Cycle Magazine's Test of Single Mikuni v Twin Amals

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Yes, it IS an expensive book. But I cannot tell you how many happy hours I have spent enjoying reading and rereading every Comando road test along with the side articles like the Mikuni conversion.
Another great book is Norton, the Racing Story
 
I too have spent many happy hours reading the Commando Gold Potfoloio original road tests, fibs and all.
I've also enjoyed the BSA A10 version of same. The fibs are even bigger in the BSA tests.
Taken at face value, the old A 10 has more top speed than most Commandos- 116 mph according to one giddy US Tester.

None of the bikes vibrated at any speed and oil leaks were unheard of.
Handling and braking were always superb with this year's model ever so much better in every way than last year's.

Right!

Glen
 
A friend of mine had a Super Rocket BSA - said it was the worst vibrating bike he had ever ridden. They were however, very quick. Had the edge on the 650 Bonneville.
 
1up3down said:
Regarding the performance differences between a single 34 Mikuni and twin Amals - I have a book with all of the Commando road tests.

In the book is a write up by I believe Cycle or Cycle world magazine detailing the installation of a Mikuni 34 and doing road acceleration comparisons between that and good pair of "well set up" Amals. The conclusion was that the Mikuni set up was faster than the twin Amals from 50-80 mph in top gear roll ons, and that after that the Amals were stronger. Also, quarter mile testing was done and the single Mikuni bike was very close to a half of a second to 3/4 of a second slower than the twin Amals. The article stated that new Amals correctly set up were good for about 4000 miles whereupon the slides would wear away enough of the body bores to promote uneven idling. In addition, the Mikuni bike did not need gas leaking/tickling and had a perfect idle without being subject to mileage deterioration as the Amals were.
IF anyone reading this can direct me to any other real world comparison road testing I would like to read it as this Cycle Magazine article is the only one I am aware of that is comprehensive to include acceleration roll ons and quarter mile testing. Personal bias, seat of pants, comments and opinions are only that when compared to actual bike to bike stop watch performance testing as Cycle took the time to present.
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Robert Shaw TN I have had the single Mikuni 34mm kit for 7 years, with a separate choke lever. Would never go back to the amal's. Easy start, smooth through out every range. I have several Kawasaki Triples from the 70's all have mikuni's, run Great!!!! do yourself a favor, you will be so pleased.
 
acotrel said:
A friend of mine had a Super Rocket BSA - said it was the worst vibrating bike he had ever ridden. They were however, very quick. Had the edge on the 650 Bonneville.
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Quick?

With an honest 28-30 RWHP when in perfect condition they are anything but quick. Vibes on my SR aren't bad though. Not Commando smooth but quite acceptable at 65 mph.

The testers of the day felt the need to greatly exaggerate performance levels to help with sales.
You can see some of the same in the Commando tests, but the Commando comes much closer to fulfilling expectations created by the testers.

Glen
 
A friend of mine had a Super Rocket BSA - said it was the worst vibrating bike he had ever ridden.
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I always thought a 441 victor was the single worst vibrator
 
Here's a list of the above mentioned book from Amazon,com....must be pretty good for that kinda scratch (in USD, btw)! It's about 40x less from Amazon.ca, Eh!




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1up3down said:
A friend of mine had a Super Rocket BSA - said it was the worst vibrating bike he had ever ridden.
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I always thought a 441 victor was the single worst vibrator
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I got mine properly balanced, very smooth up to an indicated 50 MPH.

Now the Panther 650, that's a paint mixer!
 
Am I the only guy that has had a chunk of the slide of an Amal break off 100 miles from home? Never found it. I can only assume that it went through the engine. It would only run at idle or wide open. It was an interesting ride home. I now have single Mikuni. If the slide broke on a single carb bike, you would be dead in the water. No limping home.
 
RoadScholar said:
I got mine properly balanced, very smooth up to an indicated 50 MPH.

Now the Panther 650, that's a paint mixer!
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I met a Panther owner at the Winthrop Wa. Vintage bike gathering last year.
When asked about performance he said
"It doesn't really accelerate. I like to think of it as a building of momentum"

Glen
 
worntorn said:
I met a Panther owner at the Winthrop Wa. Vintage bike gathering last year.
When asked about performance he said
"It doesn't really accelerate. I like to think of it as a building of momentum"

