peashooters

Another question! I have a mk 3 850 and have changed the carbs to a single amal mk2 and have andover peashooters on it. The bike had exhaust pipes with no balance pipe and black cap silencers on it with the standard 2 carb set up when i bought it but it was never right as the carbs were worn and the wiring suspect.
The bike is much improved with all the work done, but having not ridden another mk3, don't know whether i would benefit from the balance pipe exhausts?
The bike was running hot when I collected it so the pipes look a bit blue and brown, and I often get asked 'is your bike overheating?' but the only problem I have is a bit of sooting up of the plugs after the Christmas lay up, but that cleared up on a recent run.
I am minded to run it through the summer and see how I get on, but if I change the pipes, do I go for the balanced type?

The balanced pipes give you a bit more umph at mid-range but not a lot, you lose some of the sound and you gain braking welds at the joints.

mcmarvelous said:

The bike had exhaust pipes with no balance pipe and black cap silencers on it with the standard 2 carb set up when i bought it but it was never right as the carbs were worn and the wiring suspect.

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Black caps are supposed to need the balanced system otherwise there's a loss of power.

mcmarvelous said:

The bike is much improved with all the work done, but having not ridden another mk3, don't know whether i would benefit from the balance pipe exhausts?

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You'd probably not be able to notice any difference between the balanced and unbalanced pipes with peashooters?

Forum member "ludwig" experimented by fitting a valve in the balance pipe that could be opened and closed as he was riding, and he said he could detect no difference between the valve when open or closed.

I've used both types on my MkIII with peashooters and I didn't notice any difference between them, although the balanced pipe sytem may be slightly quieter?

I believe the main reason for the balance pipe was for sound reduction, with the added benefit of lower back pressure, possibly resulting in more power.

I can tell from personal experience that the separate pipes ARE louder, but the difference in power is undetectable to me.

After cracking two exhaust pipes in 800 miles, I went to 750-style pipes. no issues in a further 3000 miles.

Usually if the muffler is restrictive a balance pipe will give a bit more power, they are nearly always quieter.

that settles it for me. I am happy with the noise and I will concentrate on getting the carb set just right. I believe the bike may be down slightly on power compared to 2 amals, but I never really thrash the bike anyway and the 'old' set up was worn out so I don't know the difference!

I would think that the single Mikuni might just give more power in the area where you would actually use it unless you race.
You can't say this for all combinations but in most cases a single carb gives a bit more mid range torque. The average person spends little time in the 90-110 mph range, maybe I should say adult, I just recalled my behavior when I was a kid.
One thing about modern carbs is that they were designed with 30 years of knowledge behind them. That's about the period I'd seperate the Amal design from the Mikuni by.
When you take those Mikunis apart the circuits are much more sophisticated, and the slides are designed for minimal wear. By this token they would not be as easy to fix by the side of the road, but with clean fuel they don't break very often.
If I don't like the Kehin copies I'm trying on my Norton I might just try one of the various Mikunis I have around. Let's see, I have 8 spare Kehins, 4 Amals, 4 Mikunis, and two Bings. Maybe I ought to quit messing with carbs.

You are quite right as I sold a modern triumph Triple and that had all the performanc you could shake a stick at but the Norton is happier around the speeds I usually end up doing ,approx50-65 round the lanes where I live . i say approx as the speedo is not playing at the moment.
I used an Amal mk2 carb, which gave me a load of heartburn, and only did this after being convinced by a specialist that the mikuni's available in England were not right for my bike. I actually bought the amal kit from another specialist in England and am fairly happy now it is sorted.
That said, since I have had the Norton, I have found that if you ask 5 people advice on what to fit, you get 6 answers! This site has been a help though as at least it is people who have and do use their bikes with the opinions.
Anyone know how much the new Norton will be? I did e-mail them last week and from the blurb I have read, reckon that the bike will be in Harley 1450 territory for price.
If it were around the same money as the sport classic Ducati bikes I think it has a chance as I can't see them competing with Hinckley triumphs, and the new owner said as much when he was reported as saying words like 'niche product' and 'not after Triumph's market' in MCN.

As an ex mechanic I'd have to agree with you about opinions. Folks tend to find a combination that works for them. The guy who told you to use an Amal probably got good results and knew how to set one up.
If you are doing a job every day you tend to go for the combination that you know works, you don't want an unhappy customer coming back.
INMHO the Chinese copy Mikunis are not up to the old Japanese ones. I have had to do repairs to them like slide guides, which I never had to do with original ones.
I have not seen the new Amals so I'll leave that up to those who have. From what I've heard it is a shame they did not improve the design a bit.

