Monobloc jets and oil

Biscuit · Post by **Biscuit** » Mon Sep 13, 2004 2:24 pm

Hi Neville,

I assume you meant 'Alan' The diameter of the 1/16" slide is 1- 5/16". However all this may be academic, see my further offer sent via E-Mail.

SPRIDDLER · Post by **SPRIDDLER** » Tue Sep 14, 2004 3:41 pm

Hi Alan (No not Dave, Trig.)
Well it's a 1" inlet stub so can only assume carb has always been 1".
I guess I shouldn't assume it's always been this small (as the actress said to the........) I suppose, as I don't know where it's been (as the actr.....).
I wonder if, in spite of the sooting it might be running weak! The new exhaust pipe (which was nicely bright chromed) has begun to blue for the first foot out of the head after only about 200 miles. Is this normal?

Biscuit · Post by **Biscuit** » Tue Sep 14, 2004 8:28 pm

Earlier in the forum I quoted the '55 G3 has having a 1-1/16" bore carburettor, why I chose the'55, God knows. The 46 - 54 G3's had 1" bore carbs. My G3 has a 1" bore, but the spares book offers a 1-1/16" bore spacer. However in the back of the same manual (the large one from the club) tells us that G3's from 45-58 all had 1" carbs.

Exhaust blueing, I'm no great shakes at carb. tuning, But in 50 years (with a few gaps) I have never suffered from this. My last project but one, a 400/4 with its four carbs gave me a one in four chance of getting it wrong - but no blued pipes. Could it be to do with exhaust valve timing or tight tappet clearances. Come in the experts!!!.

lawrence · Post by **lawrence** » Tue Sep 14, 2004 9:41 pm

Errrr, I am no expert but would think exhaust blueing is more likely to be due to ignition timing too far retarded than to a slightly weak mixture. If running on super unleaded there is usually no ned to retard the ignition from standard. Having said that, my Triumph has always blued its pipe despite timing spot on and a slightly rich mixture though i think they are thinner guage than AMCs

Lawrence [}:)]

Eric · Post by **Eric** » Wed Sep 15, 2004 12:38 am

Lawrence do you mean Retarded? That means the spark occurs later in the cycle nearer to TDC. I always thought that retarding promoted cooler running while advancing could cause things to get hot[?]

g80csp11 · Post by **g80csp11** » Wed Sep 15, 2004 7:50 am

Advanced timing will cause ' pinking ', kick back when you try to start the bike. the ideal timing just avoids pinking. thats why you retard the timing slightly on very long hill under load then advance back up ASAP

Retarded timing will cause hot running , blue exhaust and generally dull performance

Check ant set your timing first , before attempting to adjust the mixture.

SPRIDDLER · Post by **SPRIDDLER** » Thu Sep 16, 2004 10:20 am

Crikey, guys, that'll give me something to work on during my holiday next week.
Would Prozac help?
More next week (My only internet facility is at the office)

phyl · Post by **phyl** » Wed Sep 22, 2004 11:42 am

Hello Neville
Just looked at your query and the helpful correspondence that followed. Thought you might like to have the actual details given by Amal in their "Settings List".
From 1955-61 (the coverage of the list I have) Monobloc type/size/settings for G3LS (and corresponding 16MS) were -
type 376, 1 1/16" internal bore, 1 1/16" at engine end, 210 main jet, 30 pilot jet, 3 1/2 slide, needle pos'n 3, .106 needle jet. Optional air cleaner (listed as 1955-56 0nly) reduced main jet to 200.
1954 was the pre-Mono Type 76, but still with 1 1/16" bore (I have the det'ls if req'd).
From 1946-53 however the bore (and dia at head end) were 1".
We are just trying to unravel a similar problem with our 1954 G3LS. A Monobloc (its no:s suggest orig from a BSA B31) has been fitted with 1" bore, the inlet port on the head however is 1 1/16" - correctly, as from '54 AMC opened out the 350's inlet dia and the carb was matched to it.
Hope this helps.

SPRIDDLER · Post by **SPRIDDLER** » Mon Sep 27, 2004 11:41 am

Thanks Irene. So many variables!!
I have decided to go back to basics and ensure that the ignition settings - timing, points etc and valve clearances are all spot-on, then move forward to the carburation. Well, that's the theory - I just need the patience to do it.
Went ou at the weekend and found I couldn't put the centre stand down.
Discovered that a nut had come off the primary drive drive side of one of the bolts across the frame through the bottom of the gearbox and the bolt had started to slip out, impeding the lowering of the stand. It looks as though I'll have to remove the entire primary chaincase to get at it. One step forward and two back........ (Love it really, hmmmm?)
Best rgds. Neville

lawrence · Post by **lawrence** » Mon Sep 27, 2004 8:04 pm

hi Neville
I have just had the same problem but in reverse. I asembled all the engine and found I could no longer put the stand UP. The studs and nuts are possibe to reach without removing all the primary case but it doestake a long while turning the nut 1/32 turn at a time. Me, about one hour ;o(

Lawrence [}:)]