Back to my old Amal carbs

hhh if only you asked me that a few days ago when I had the tank off lol, at the moment I am going out to ride it, but I got to get a new fuel tap as the reserve tap is leaking slightly so when I get that I will pull the tank off, but all I did is use the bottom Commando head cut where the 3 Allen head bolts that mount on the top of the head and a 5mm plate of steel that i,s shaped for the 3 mounting holes on the frame, it all depends how and where your motor sits in the frame with the bottom engine mounts once you have them mounted you just make the top mount to suite, I made all my engine mounts cut out of 5mm plate steel.
It's very important that the head stay is strong.

Thanks ashman, no hurry on this end. I appreciate it. I was mainly wondering about thickness and how much contact between it and the plate on the engine. I know the early Commando ones liked to break, so I want to make sure it's stout enough for the job and yours has lasted 40+ years. I'm using Converta plates at the Commando angle. For some odd reason they didn't drill the hole for the center of the primary standoff.

hhh said:

Thanks ashman, no hurry on this end. I appreciate it. I was mainly wondering about thickness and how much contact between it and the plate on the engine. I know the early Commando ones liked to break, so I want to make sure it's stout enough for the job and yours has lasted 40+ years. I'm using Converta plates at the Commando angle. For some odd reason they didn't drill the hole for the center of the primary standoff.

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The head steady plate needs to be a minimum of at least 5 mm thick steel imo
When I did it I used 6mm thick with zero tolerance in the bolt holes they were drilled to suit
Don't forget the head steady forms part of the frame on a featherbed

baz said:

The head steady plate needs to be a minimum of at least 5 mm thick steel imo
When I did it I used 6mm thick with zero tolerance in the bolt holes they were drilled to suit
Don't forget the head steady forms part of the frame on a featherbed

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I tend to believe that the hole clearance is irrelevant as long as they're not too big so as to impair clamping force. It's the clamping force that creates the bond between mount and engine. I agree it's a necessary part of the Featherbed structure.

hhh said:

I tend to believe that the hole clearance is irrelevant as long as they're not too big so as to impair clamping force. It's the clamping force that creates the bond between mount and engine. I agree it's a necessary part of the Featherbed structure.

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Yes I agree the hole size should be irrelevant because the clamping force is doing the work but in practice I have found zero tolerance to be better
A case in point would be the rear engine mount mount studs on a commando racer were reamed oversize for a dead fit
Where the clamping force of the gearbox cradle wasn't enough

Maybe we should start a thread on Commando/Featherbed conversion I be willing to start it and put in what I did but where would we put it in here or in other Norton, what do you think.

That would be great. I think other Norton would be more appropriate because the whole point is "de-Commandoization."

Well maybe does it really matter where as mine is 80% Commando and 20% Featherbed I used as much of my Commando parts as I could the frame, swing arm and tank is the only Featherbed bits with a few other bits thrown in.
Be awhile before I start a new thread as at the moment I will set the idles then take it out again didn't do it yesterday as planned had a bit of a lazy day instead to many beers on Sunday lol and now driving the wife around she's getting back at me for all the times she had dropped me off at the pub or to a mates place for drinks and having to come and get me after a big drink session with the mates or drop other mates home, she was a good taxi driver when we had a belly full.
One mouth into autumn here and we are still getting hot days 32c today can't wait till things start to cool down our winter days are our best time riding without cooking our brains out usually around 18 low 20c days and off course the Norton loves those cooler days.

texasSlick said:

I got 10 x that (85K miles) out of my Amals before sending them out for Sleeving, and the Atlas was still idling well. They were originals on my 1962 build Atlas bought new in 1963, and so titled.

And I ran open bellmouths nearly all those miles.

Slick

Oh, one oddity about my Amals...... neither has a Model/ Configuration number stamped on the mounting flange ...... were they specially selected by Norton? So apples to oranges.

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Yes that is an Atlas. The problem was the introduction of the 32 mm bores when the Combat came out. Same body size but the bore was increased. Less support between the slide and the body. So Apples to Oranges IMHO.

Ok here it is a: I am having a revelation, I am just contemplating....??? Lots of questions to answer.
Commando's vs Featherbed framed bikes.
The question is how does the Isolastics (to keep vibes off the rider, influence the engine and
carbs.

May be Ludwig was right and wants to isolate the carb from the engine with rubber.
no hard fix manifod to carb. Just thinking out loud you know?

Oh Ash...how are the fingers feeling after 4 hours of riding? Ash.... if you don't mind telling at say plus 5k continuous with your great Magie plus plus 850 in a featherbed? U know were just at the pub again... Have another pint!
cheer,

come on, im just waitin....


You me and ..,.

Rubber mounting the carbs is the first thing you should before trying to jet them. If they are not rubber mounted, it is the same as hasving rubber mounts with the carbs touching the frame or a bolt - you can get frothing of the fuel in the carb bowls, which richens the mixture and makes the bike slower.

If I had a Commando with the isolastics, I would still rubber-mount the carbs

CanukNortonNut said:

come on, im just waitin....


You me and ..,.