You're right Cookie, the new amal i got, spanish made, never worked out of the box. Got a new float, bowl etc from the supplier (lots of help from them also) but in the end got the club guru to look over it and the choke circuit wasn't working and the casting of the carb was causing the flooding which i experienced on 'bolting it on'
The advice on the Mikuni's was in a similar vein, ''not the right stuff in England''.
You live and learn. Were I doing it again, I would have used a Amal mk 1 (I had 2 of them already, easy to work with) and reconditioned them.

From what I've heard reconditioning an Amal might just make an excellent unit for an old bike. The problems I always had were slide and body wear, and it would seem that could be fixed with better materials.
The other thing was the pilot circuit plugging and I've seen someone's tequiniqe of drilling that for a plug that would make easy cleaning.
You can also upgrade the tickler and the float valve.
If I don't like the Kehins this year that may be the way to go. They also have that nice vintage appropriate look, I especially like them with velocity stacks. Reminds me of when I was 16 and trying to figure out if I got more power with my new velocity stacks. (I didn't, same ET.)

Cookie said:

You can also upgrade the tickler and the float valve.

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Is this something to be done with a brand new pair of Amals? I got a new set for a Triumph I'm working on. never touched an Amal before as my Norton has a single 36mm Mikuni.

Our mate mcmarvelous is better equipped to answer that as he has used the new Amals.
It sounds to me that you should at least strip them and inspect them before use.
I would not resleeve or be drilling holes in new carbies, plenty of time to do that after you wear them out.

Cookie said:

Our mate mcmarvelous is better equipped to answer that as he has used the new Amals.
It sounds to me that you should at least strip them and inspect them before use.
I would not resleeve or be drilling holes in new carbies, plenty of time to do that after you wear them out.

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I did think about sending them to Lund to get new slides put in before I even really use them.

There are plenty of worn out Amals that you could resleeve before you bother with new ones.

Carbs

I had my original 932/19 and 932/20 carbs sleeved by Mike Gaylord in 1998 during the restoration of my '72 combat roadster. Now after 11 years and over 20,000 miles the slides and bodies show almost no wear. I prefer Amals mostly because they fit so well. The stock air cleaner with K&N air filter is also very efficient and large. I have no doubt that a single Mikuni will idle better, but anywhere else the Amals operate very well provided they get new jet needles and needle jets every other year (about $40). Although I don't typically run over 100mph, I do rev the bike in lower gears just for the rush and sound of a combat. Twin carbs are all part of the effect.

David

Hi COCo, the amal units on the commando from new (mk 1 concentrics If i remember correctly) need tickling to partially flood the carb when you start the beast. the mark 2 carb has a more modern choke lever on the carb so no tickler. Now the bike is up and running I don't really see much of a difference. Whatever I do it will be very slow copmpared to my hinckley triple, so i go for noise and reliability!
If it is a T140 you have, they had Mk2's I think (certainly the Tiger single carb one did toward the end of production).

Coco said:

Cookie said:

You can also upgrade the tickler and the float valve.

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Is this something to be done with a brand new pair of Amals? I got a new set for a Triumph I'm working on. never touched an Amal before as my Norton has a single 36mm Mikuni.

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New Mk1 Amals should already have the extended tickler buttons and viton tipped float needles, so nothing needs to be done.

mcmarvelous said:

If it is a T140 you have, they had Mk2's I think

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Amal Mk2s were introduced on the Bonneville T140E models in early 1978 (the V models kept their Mk1s until the end of V model production later on that year).

mcmarvelous said:

(certainly the Tiger single carb one did toward the end of production).

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As far as I'm aware, all Tiger TR7RV & T models had a 30mm Mk1 Amal up to the end of Tiger production? Well, thats what the last model Tiger parts book lists (Amal 930/94).
The TR65 & TR65T also had a single Mk1 Amal. Some late model Bonnevilles did have Bings!
And the Harris models had the Amal 2900 "1-1/2" carbs.

Bings on Bonnies? Didn't that cause tissue rejection? I had no idea they were ever fitted with more modern carbs, I guess I was out of bikes at the time.

I was referring to what I would do to refit an old Amal. Actually what I'm thinking of doing to one of my sets if I don't like the Kehins. On a new carb I would not mess with it at all, other than checking to see if it was right. The shoddy assembly I'm seeing on some reproduction bike parts is quite disappointing.

I'm glad to hear another guy vote that his re sleeved Amals are not wearing much. On the other hand I'm just back from the coffee shop with my Mikuni equipped Chang. Those suckers start instantly, warm up quickly, and pull sweetly through the gears. My Honda would be still warming up with the stock Kehins. I've not used a Mikuni on a Norton but if they work like they did on my snowmobiles and my Chang I bet they can be pretty sweet.