AJS & Matchless Owners Club

Evening all

So I have a 626 concentric carb on my G9 and I'm finding it difficult to get the settings correct on the air screw & idle screw. No matter what I do It doesn't seem to idle nicely (I have to stand and open the throttle a little until she's warm. She seems to be over fueling as well... small amount of fuel smoke/smell) plugs are black and sometimes the carb likes to spit...But no matter how I try to adjust the air screw to more lean it doesn't seem to alter anything. Meaning it can be irratic at times. Iv had the carb off and cleaned and replaced with new gaskets/ filter.
Thanks in advance

What carbs do other owners use and can recommend on there G9s. (1953) just thinking of an alternative.

Hi

If you use the Amal website it shows the original garb to be in stock

http://amalcarb.co.uk/carbspec/carburet ... s/id/6664/

Regards Mick

Having tried various, I'm happiest with a 376 monobloc on my Mod 20 (with sloping seat pillar tube, same as yours will have). It'll go on, just, although not as easily as the original Type 76.
For my money, monoblocs are reliable, leak free, easy to tune and altogether better than messing with concentrics on these things. I also recall that a concentric is a very tight fit height-wise, but I may have got that wrong and it may just be a question of a thicker spacer or something.
See pic.

PS I usually remove the battery platform for removal and fitting, makes it a whole lot easier.

Hi thanks for that. Yes the concentric is a very tight fit and there's literally a mil to spare from the banjo bolt to the down frame. What set up would be best to get for the 376 mono? Neeele etc...... many thanks

It is possible to adjust the float height on a concentric by bending the tangs, it shows you how on the Amal/Burlen website. I think float height is your problem. My G9 is fitted with a Monobloc they seem well proven and I am about to put a new one on my 350.

Off top of head this as I can't easily check without taking it to bits! But I am set up, I'm pretty sure, exactly per the data in Neill's book for monobloc variants of the 500 twin. Inch bore, 240 main, 106 needle jet (EDIT - book says 1065, but not easily available), standard needle on 3rd groove, slide cutaway 4. The pilot, (EDIT again here) is 30. As you can see, my carb isn't in the first flush and I have had to make a new screw on lid etc, also slow running screw - but none of that affects the settings. First kick starting, clean running through the range, no problems. No air slide fitted, hole for cable entry blanked off, and no air filter either. (That is always hard on these of course.)
I'll come back later when I've had a read of Neill (which is in the workshop) if any of this is wrong.

although mine is a model 30 i am running a 1" 376 monobloc on it and it runs great .

when i start the bike i will turn up the idle screw by 1/2 turn or more so it idles and then as it gets warmer i reduce it back down .

one tip though , dont leave a cold bike idling with fast idle when its on centre stand on concrete or on a paving slab or bit of board etc or it will move backwards when the idle revs increase as it warms up and if you are near a kerb of edge of concrete etc it may fall off and over on its side .

you may want to look at a 376/34 or a 376/6 , only difference seems to be in main jet , 220 in the 376/34 and 220 in the 376/6

go to burlen fuel systems , carb is £172 new but you may get 5% off if you tell them your member of jampot club .
other than that , e mail them and tell them a mate of trevor gale told you to go to them for a carb and ask if they will give you a discount , i usually get a 5% discount on anything i buy when i mention my mate trev who works there doing the 276 and 389 carbs .
all these for 55-59 G9 .

all the best
ian

Thanks for all the info everyone.