Advice on Amal settings for ‘74 850 please

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kn0ck4times said:
Ok I’m going to try 260 main and 19 pilot , 2-ID needles, flat topped-spray tubes and 3.0 slides first and see what happens. Just wanting to get these acceptable for now. Will probably put a makuni on when the budget allows.
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You already have Premier carbs. You got good carbs there! There’s no reason why you shouldn’t be able to get these to run WAY better than ‘acceptable for now’ …
 
One option is Sell them. To someone who has a 750 and get the new aluminum bodied Amal Premiers.
you will save 1.5 lbs between the two. Plus you get what you need for all your parts that you need to replace to sort it out. 691-R932/29/PREM 691-L932/30/PREM.
Job done.
 
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Your report of hesitation at throttle roll on indicates a dip in richness transitioning from pilot to needle jets. I've just gone through a bit of this tweaking, 850, hamcan k&n filter, non balanced headers and peashooters. I have premiers with the correct 850 setup as Greg Marsh listed earlier.
I solved some issues with balancing the carbs using a Morgan CarbTune Pro (about $80 from UK). Some popping out the back, indicating lean condition, could be dialed out by richening the air screws (turn them CW to richen ). But the hesistation lingered until I raised the needles up by putting the clip on lowest needle notch. Bike feels and sounds completely better. Plugs still not getting sooty. If I were you, before splashing out for lots of new jetting etc, give it a try to see if you can get closer to what your bike wants.
 
"He already has Premier carbs, so definitely worth trying to sort them out !"

I guess so.

Re the setup, can't imagine who would have thought 220s were suitable main jets for an 850 Commando. Heck, mine used 240s when living in Mexico City at 7600 feet. 220s would probably have been good at 12000! :)
 
MexicoMike said:
Re the setup, can't imagine who would have thought 220s were suitable main jets for an 850 Commando.
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It seems likely somebody bolted on a pair of standard specification 932 (/300 & /301) Premiers without changing anything.

Premier LH 32mm 4 Stroke MK I Carburettor - The AMAL Carburetter Company

<p>This carburettor is built to a standard specification which provides approximate settings for this bore size and carburettor type. Ideal for anyone who wants to tune their machine themselves.</p> <p>Comes fitted as standard with:</p> <p>3 Cutaway Sli
amalcarb.co.uk amalcarb.co.uk

Premier RH 32mm 4 Stroke MK I Carburettor - The AMAL Carburetter Company

<p>This carburettor is built to a standard specification which provides approximate settings for this bore size and carburettor type. Ideal for anyone who wants to tune their machine themselves.</p> <p>Comes fitted as standard with:</p> <p>3 Cutaway Sli
amalcarb.co.uk amalcarb.co.uk

"Part Number: 932/300PREM
Part Number: 932/301PREM

This carburettor is built to a standard specification which provides approximate settings for this bore size and carburettor type. Ideal for anyone who wants to tune their machine themselves.

Comes fitted as standard with:
3 Cutaway Slide Hard Anodised
220 Main Jet
106 Needle jet
Premier Pilot Jet"
 
kn0ck4times said:
So in your opinion Les would you just start with the main jets at 260 and leave everything else as is and give it a try or completely overhaul?? Starts getting expensive when eventually I will probably put a makuni on it.
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If you think you want a single Mikuni; then, in my opinion, do that now. The pilot jets and slides are expensive and the carbs you have would work well for someone with a Combat or a 73 750 with a RH5 or RH6 head. AMAL still specifies #17 pilot jets for 750s although I use #19 in all Commandos. 750 Commandos also use 3 slides. You should be able to sell the set you have for close to enough to get a single Mikuni kit or you may be able to swap with someone.
 
marshg246 said:
If you think you want a single Mikuni; then, in my opinion, do that now. The pilot jets and slides are expensive and the carbs you have would work well for someone with a Combat or a 73 750 with a RH5 or RH6 head. AMAL still specifies #17 pilot jets for 750s although I use #19 in all Commandos. 750 Commandos also use 3 slides. You should be able to sell the set you have for close to enough to get a single Mikuni kit or you may be able to swap with someone.
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Looking to buy the mikuni kit from cnw eventually, don’t like loosing the ham can . I want simplicity and reliability. I have issues making choices and will probably end up with both.
 
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OK what do you have.... and what do you need to get your Amals to the 850 spec....
#1 pilot jet #19 after vat 17.15 X2 =34.30
#2 Main jets: X2 @ 4.70 with vat pounds - British =9.4 whats the pound symbol???
#3 Slides X2 £41.75 with VAT = 83.50
#4 Needles X2 10.93 VAT each = 21.86
all taken from http://amalcarb.co.uk/
Spray tube debatable as per ludwigs findings. But I won't go there. that is another topic.

Now:
you go mikuni then price for 2 in one intake manifold? Unknown? then carb unknown...then the ham can plate.
etc etc
YMMV
Cheers,Tom
 
bchessell2 said:
later 850 carbs had 3 1/2 slides with split spray tubes with the longer needles to stop the mid range hesitation.
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All 850 carbs.

The stepped spray tubes and 4-ID needles allowed the 850 models to comply with a US rolling acceleration test when the throttle had to be snapped open in top gear at low speed with mutes fitted.

(Edited)
A new acceleration test was introduced for USA and from memory the test was 40 mph snap open throttle in top gear, this was fine without the mutes fitted, but with the mutes ( small disk fitted to the end of the exhaust silencer), this caused a[...??????...] the muted condition, ..............................the final cure was to install a cut away spray tube, this allowed a much smaller main jet to be used, this in turn stopped the eight stroking when trying to pass the USA acceleration test, I think 40 to 60 mph in a certain time.

