What Monobloc's carburetors do I have?

Monaro

Joined
Apr 14, 2012
Messages
19
When I got my 1966 N15CS in various pieces, it came set up with concentric carburetors, but there were a pair of monobloc's. As I would like to return the bike to standard I started to do some research on them, trouble is I am I not sure what I have. In 1 of my books it states that the carbies on a G15 should be R/H 389/88, L/H 389/87. Mine are 389/211 (Chopped) and 389/210. I looked at the numbers dozen of times, polished them, looked under light and that's the numbers. It should have a 1 1/8 bore, measured them (with digital verniers) comes up with 1.434" is that the same?
any help would be great,
Cheers,
Monaro. :( :(
 
Thanks mate, From that list I do have the right ones. No I measured the bore (where slide goes down)) didn't know that it meant the throat size (that's what we refer to it over here.)
Thanks for your help.
Monaro.
 
Norton changed to Concentrics part way through the '66 model year so it is possible that either carb would be correct. You will have to research the specific vin for the change over point to be sure.
 
triumph2 said:
Norton changed to Concentrics part way through the '66 model year so it is possible that either carb would be correct. You will have to research the specific vin for the change over point to be sure.
Click to expand...

66 or 67? My 67 came with monoblocs- since replaced by concentrics- and a magneto...
 
wjrich said:
triumph2 said:
Norton changed to Concentrics part way through the '66 model year so it is possible that either carb would be correct. You will have to research the specific vin for the change over point to be sure.
Click to expand...

66 or 67? My 67 came with monoblocs- since replaced by concentrics- and a magneto...
Click to expand...
It was 67! after serial number 121000 I believe. At the same time as the changeover to coil ignition took place.
 
wjrich said:
triumph2 said:
Norton changed to Concentrics part way through the '66 model year so it is possible that either carb would be correct. You will have to research the specific vin for the change over point to be sure.
Click to expand...

66 or 67? My 67 came with monoblocs- since replaced by concentrics- and a magneto...
Click to expand...

It is possible your 67 was titled as such, but was actually built in 66. The NOC records can tell you the dispatch date of your machine. See http://www.nortonownersclub.org/records ... ory-record

As an example, my Atlas was bought new in Apr 63 and titled as 63. NOC records show it left the factory May 62. Why it took nearly a year to hit a showroom floor is a mystery to me, and I do not know if such a delay is typical.

The NOC dating records will not tell you much more about your machine, except for which distributor took delivery and paint colors, and IIRC, you will get gearbox number as well. If you do the dating research, do not expect the document to tell you which carbs were fitted.

Of course, the NOC VIN vs year of production will give you a ballpark idea when your machine was built.


Slick
 
texasSlick said:
wjrich said:
triumph2 said:
Norton changed to Concentrics part way through the '66 model year so it is possible that either carb would be correct. You will have to research the specific vin for the change over point to be sure.
Click to expand...

66 or 67? My 67 came with monoblocs- since replaced by concentrics- and a magneto...
Click to expand...

It is possible your 67 was titled as such, but was actually built in 66. The NOC records can tell you the dispatch date of your machine. See http://www.nortonownersclub.org/records ... ory-record

As an example, my Atlas was bought new in Apr 63 and titled as 63. NOC records show it left the factory May 62. Why it took nearly a year to hit a showroom floor is a mystery to me, and I do not know if such a delay is typical.

The NOC dating records will not tell you much more about your machine, except for which distributor took delivery and paint colors, and IIRC, you will get gearbox number as well. If you do the dating research, do not expect the document to tell you which carbs were fitted.

Of course, the NOC VIN vs year of production will give you a ballpark idea when your machine was built.


Slick
Click to expand...
A few years back, my curiosity got the best of me and I had NOC do the search. They couldn't tell me much more than that it was shipped to Berliner in March of 67. I guess it's possible it was built in 66 and sat in inventory somewhere, but I do recall hearing somewhere- don't recall where- that the early 67s were configured this way. In a way it's kind of like asking your wife how many people she slept with before you got married- after almost 50 years it really doesn't make a whole heck of a lot of difference.
 
I would say dispatch to Berliner in March 67 is fairly good proof the machine was built in early 67. The first rule in business is "get the product out the door", and the second rule is "send the invoice". Thus, it would be doubtful the machine would sit in a warehouse for months. OTOH, mine was dispatched to Berliner, and may have gotten "lost" in Berliner's warehouse.

Where does the VIN fall in the allotment for the 1967 year? How does the VIN relate to triumph2's 121000 number?
IIRC, 1967 was the year concentrics appeared on the Atlas, as triump2 attests, but maybe it was later in the year ... I dunno.

It is hard to imagine a PO replaced concentrics with monoblocs. If you still have the monoblocs, what are the numbers on them and how do they relate to the application guides posted above?

Your Atlas may be an anamoly as mine is .... there are a half dozen points I can mention why mine seems to be a "one off". It makes me wonder how many of these "one offs" may be out there?

I was disappointed also at the little bit of info on the NOS records, and emailed the records guy with a query whether there might be more records available .... never got an answer.

Hope you shed more light on this.

Slick
 
texasSlick said:
Where does the VIN fall in the allotment for the 1967 year? How does the VIN relate to triumph2's 121000 number?
IIRC, 1967 was the year concentrics appeared on the Atlas, as triump2 attests, but maybe it was later in the year ... I dunno.
Slick
Click to expand...
It was partway through the model year, not at the beginning
 
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