carbs for 850

My Commando came with a vintage Sonny Angel (worth googling if you don't know him) 2 into one manifold and an old Mikuni. I could never get the Mikuni tuned right (and a Jap part on a Brit bike irks me), so I replaced it with a single Amal MkII with the new stay up float and K&N filter, which works great for my casual style of riding.
I have acquired the proper manifolds and airbox parts and have spare Amal Mk1 carbs and parts to convert to the stock setup. Is there any advantage to converting back to the dual Amal setup with Amal Premiers (or at least their anodized slides), or am I asking for more trouble than it's worth? I have never had trouble with the dual Mk IIs on my '79 Triumph Bonnevilles; has anybody tried this setup?

I have been swearing by a single carb setup for awhile. It was and is a good setup for me. When the new Premiers came out I felt I needed to give them a chance and I sure am glad i did. Great carbs.

I ran a single markII once and for me it was the weakest of all the single carb setups. So, Mr. Casual rider, you will have a real issue with keeping your riding casual with such a profound increase of performance.

For me the temptation is too hard to resist. The is your fair warning. I seem to have an increasing need for better protective gear.

Are you running a single concentric? If so, let me know the specifics and I can give it a try.
The more protective gear I started to wear, the faster I would go. After riding my Hinkley Trophy way too fast too often I sold it. I outran a motorcycle cop once to avoid the automatic night in jail. I also passed 35 cars in one pass on a 2-lane road on it. Hey, I'm closing on 60. I'm almost old enough to be riding a Gold Wing. Then I picked up a Laverda triple last year....

christulin said:

Are you running a single concentric? If so, let me know the specifics and I can give it a try.
The more protective gear I started to wear, the faster I would go. After riding my Hinkley Trophy way too fast too often I sold it. I outran a motorcycle cop once to avoid the automatic night in jail. I also passed 35 cars in one pass on a 2-lane road on it. Hey, I'm closing on 60. I'm almost old enough to be riding a Gold Wing. Then I picked up a Laverda triple last year....

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No way, I was running a Mikuni TM40-6 pumper carb earlier this year and now the Premiers. The single MKII was about 3 years ago. I was weak.

My dad had a '66 ('67?) Triumph 500 Daytona (beautiful bike!) that had twin Monoblocs on it. By the dealer's urging, he installed a two-into-one manifold from a Bonneville, and used one of the stock Daytona carbs. According to my dad (I was six, but already very in tune), the bike ran just as fast on the top end, but was much more responsive at the lower rpm range. They even had to lean it out slightly. Best of both worlds! If you think about the intake sequence of the parallel twin with a 360' crank, you can see that a twin carb setup will have air being pulled from any one carb for one-quarter of the time, then sitting idle for the other three-quarters. Carbs don't like pulses; they prefer a steady draw. Since a carb has to be large enough to fill its cylinder during that one-quarter time, why not let the other cylinder draw from that same carb in its spare time? Go with the single!
As for your Mickey carb, I really like them, but, as with Holley carbs on car engines, you can change everything about them. They better be pretty damn close to start with, or you'll get lost in a sea of brass jets that's hard to recover from. I took a pair off a couple of two-stroke dirt bikes (I worked in a bike salvage yard) for my 650, and literally spent an entire summer jetting them. NOTHING was the same from when I first got them, and I sure learned a lot about how all the circuits interact. I wouldn't give up on the Mickey just yet... Nathan

Between swap meets and an estate sale, I have boxes of monoblocs, concentrics and MkIIs with an assortment of jets, needles and slides, so I'll stick with Amals. I haven't tried the Premiers yet, but it sounds like Burlen has finally made the changes that should make the concentrics less troublesome but still look original.

Just think when Norton Commando's came out they were classed as HI PERFORANCE motorcycles, to put a single carb set up to me is just staving the motor for what it was ment to be HI PERFORMANCE, if you need to replace your old carbies, keep the dual carbie set up as that was what it surpose to be, I replace my orginal Amals in the 80s, they were still good till about 3 years now I decided to replace them with Jim's Flatslides when I had some spare cash, I have slowed down a bit as I get older but what a feeling and buzz I get when I do open the throttle and instant response and then when the SS cam kicks in, it makes me feel young again, enjoy your Norton the way its surpose to be, even if you don't need hi revs, it is always good to know if you get into trouble and you need that instant squirt to get you out of it, I could never stave my Norton for gas, but mine you my motor has some surprises inside it that surprise a lot of moden bikes riders.

Ashley

Since the Norton has become my daily rider, I'll leave it be for now. Next winter may be a good time for a more complete rebuild and go with the dual carbs.