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Monobloc Carbs

lomaxjohn

Active Forum Website User
Non-VOC Member
With reference to the Neville Higgins article March 2008
I am asking about carburettor jetting for 1 3/16 Monobloc carbs
Are the jet sizes quoted page 172 Know Thy Breast still applicable?
Engine fitted with Mark II cams and Lightning exhaust pipes (not worked out how to silence them yet)
Don't wish to burn the pistons out on start up
Regards
John
 

john998

Well Known and Active Forum Website User
VOC Member
1 3/16 monoblocs

Hello,
Yes the know thy beast numbers are a good start, my Rapide with a similar set up runs fine on them.
Worst aspect is that the adjustments have minimal effect, and fuel consumption is poor. Mk2 concentric are much better. John.
 

lomaxjohn

Active Forum Website User
Non-VOC Member
Monoblocs

Thanks for your reply
I agree with you over using more modern carbs but I am trying to maintain the 60's look and I have just refurbished the carbs. What a job on my little lathe
Regards
John
 

john998

Well Known and Active Forum Website User
VOC Member
Monoblocs

Hello John, yes resleeving is a difficult job you have to make the holding mandrels as you go along. I bored the body on mine and sleeved the slide. Monoblocs wear very quickly, 20k and they are slack. A big improvement after sleeving, but sadly a pretty primitive device.
On my outfit 35mpg is about the best to be expected.
The consumption on the
solo with the Mk2s fitted is around 55mpg, an improvement of at least 5mpg compered to the monoblocs. Also you can set up the tick over with relative ease, and it starts with less effort.
 

lomaxjohn

Active Forum Website User
Non-VOC Member
Monobloc's

Hi John

For the mileage I plan on doing petrol consumption is a secondary issue and I just love my pair of Monobloc's. I manage to source a 689 carb from America so I have a matched pair. My friend swears by Mikuni carbs on his twin. Technically I have to agree the modern carbs far better on all aspects and they would be a better fit on my Norvin but at the moment its Monobloc's for me

Regards
John
 
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