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Come over and take it for a ride, you be surprised in how smooth it is, my crank has been balanced for the Featherbed, it does have a few spots through the revs it does gets vibes but it always smooths out pretty quick, in 40 years the 850 is pretty good and was my everyday rider as well travelling bike on the open road it will sit very comfortably between 65 and 90 mph all day without any problem with teeth shaking out or things falling off and in these 40 years I have only lost 2 nuts one off the left muffler mount and the top nut off the gear box mount, not bad, to be honest isolastic mounts Commandos seem to loose more things (read the thread on What's fallen off the Commando) even my exhaust clamps stay tight without any locking devices.
My fingers are good as well I have Renthal alloy handle bars they have 7mm thick wall compared to 1.6mm steel bars, I don't wear gloves at all on any of my bikes and have done many 500+ miles trips only stopping for fuel and food and do many all day Sunday rides with mates and my feet stays on the foot pegs.
Just remembered one of my carb manifold did come loose one night 40 mile from home ran the bike home on one cylinder as it was night time didn't relize it was the 2 Allen bolts on the manifold that came loose was a easy fix as the bolts just needed tightening up that was 35 years ago.
Do you think if my Featherbed wasn't a smooth runner or unreliable do you think I would still own it or been my everyday rider from 1982 to 2013 in the Featherbed when I brought a new Triumph Thruxton, but my hotrod 850 Featherbed is still my favourite bike to ride, I am trying to preserve it and is the reason why it's semi retired from everyday riding, the 2016 1200 Thruxton has taken over that duty and now I gone back to Amal carbies it will be ridden quite a lot more than it has been.
When I do start a thread on Commando/Featherbed conversion I will put up more detail in how and what I done to make my Hotrod Norton a great bike to ride, till then you have to wait.
Another thing my fuel tank isn't even bolted down it just sits on top of the Featherbed tank rubbers, if my bike vibrated a lot the tank would vibrate when low on fuel, guess what it doesn't and there is a reason I don't have it bolted or strapped down.

In my workshop manual with the high performance section in the last chapter they have a bit about rubber mounting the carbs on the Commando motor as well a small bit about other carbs, my motor was built to the stage one performance for the road stage two was for racing, I have had this manual since 1977 but I took it a bit more with balancing.

Well just back from another outing on the Norton to get it up to temp to do a few more adjustments, took 4 kicks to get it to fire up not use to the old Amals as well the tuning is out a few spits through the carbs before firing, set the idles up a bit before going out.
After going around the corner from home it did hesitated a little but motor oil still a bit cold but after that was fine going through the gears and sitting on 40mph in top was good, few times a bit lower in speed to dropping it back into 3rd in the slower speed areas cruising around my local area but after about 15 minutes starting to give it a few quick high revs throughout the gears then a run along the highway and gave it a good run in 3rd gear to about 75/80 mph before putting it into 4th ran with out any problems at all, wanted to open it up at top but this afternoon is the start of school holidays and leading up to Easter long weekend next week so a lot on TV about more cops on the road as well speed cameras so backed off.
After the run along the highway I came home and learnt the Norton on the front fence to muck around with the mixtures and idle while it was still running then taking off again for another run along the highway but sat on 65/70mph was running quite well before coming home before the school kids got out from school, the bike was idling good while I opened the side gate then up to the shed were I kept it running and did a few more adjustments while it was hot with the big fan running for the motor.
Got it idling pretty close to where it should be with both mufflers on my hands feeling the same pressure.
But after running its firing up first kick everytime so will see how it goes tomorrow morning for first start.
The first few kick today it gave a slight kick back though the carbies but was more a fuel kick back, as once it's been fired up it starting first kick.
Been so long 12 years now and just got to get use to using Amal carbs again lol.
Sitting over 70mph the bike was pretty smooth running, I am running a 19 tooth front sprocket what came from the factory and same with the rear, the few times I cracked the throttle open it didn't hesitated at all and just opened up pretty quick, I might check the timing but really it's going great so it's pretty close, first kick tomorrow will be the be the big test.

NorLuck said:

My JH lasted 0 miles before needing to be replaced. I'll update you on how long the carbs last

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Proving that romantic folklore on the interwebs is best read for ENTERTAINMENT ONLY, and a person needs to look further to get to solid facts while researching.

ashman said:

.. I don't wear gloves at all on any of my bikes..

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ashman said:

..my fuel tank isn't even bolted down..

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Riding without gloves is not very wise.
In Europe homologated gloves are mandatory.

Over all these years, did you never drop your bike?

Never had gravel rash myself but I have seen the effects on a friends hand - came off on a motorway at 70+ mph - skin and flesh removed on palm and thumb down to the bone with lots of embedded dust tar residues and small stonework. I wasnt a pretty sight.
He used to work as a car mechanic but had to give that up as a direct result.
Ok so the above is an extreme example but even slower speed falls without gloves can be unfortunate to say the least !

As a kid I rode a field bike and fell off on grass at about 15 mph - slid on the grass and had painfull friction burns / abrasions from the grass, I wouldn't want a repeat ... ever ... which is why I always ride with gloves.

Naturally each to their own and all that, I won't judge but will discretely snigger if misfortune strikes

Well 50 years of riding and yes have been down a few time in those 50 years and still have all my fingers I also mostly ride with open face helmets, I have had more cuts on my face from skin cancers cut off, in winter I wear woolly fingerless gloves but we don't suffer extreme colds here in the sub tropics, I like feeling my bike through the handle bars.
Back in 1983 a few months after the conversion to the Featherbed frame my Norton suffered a major fire what saved it from total lost was able to pull the fuel tank off as it wasn't bolted down, ended up min damage from the fire, so could have been a complete lost if I wasn't able to get the tank off.
The times I have been down the road the tank has stayed with the bike.
So no matter what anyone says about not wearing gloves while riding it's my choice not to, same as using a open face helmet, my choice and no one else, it's the risk I take.
Might be a different story if I lived in a cold environment but not wearing gloves don't worry me at all.
By the way the great fire was my own fault velocity stacks, slight fuel leak fron a new fuel tap, back fire from the carbs when starting it,I was on the bike and the motor fired up when hell broke out the flames went up the left arm of my leather jacket as well the top of the bike.