1962 Norton Dominator 88SS carb float setup

Hi,
Can anyone please give some advice .
I have removed the monobloc carbs from my 88ss and fitted Amal Mk 1 concentrics. As the head is a downdraught does anyone know how to set up the float bowl ie dimension above or below the lip of the bowl with the float valve needle fully seated

Many thanks

roadrunnernorton said:

Hi,
Can anyone please give some advice .
I have removed the monobloc carbs from my 88ss and fitted Amal Mk 1 concentric's. As the head is a downdraught does anyone know how to set up the float bowl ie dimension above or below the lip of the bowl with the float valve needle fully seated

Many thanks

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well by doing this you will not again anything your better off using the mono bloc carbs have them refurbished the concentric have completely different jets and settings and their floats are pre set you should have a matched pair of 626R and 626L they have a 25 pilot jet and 180 main jet a 106 needle to set them up you need to remove right-hand cylinder spark plug and start the engine one cylinder only at a time until you have them running on tick over then you get them to tick over on two spark plugs if your running on ethanol you need a change of spark plugs to the new type made for ethanol I now use N9BYC these are the same heat range has the old N5C. But made to use in conjunction with a magneto So if your on electronic ignition you need a different type of spark plug SO Cheak your Heat range out AT www.greensparkplugs.co.uk and check your carburetors out at www.amal.co.uk they still make new carburetors to this day

Hi and thanks for your reply,
I should give a little more detail about the bike.
I removed the mono blocs a good few years ago and sold them on having been told it would run better on concentric MK 1's. I realise now I should have kept them .moving on I have had the head gas flowed and now have twin Mk1 930 fitted with #3 slide 106 needle and 220 main with 25 pilot . Just trying to set it up and being a Downdraught head was wondering what the float should be set to ?
On the electrics side I have converted to 12v with high output alternator with boyer power box and boyer electronic ignition . timing set to 30 degrees BTDC

roadrunnernorton said:

Just trying to set it up and being a Downdraught head was wondering what the float should be set to ?

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The current recommendation from Amal is to set the fuel level rather than the 'float height': http://amalcarb.co.uk/optimising-mark-1 ... uel-levels

With carbs set at an angle I believe the fuel level measurement should be taken at the centre of the float bowl joint, however, I suggest you contact Amal (Burlen) and ask their advice?

http://amalcarb.co.uk/contacts

Hi and thanks
I did contact Amal and have been told that setting the float level with the edge of the bowl and the float needle seated will be ok as there is a large tolerance that should cover the 18degree ? Tilt of the carburettor due to its downdraught position

roadrunnernorton said:

Hi and thanks
I did contact Amal and have been told that setting the float level with the edge of the bowl and the float needle seated will be ok as there is a large tolerance that should cover the 18degree ? Tilt of the carburettor due to its downdraught position

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I've bought an Amal Premier for my 650SS with downdraught head from Burlen. I didn't change anything and it works great.

Fritz

Thanks
That's proof enough !

Hi Fritz
Can you let me know what your carbs set up to
Slide , main and needle jets . I'm interested in making a comparison between the 88ss (500cc) and your 650ss
Thanks

roadrunnernorton said:

Hi Fritz
Can you let me know what your carbs set up to
Slide , main and needle jets . I'm interested in making a comparison between the 88ss (500cc) and your 650ss
Thanks

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Sorry, can't do that right now because I don't want to dismantle it before the winter and I have the bike in my workshop.
All I can tell you at the moment: I've ordered a Premier for the 650SS/1967 http://amalcarb.co.uk/carbspec/carburet ... s/id/6404/

Fritz

bad_friday said:

roadrunnernorton said:

Hi Fritz
Can you let me know what your carbs set up to
Slide , main and needle jets . I'm interested in making a comparison between the 88ss (500cc) and your 650ss
Thanks

Click to expand...

Sorry, can't do that right now because I don't want to dismantle it before the winter and I have the bike in my workshop.
All I can tell you at the moment: I've ordered a Premier for the 650SS/1967 http://amalcarb.co.uk/carbspec/carburet ... s/id/6404/

Fritz

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Thanks Fritz
from the link you gave I see that the 650ss MK I Concentric 600/900 , Needle Jet Size 107 , Throttle Slide - No. 3 Cutaway , Pilot Jet - 25cc and Main Jet - Size 280
My setup is 497 cc 88ss MK I Concentric 300/930 , Neeedle Jet Size 106, Throttle Slide - No. 3 Cutaway, Pilot Jet - 25cc and Main Jet - Size 220

The concentric carbs were developed SIMPLY because the British motor cycle industry demanded Amal supply CHEAPER carbs.
The Monoblock carn is a smooth bore carburetor and flows something like 10 % more air than the equivelent concentric..... so I was told DECADES ago by the Gentleman I spoke with at Amal at the time. For use on the road correctly set up I doubt most of us would notice the difference.
When I built my 1959 (ISH) ES2 I contacted Mr Alan Lines for advice of settings for the concentric carb I intended using but that was many decades ago......Concentrics cost peanuts in those days ex NVT stock!!
What I wanted for our so called classic race Atlas in the 1980s was a pair of left and right hand magnesium alloy monoblocks but such items were even in those days as rare as rocking horse excrement and even more expensive IF you could find any!!....Hanging the heavy std ones on long rubber inlet extensions giving thevrequired length between main jet and valve head required them to be supported via British Layland Mini type metalastic bushes......
I do have a copy of the Amal 1955-61 carb settings list but it only shows the GP and Monoblock settings for 88s. If you want a copy of the relevent Norton page send me your e mail address.

roadrunnernorton said:

…My setup is 497 cc 88ss MK I Concentric 300/930 , Neeedle Jet Size 106, Throttle Slide - No. 3 Cutaway, Pilot Jet - 25cc and Main Jet - Size 220

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Looks ok for me. I'd give this setup a try.
Good luck,

Fritz

Dunstall reckoned that Monos gave the best power ,but was forced to stick with the supplied Concentrics as to switch would have added too much cost to the bikes.