It is not difficult to see how this worked, FOR THE MUTED CONDITION

Most times with the mutes fitted we would snap at the 1/4 mile point at 30 and 40 mph and be doing the same speed, 30 or 40 mph at the timing lights, after 1/4 mile, of course, you could feather the throttle back and judicially pick up speed and improve, but the idea was that a person when accelerating passed a long vehicle could not be expected to intervene and should expect a solid reliable acceleration.

You may not be aware that AMAL did not set up the Carburettors for the trade, BSA, TRIUMPH, NORTON but development worked closely with Amal, and the responsibility for final sign off and payment was down to the Test and Development department of each of the firms, as Deputy group test rider under Bob Mann's we carried such responsibility........

One final thing that would vindicate the modification was the fact that we had over 150 bikes held up and not allowed in California test Authority, and after the modification, they and all subsequent Nortons passed straight in.
I am not sure if Alan Lines? of Amal is still alive but he would no doubt give ....chapter and verse on how and why the cutaway spray tube was beneficial to the MUTED CONDITION.

Regards
Bob Rowley
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CanukNortonNut said:
OK what do you have.... and what do you need to get your Amals to the 850 spec....
#1 pilot jet #19 after vat 17.15 X2 =34.30
#2 Main jets: X2 @ 4.70 with vat pounds - British =9.4 whats the pound symbol???
#3 Slides X2 £41.75 with VAT = 83.50
#4 Needles X2 10.93 VAT each = 21.86
all taken from http://amalcarb.co.uk/
Spray tube debatable as per ludwigs findings. But I won't go there. that is another topic.

Now:
you go mikuni then price for 2 in one intake manifold? Unknown? then carb unknown...then the ham can plate.
etc etc
YMMV
Cheers,Tom
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The mikuni I would purchase is probably the CNW kit, which seems to have everything needed except maybe new fuel taps for $450 USD. Amal restoration seems like a couple hundred. I’ll have to think on it, meanwhile new fork boots and ignition rubber will be here this week.
 
kn0ck4times said:
The mikuni I would purchase is probably the CNW kit, which seems to have everything needed except maybe new fuel taps for $450 USD. Amal restoration seems like a couple hundred. I’ll have to think on it, meanwhile new fork boots and ignition rubber will be here this week.
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I didn't account for the fuel lines. But that was the etc. etc. I included. You be the judge. Its your money.

Cheers,
Tom
 
CanukNortonNut said:
I never had a muted exhaust pea shooter. Too far away from Californication.

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My '74 850 came to me as a HiRider with muted peashooters. Pretty sure this bike was originally a Canadian import (it had the Canadian lighting switch and circuitry) and was registered in Alberta by some previous owner.
The muted shooters were pretty chirpy, but that turned out to be from internals becoming separated and rattling. Now has open peashooter and things are good.
 
your the first man.
how many other Canadians ???. please respond.
show us how many went to the mutes?
 
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"Normally I just change all fuel and electronic changes from my phone. "

perhaps one of these might help .

Advice on Amal settings for ‘74 850 please


Many similarities in opperating them , anyway .
 
" My '74 850 came to me as a HiRider "

Was a blue L & R hi pipe 850 in Auckland , centuries ago .

Ran the Ace Bars , on mine . inverted (up'n'back ) ditto .
With f Glass H rider tank , Flat track-ish ; similar to the P-11 .

So it has its followers , at least youd fit a bit of gas in the steel one !
 
CanukNortonNut said:
I didn't account for the fuel lines. But that was the etc. etc. I included. You be the judge. Its your money.

Cheers,
Tom
Click to expand...

Matt Spencer said:
"Normally I just change all fuel and electronic changes from my phone. "

perhaps one of these might help .

Advice on Amal settings for ‘74 850 please


Many similarities in opperating them , anyway .
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best to disconnect all together. no problems, are we now. yer phone can be put in a faraday pack or bag So Google doesnt know where your going.
Matt Spencer said:
"Normally I just change all fuel and electronic changes from my phone. "

perhaps one of these might help .

Advice on Amal settings for ‘74 850 please


Many similarities in opperating them , anyway .
Click to expand...
say what
 
CanukNortonNut said:
your the first man.
how many other Canadians ???. please respond.
show us how many went to the mutes?
Click to expand...

The 850 Mk2 06-4609 peashooters had restricted (1 1/8") outlets instead of the previous 06-1978 (1 3/8") outlet peashooters where mutes were fixed with screws "as required" by some US states.

www.accessnorton.com

Original mufflers? -How to tell?

Guys, I was recently at my local Gateway Nortons Owners club and one of the guys mentioned to me that it looked like I had the original mufflers on my commando. He said that original ones didn't have a straight edge at the tips. As you can see on mine if you zoom in, at the end of the muffler...
www.accessnorton.com www.accessnorton.com
 
L.A.B. said:
The 850 Mk2 06-4609 peashooters had restricted (1 1/8") outlets instead of the previous 06-1978 (1 3/8") outlet peashooters where mutes were fixed with screws "as required" by some US states.

www.accessnorton.com

Original mufflers? -How to tell?

Guys, I was recently at my local Gateway Nortons Owners club and one of the guys mentioned to me that it looked like I had the original mufflers on my commando. He said that original ones didn't have a straight edge at the tips. As you can see on mine if you zoom in, at the end of the muffler...
www.accessnorton.com www.accessnorton.com
Click to expand...
Mine were welded in. Did have plans to drill them out, even bought a super fat multi-step drill bit for the job. But delayed the operation long enough that the universe coughed up a nice set of open peashooters on a local craigslist ad. :)
 
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