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Amal concentric questions
Posted: Wed Jun 18, 2014 5:29 pm
by Jamie G
I've just rebuilt my Amal 376 concentric and I am having some teething troubles. I replaced the float needle but on the temp fuel supply the chamber still overfills and leaks from the tickler. On a related note, the float is marked 'front' but is this front as in facing me when I take the cover off or front as in away from me toward the body of the carb? Any thoughts?
Amal concentric questions
Posted: Wed Jun 18, 2014 5:40 pm
by Alan R
Hi JAMIE---------- you don't say if those items are new or the old - type ones..........I would use the modern viton-tipped float needle and the "stay-up" float with it.......This now has a steel plate which you can adjust to vary the hight of the float...........FRONT usually relates to the front of the vehicle when the carb is fitted.......
Amal concentric questions
Posted: Wed Jun 18, 2014 6:06 pm
by Yorkie
Hi guys.I thought that a 376 was a monobloc,different ball game!!
Amal concentric questions
Posted: Wed Jun 18, 2014 6:59 pm
by Jamie G
Sorry yes it is a monobloc, too much reading about carbs today! The float needle is new and is (I believe) a Viton tip one - a black tip? Float is original and is the old brown-black Amal one. On the monobloc the float chamber is on the side of the carb, hence my question about which way the float sits.
Amal concentric questions
Posted: Wed Jun 18, 2014 8:18 pm
by Mark M
Towards you when fitted.
REgards, Mark
Amal concentric questions
Posted: Wed Jun 18, 2014 8:35 pm
by Alan R
Well ! doesn't that show how much attention I pay ???..........I've only just overhauled and fitted a 376 to my B40 a few weeks back !!....If you have a new side cover there is a little "pip" in the centre and that's the float level required......Float fitting as MARK M said....In our hosts catalogue go to page 278 and look at item 22 ( Needle, seat) .. if this screws down too far it prevents the float from rising fully and you'll get flooding............The beauty of the monobloc is you can do all the adjustments without removing it from the bike..............Downside is it's a bit less efficient than the Concentric.....
Amal concentric questions
Posted: Wed Jun 18, 2014 8:40 pm
by Alan R
Amal concentric questions
Posted: Wed Jun 18, 2014 8:57 pm
by Jamie G
A bit of research says that the fibre washer I've used under the needle seat isn't necessary and will not allow the needle to seat properly, raising the level. I'll try tomorrow.
Amal concentric questions
Posted: Wed Jun 18, 2014 9:27 pm
by Mark M
I was going to say don't use a washer under the float seat but I thought no-one else would make the same mistake as me! And by the way Alan, twin handed Monoblocs on a Mk1 Interceptor are an absolute b$%%£r to work on in situ, that's why I've only just come in from the garage reeking of petrol. Happy though! REgards,Mark
Amal concentric questions
Posted: Wed Jun 18, 2014 9:40 pm
by Bullet Whisperer
The Viton tipped float needles are for the Concentric type carbs - they have a groove in them for that type of float to engage with them. They can be used in Monoblocs, but are of a very slightly different length to the original white nylon types. I once fixed a spluttering Triumph T120R by removing the Viton needles and reverting to the original type white float needles. Regards, Paul.