How to correctly interpret a parts fiche diagram

[Asterysk]

Would you mind helping me understand Honda's methodology on how they show exploded parts in the fiches, this attachment shows the carb components and it has different part numbers for the needles (items 19 & 20)

I can interpret this diagram in two ways :

A) That needle 19 is used for both the FR carbs (as shown by FR arrow) and needle 20 is for both the RR carbs

or

B) That needle 19 is used for both the LEFT carbs and needle 20 is used for both RIGHT carbs

[another way of asking the question is this:  "is the exploded diagram showing needle 19 for both FRONT carbs or both LEFT carbs"]

There isn't a clue in the part number descriptions

Can you possibly shed some light on how Honda thinks !! many thx

[Brock]

That would seem to indicate different needles..

[PC]

As a spare parts man from early Eighties in Chrysler/Mitsubishi you would come across a part # for left and # for right or front to back
When you went to price list 1 # would supersede to the other # or sometimes they would both supersede to the same new #
They could also list part # 19  #20 in the picture but give them the same # in the list 
When you got new fiches sometimes these changes would be updated
So I am thinking you may need more info  the parts could very well turn out to be the same
Hope this may help   

[Asterysk]

As a spare parts man from early Eighties in Chrysler/Mitsubishi you would come across a part # for left and # for right or front to back
When you went to price list 1 # would supersede to the other # or sometimes they would both supersede to the same new #
They could also list part # 19  #20 in the picture but give them the same # in the list 
When you got new fiches sometimes these changes would be updated
So I am thinking you may need more info  the parts could very well turn out to be the same
Hope this may help   

I hadn't thought of that, will give the parts numbers to the Honda dealer after the holiday and see what they come back with, that would make life very easy if they show them superceded to be the same ! thankyou

[PC]

No worries. Some times there is some trickery stuff in OEM 
Interested to see how you get on

[West Aussie Glen]

I would be fairly confident that it is B.
Item 20 both right hand carbies.
Item 19 both left hand carbies.

[Brock]

In the carb thread, I made a pots that shows a table of parts for the carbs. The needles seem to vary due to country concerned. Some countries use the same needle, others dont... Reason why I dont know.

[Asterysk]

I would be fairly confident that it is B.
Item 20 both right hand carbies.
Item 19 both left hand carbies.

I started by being very confident that it was A and now I'm coming round to the possibility it is B !!

I do tend to look at things a bit differently and having latched onto A initially I'm having a hard time letting go.

I've had a look through most of the other fiches to see if I can find something similar to give a definitive clue but nothing yet.

[Brock]

For info, (if it works)  the country codes are below.

Code    Country
E            England
G            Germany (Full power)
G2            Germany (27PS limited)
F            France
ED            European Direct Sales
DK           General Export (kph)
DM           General Export (mph)
U           Australia
CM          Canada
SA          South Africa
IT          Italy
SW          Switzerland
ND          Northern Europe

[Asterysk]

For info, (if it works)  the country codes are below.

Code    Country
U           Australia

I checked the 'U' country code for ST1100AY and it has the same thing i.e. different needle pairs

needles (19) = 16131-MT3-640
needles (20) = 16151-MT3-640

So looks like Australian spec bikes have different needle pairs also , which hopefully should make it easier to find out if its a LEFT-RIGHT or FRONT-REAR pairing !

[West Aussie Glen]

I would be fairly confident that it is B.
Item 20 both right hand carbies.
Item 19 both left hand carbies.

I started by being very confident that it was A and now I'm coming round to the possibility it is B !!

I do tend to look at things a bit differently and having latched onto A initially I'm having a hard time letting go.

I've had a look through most of the other fiches to see if I can find something similar to give a definitive clue but nothing yet.

I would put money on B

[Asterysk]

I would put money on B

A couple of days ago I would have taken you up on that ! now though I am also coming round to the the probability of B

[ruSTynutz]

[STeveo]

I would be fairly confident that it is B.
Item 20 both right hand carbies.
Item 19 both left hand carbies.

CMS parts show this to be true.
https://images.cmsnl.com/img/partslists/honda-st1100a-1995-s-australia-carburetor-component-parts_bigecajs41e__2101_2944.gif

[Asterysk]

I would be fairly confident that it is B.
Item 20 both right hand carbies.
Item 19 both left hand carbies.

CMS parts show this to be true.
https://images.cmsnl.com/img/partslists/honda-st1100a-1995-s-australia-carburetor-component-parts_bigecajs41e__2101_2944.gif

This diagram does confirm that there are two pairs of needles but to me this diagram could be interpreted as the pairs are front-rear also

[Asterysk]

Okay , I'm coming back to option A (front vs rear pairs)


I have found out the term for this is "staggered jetting" , apparently it is commony used on V fours to make the rear cylinders run cooler (richer mix)

It is also used to correct for differing intake lengths or differing cooling on the exhaust headers.

I am not aware of any difference on St1100 air intakes, if we consider the cooling and exhaust headers then the difference if any would be front to rear
 
From my perspective it is possible to read the parts fiche diagram such that the front pair of needles are the same  (and the rear pair are the same but different from the front pair)

[STeveo]

I would be fairly confident that it is B.
Item 20 both right hand carbies.
Item 19 both left hand carbies.

CMS parts show this to be true.
https://images.cmsnl.com/img/partslists/honda-st1100a-1995-s-australia-carburetor-component-parts_bigecajs41e__2101_2944.gif

This diagram does confirm that there are two pairs of needles but to me this diagram could be interpreted as the pairs are front-rear also

Could be, bit confusing.

[ruSTynutz]

A mate of mine has an ST1100 and a Clymer manual so sent me these photos.

Not sure if they'll help or not...

[Asterysk]

A mate of mine has an ST1100 and a Clymer manual so sent me these photos.

Not sure if they'll help or not...

I got excited when I saw the footnote but then after careful examination I realised I was reading the footnote incorrectly ! My friend has a Clymer, I will ask to borrow it and have a good read, looks like it has more info that the Honda Service manual

[Asterysk]

Looks like the fiche diagram may have been drawn this way on purpose i.e. to allow for both possibilities. I found this page in the HSM and it implies that Honda have option for either Left Vs Right or Front vs rear staggered jets