https://andover-norton.co.uk/en/shop-details/14983/carb-adaptor-sleeve

They do not ship with new Premiers, but are available from your favorite Norton parts supplier.


As @MexicoMike stated, the only other thing you will need are the rubber connector hoses

Old ham can air cleaner fit new premiers?

https://andover-norton.co.uk/en/shop-details/15875/carb-connector-hose-06-0671-
 
Joe Schlaberdowski said:
In the boxes I got with the Commando I bought several years ago were the old concentrics and the old ham can air cleaner. I have a vm-34 mikuni on it (came with). But had tuning problems which I dealt with. Came out alright. Lot's of fiddling, but that's what I enjoy. Anyway, I was considering new concentrics (and I know all the arguments, Mikunis vs Premiers. I've read about it on this site so often.). Or even rebuilding the old ones. But if I do go with new Premiers, will it be an instant fit? I'd like to chrome the air cleaner lattice and front and back plates as well. I think that would look really nice.
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You can buy those front plates in stainless and filter screen too. Cheaper and looks great.
 
Just fitted new premiers and slimmed down ham can looks and goes a treat, well pleased.
 
ninja said:
Maybe, maybe not, too much rattle about filters, will check plug colour, I really don't see that an inch will upset the motor IMHO.
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So many factors. The filter surface area (small ham can, big ham can -- seems funny to me to say it that way), filter material, maybe even configuration. Now, in my younger days, when killing myself with one stupid stunt or another meant little to nothing, oh that extra bit of power above the proverbial ton was very important. Now, not so much. I don't even know if the "restriction", if I might call it that, is a linear function of engine rpm or not. So maybe there is no detectable difference between ham cans (lol) below a fairly high rpm, just at the top. So me thinks I'll buy one -- or the other. But then again, I gave up on "Joe Schlaberdowski king of the oval track" fantasy a long time ago.
 
Consider that the perforated metal screen of the Ham Can is a fixed "restriction" on the filter, much more so than the type of filter being used. The perforated ham can probably has (I'm not going to try and figure it out) 1/2 of it's area "closed" due to its construction. What I'm saying is that the relatively large filter unit isn't, in operation, large at all as far as the engine is concerned because 1/2 of the perforated screen is "closed." Whether going to a smaller ham can matters, I have no idea. It would take a dyno to determine it though a spark plug chop test might give a decent idea - observing to see if the plug reading goes richer than it was with the stock ham can.

FWIW, I had properly jetted Amals with the OEM Ham can. I installed long velocity stacks with no screens/filters. I had to go 2 jet sizes richer to keep the plug reading in the same range. Putting screens on the stacks made the mixture richer than it was with the ham cans using the original jets. ;) (Totally stock engine)

The screened stacks were more "restrictive" than the OEM Ham can.
 
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MexicoMike said:
Consider that the perforated metal screen of the Ham Can is a fixed "restriction" on the filter, much more so than the type of filter being used. The perforated ham can probably has (I'm not going to try and figure it out) 1/2 of it's area "closed" due to its construction. What I'm saying is that the relatively large filter unit isn't, in operation, large at all as far as the engine is concerned because 1/2 of the perforated screen is "closed." Whether going to a smaller ham can matters, I have no idea. It would take a dyno to determine it though a spark plug chop test might give a decent idea - observing to see if the plug reading goes richer than it was with the stock ham can.
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Why not remove the metal screen and see if it makes a difference? Not clear to me what purpose it serves anyway - appearance maybe.
 
MexicoMike said:
Consider that the perforated metal screen of the Ham Can is a fixed "restriction" on the filter, much more so than the type of filter being used. The perforated ham can probably has (I'm not going to try and figure it out) 1/2 of it's area "closed" due to its construction. What I'm saying is that the relatively large filter unit isn't, in operation, large at all as far as the engine is concerned because 1/2 of the perforated screen is "closed." Whether going to a smaller ham can matters, I have no idea. It would take a dyno to determine it though a spark plug chop test might give a decent idea - observing to see if the plug reading goes richer than it was with the stock ham can.

FWIW, I had properly jetted Amals with the OEM Ham can. I installed long velocity stacks with no screens/filters. I had to go 2 jet sizes richer to keep the plug reading in the same range. Putting screens on the stacks made the mixture richer than it was with the ham cans using the original jets. ;) (Totally stock engine)

The screened stacks were more "restrictive" than the OEM Ham can.
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That result, from putting screens on the stacks, is a bit of a surprise. I'd bet few would have expected that. The stacks are designed to give non-turbulent flow (smoothly shaped with some kind of exponential curve) and the disruption and obstruction of the screens so close to that stack spoils all that work by the designer. Just a question I don't really expect to be answered is if you had a large airtight box chamber that had two screened openings on one end the same size as those screens that were on the stacks you spoke of and you had the two stacks on the other end, would the result be the same. Wondering about obstruction to an airflow as in a restriction of an opening vs causing reduced flow due to turbulence.
 
Just to put a fine point on something that's undoubtedly not worth it, maybe the distribution of the openings between, or through the grill of the ham can reduces turbulence -- just a gentle flow into the ham can chamber. It looks like the sum total of the open area through the ham can grill is far larger than the opening from the ham can to the carbs anyway. Which might not be the case for a velocity stack with a screen covering, one way or the other. But I must admit it looks cool with the screens on those stacks.
 
On my Commando (Fastback tank/side covers) you can't see the stacks at all unless you kneel down next to the bike so the "visual impact" of the stacks is non-existent to anyone casually looking at the bike. :(

Re air filters/turbulence: Early in my auto drag racing/engine building days we found several cases where an engine that produced X HP on the dyno did not produce the numbers at the drag strip that the HP/weight should have produced. Fooling around a bit we discovered that the airflow into the carb via the hood scoop as the car increased speed was causing a problem with turbulence into the carb. Since typically drag cars didn't use air filters, we decided to install a large air filter - actually two round, OEM-type paper filters stacked on top of each other. Performance increased to mimic the dyno numbers!

So...a stationary engine on a dyno and an engine running down the track can react very differently based on how air is "fed" into the carb. For years now, most performance cars have some sort of airbox that is specifically designed to ensure optimum air delivery. In most cases, removing the airbox to "improve" performance will actually reduce it.

I don't think the ham can be considered an airbox in the modern sense but Norton may have done experiments with various air filter setups to find the one that produced the best performance engine...or maybe not! ;)
 
Why is it you never see intake ports on the front side of motorcycles? Seems this would aid intake pressures by ram air affect at speed.
 
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