Triumphrat

Kev_England · 07-05-2009, 10:29 AM

The Amal 930 carbs I have on my 68 Bonnie look like the originals. Inside, both had almost same wear and looked identical in terms of dirt and discoloration etc.

However, one had a pilot jet and the other did not. Would this be possible to happen on a brand new bike back in 68? Or has the owner changed one carb over the years (I can't think how this could happen)?

I understand these carbs may or may not have pilot jets -- was there a particular year the made the switch?

Cheers.

Plewsy · 07-05-2009, 10:43 AM

Hi Kev_England,
If you look at the carb body behind the tickler, where it says 930 look for a faint stamping just underneath, its the year of manufacture.

The one with the jet could be a later carb or a mod, if it is a mod the original pilot bush needs to be drilled out.

Kev_England · 07-05-2009, 10:58 AM

Plewsey:
Yep, the markings are sort of different so Im thinking these carbs are from different batches. I can't see 100% but it looks like:

Pilot Jet Carb: 930/21 with an 'R' stamped sideways.
No Pilot Jet Carb: 930/10(?) with '39' stamped sideways (Note: the 39 could be R9 or B5 or something similar - its very faint)

No year stamped. Are these codes? Maybe special codes to confuse the Germans?

Surely no one would 'mod' a carb???!!!!

Plewsy · 07-05-2009, 02:26 PM

The markings are very faint, R for right, L on the left one, the numbers are two digits like 66 or 70 pertaining to year and usually just below 930.
I wonder if your b5 is 65

As a mod that one is perfectly acceptable

in fact if you look closely at the hole with out the jet, I bet its threaded.

epynt1050 · 07-05-2009, 03:37 PM

930 is the carb series and size. 900 series are concentric Mk1. The 30 refers to the body being 30mm. The /21 and /10 are spec to which the were produced. ie cut out, needle position etc. /10 is the Bonnie spec for a left hand carb for 1968/69. Prior to that (ie for 1967) the carbs were Monobloc to DU59319, concentric thereafter (US market only).

930/21 is a BSA spec right hand carb on a 68/69 A65 Lightning or Firebird.

The two carbs started out in different bikes.

Webby · 07-05-2009, 04:16 PM

Quote:

Originally Posted by Plewsy

The markings are very faint, R for right, L on the left one, the numbers are two digits like 66 or 70 pertaining to year and usually just below 930.
I wonder if your b5 is 65

As a mod that one is perfectly acceptable

in fact if you look closely at the hole with out the jet, I bet its threaded.

Hi Plewsy,

I don't want to disagree with you, but I liked your photo so much I went to have a look at my carbs, my R/H is marked 66 just like in your photo and my L/H is marked 67. Thinking this was a bit odd to have 66 & 67 carbs fitted on a 72 bike (I was thinking maybe the casting date) I checked the specs in the workshop manual and the carb types are stated as being Type R930/66 and L930/67 with R930/60 & R930/65 fitted to the single carb models.

Webby

PS: I wasn't looking trying to prove you wrong, after reading your post I thought "cool, I'll go & see if I've got the original carbs on my bike"

Plewsy · 07-05-2009, 04:47 PM

No bother Webby

that pick is from a set of carbs my mate gave me, Funny the other is 67 the carbs on my bike as far as I know the originals have 72 and 73 stamped on them, I assumed it was the date

Webby · 07-05-2009, 04:52 PM

The mystery deepens?
If I saw 72 stamped on my carbs I would assume the it's build year as well

Time for a bit more research I think!
Someone out there will know!

Webby

epynt1050 · 07-05-2009, 04:56 PM

the stamping 72 and 73 are the build spec, not the yr.

Kev_England · 07-05-2009, 04:57 PM

Well lads,
I wish my carbs had the year on them like yours. But, mine do indeed have these strange markings:

I think epynt is on to something. epynt -- could you tell us the source of this information? And thanks very much!!!