Amals on a 920

mwoo · Aug 6, 2011

Hi all - I have owned my Mk2A 850 for nearly 22 years and converted it to a single Mk2 Amal about 10 years ago - it took quite some time to get the setup correct but overall I was happy with the setup. Four years ago the engine was rebuilt as a 920 and I've subsequently never been over-whelmed by its performance (even after numerous carb alterations) - a few weeks ago I 'bit the bullet' and fitted a new pair of 32mm Amal Mk1s and my God the difference !!!! - it starts first kick and goes like a scalded cat - major "grin-factor". No doubt things will 'go-off' as the Mk1 monkey-metal wears but in the meantime I'm revelling in the new found performance - it's like riding a different bike. I'm sure single carbs may be OK for standard 750s and 850s but I cannot help but think that for a 920 (or bigger) they may not be up to it ( a 36 or 38mm single may be OK but I cannot afford to experiment given the cost of the parts).

Just my observations but it may be of help - - -

Cheers

stockie2 · Aug 6, 2011

Mark that is good to hear the results are positive. I have stuck with Mk1's on my 850 and over a period of time have updated the internals. I have just tried Amal's new hard annodised throttle slides, and these look like really impressive, they should give you Mikuni durability. So maybe you can have your performance & long-life?
I am trying the new floats aswell, because of the ethanol and old plastic worries. Mark, how is the 920 vibe wise compared to the 850?

Cheers Richard

swooshdave · Aug 6, 2011

mwoo said:
Hi all - I have owned my Mk2A 850 for nearly 22 years and converted it to a single Mk2 Amal about 10 years ago - it took quite some time to get the setup correct but overall I was happy with the setup. Four years ago the engine was rebuilt as a 920 and I've subsequently never been over-whelmed by its performance (even after numerous carb alterations) - a few weeks ago I 'bit the bullet' and fitted a new pair of 32mm Amal Mk1s and my God the difference !!!! - it starts first kick and goes like a scalded cat - major "grin-factor". No doubt things will 'go-off' as the Mk1 monkey-metal wears but in the meantime I'm revelling in the new found performance - it's like riding a different bike. I'm sure single carbs may be OK for standard 750s and 850s but I cannot help but think that for a 920 (or bigger) they may not be up to it ( a 36 or 38mm single may be OK but I cannot afford to experiment given the cost of the parts).

Just my observations but it may be of help - - -

Cheers

Twin carbs on a big bike? Hmmm, I'm not surprised it ran better.

Hobot · Aug 6, 2011

I've switched between dual 32'mm and single 34mm to get a new power zone rush, so I suspect the response is better fuel mixture tune than the single vs dual. I did like the bit better response to mid range of the duals than 2 mm bigger single, so that's want I like best on normal operated street C'do. Very happy to hear the excited joy of a happy big block. Is kicking it off an issue?

mwoo · Aug 7, 2011

Hi all - answers to your questions:-

1) Vibes are the same as a 828 - I have a Dave Taylor Head Steady fitted - this has been great as you can 'tune' it to suit your requirements.

2) Kicking-over - quite hard but again after fitting twin 'tickleable' carbs and rechecking (and re-setting) the timing of the Tri-Spark Classic Twin ignition it starts easily compared to using the cold-start device on the single Mk2 Amal. Idon't need to ude the Mk1 Chokes.

HtH

Cheers,

CanukNortonNut · Aug 7, 2011

mwoo
You could get the new anodized slides and put them in your Amal mark 1's before things wear out. This is the way to go if nothing is worn out yet. The dissimilar metals should be a better mix to stop the galling.
My 2 cents
CNN

Amals on a 920

mwoo

stockie2

swooshdave

Hobot

mwoo

CanukNortonNut

Similar threads