After owning a BMW S1000RR I now feel the same way about my 850 Commando. What a great quote.
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Mike Gaylord sleeved my 932 Amals in 1998 on my combat. They have been working great for the last 35,000 miles. I did try a single Mikuni 34mm and got the correct jetting from Ken Armann. I didn't care for the loping idle, sounded like a sportster. Subjective yes, but it's all about perception on this subject. Thirty years ago I did a roll on with one of the other club members (Tom Borman) from 60mph out on the Pacific Coast Highway near Big Sur. He was on a '74 850MkII with single Mikuni, I was on a '73 750 MkV with stock Amals. Mine definitely pulled away.
 
illf8ed said:
Mike Gaylord sleeved my 932 Amals in 1998 on my combat. They have been working great for the last 35,000 miles. I did try a single Mikuni 34mm and got the correct jetting from Ken Armann. I didn't care for the loping idle, sounded like a sportster. Subjective yes, but it's all about perception on this subject. Thirty years ago I did a roll on with one of the other club members (Tom Borman) from 60mph out on the Pacific Coast Highway near Big Sur. He was on a '74 850MkII with single Mikuni, I was on a '73 750 MkV with stock Amals. Mine definitely pulled away.
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How can you get the correct jetting from somebody else when every bike is different ? You might get a starting point but the rest is up to you. It only takes the slightest bit too rich to make a motor sluggish. So comparisons of single and dual carb setups are not straight forward. It is critical to get the needle jet and needle right. If you had a single Mikuni with the needle one notch to high, or a slightly worn needle jet, it would be slower than dual carbs with the needles right and vice versa. In every case, tuning a bike is a rigorous process and the results can be temperature dependent. If you get one bike right on a very cold day, it will probably be slower on a hot day. If the other bike was tuned on a hot day, it will be faster.
 
illf8ed said:
Mike Gaylord sleeved my 932 Amals in 1998 on my combat. They have been working great for the last 35,000 miles. I did try a single Mikuni 34mm and got the correct jetting from Ken Armann. I didn't care for the loping idle, sounded like a sportster. Subjective yes, but it's all about perception on this subject. Thirty years ago I did a roll on with one of the other club members (Tom Borman) from 60mph out on the Pacific Coast Highway near Big Sur. He was on a '74 850MkII with single Mikuni, I was on a '73 750 MkV with stock Amals. Mine definitely pulled away.
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Loping idle? Not jetted correctly. Pulled away from him? Wouldn't be the gearing difference would it?
 
acotrel said:
How can you get the correct jetting from somebody else when every bike is different ? You might get a starting point but the rest is up to you. It only takes the slightest bit too rich to make a motor sluggish. So comparisons of single and dual carb setups are not straight forward. It is critical to get the needle jet and needle right. If you had a single Mikuni with the needle one notch to high, or a slightly worn needle jet, it would be slower than dual carbs with the needles right and vice versa. In every case, tuning a bike is a rigorous process and the results can be temperature dependent. If you get one bike right on a very cold day, it will probably be slower on a hot day. If the other bike was tuned on a hot day, it will be faster.
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I totally agree
 
XTINCT said:
Am I the only guy that has had a chunk of the slide of an Amal break off 100 miles from home? Never found it. I can only assume that it went through the engine. It would only run at idle or wide open. It was an interesting ride home. I now have single Mikuni. If the slide broke on a single carb bike, you would be dead in the water. No limping home.
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However, I have never heard of anyone breaking a slide on their Mikuni. As mentioned earlier, the rubber mount probably has a lot to do with that.

Nathan
 
I did back to back new 34 Mulkuni vs new dual Amal 932's I'd indexed to match on Ms Peel - believing general factory and forum wisdoms - to find Amals better up to 4000 rpm then 34 mm pulled better and to higher top end, in Ms Peel's case. I could not play with then current sports bikes on 2 Amals so reverted to Japaneese but like Amals better off road and for looks and normal legalist use of bone stock Trixie.

I've spare Mukuni kit that came on Trixie Combat so offer to lend it to someone willing to see for themselves to report the power character on their particular steed. Will sell at fair price if as pleased as I was performance wise, not looks or air filter hassle. Trixie runs Peel's rejected Amals for one kick starts, slow lugging idle on hi throttle up steeps and sustains 115 keeping up with sane moderns on joy rides. Amals have hit 120 indicated a few time into redzone but they have the BSA flow slot mod or would not be able to sustain over the ton for long. Differences only noticed on WOT snaps and long WOT.
 
Fullauto said:
Loping idle? Not jetted correctly. Pulled away from him? Wouldn't be the gearing difference would it?
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1. Most don’t get Mikuni jetting correct. I trust Ken Armman’s experience and recommendation.
2. Gearing on both my 750 and Tom’s 850 was the same. Frankly the discussion of Mikuni versus Amal has been around for more than 30 years. Same as always it’s a matter of opinion.
 
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