The Carburetter

[LJ.]

A item that has not appeared on this forum yet so I'll kick us off on the subject.

I expect that we all have an Amal Monoblock carb of some sort, various jet sizes, needle settings etc. I dont fully understand the workings of a carb, however, as they are getting old and worn there appears to be some good reproduced ones available. Are they as good as the originals? or are they better? Has anyone bought one and replaced their original? A good website that Burlen has who makes these is found at...

http://www.burlen.co.uk/sidelinkSearch.aspx?sideLinkID=12

It seems that they are very reasonably priced and I may just get one. I have heard of guys resleaving the slider but it is expensive! so I am wondering if a complete new one is the way to go.

Any comments?

Here is a snap shot of my slider, you can see that it's on its way out. Does it look that Bad to you?

[Caretaker]

Hi, good link, and interesting topic. I have some info on the new 276, I'll come back to it. Your slider does -not- look good...

Regards
Erling

[fido]

I have heard of people having problems with these new carbs as sometimes there are drillings which are not drilled deep enough. Not original I know but I would like to get a Mikuni or 2 for my A7. I have a twin carb manifold I bought on Ebay and would like to set this up with a pair of modern carbs and a suitable throttle linkage. Modern parallel twins tend to be linked mechanically but I would think the V twins would have a suitable cable setup. The novelty of leaky Amals wore off for me some years ago.....

[dpaddock]

Your slide LOOKS worn but only some diametral measurements will tell the extent. The plating wear is superficial; if the base metal is not worn and the slide doesn't rattle in the bore of the carb, it's OK for some more riding. I trust you're using an air filter.

The Mikuni VM is a good choice but it's difficult to get it right. It's a copy of the Amal Mk2 which is simpler.

Dual carbs have great bling but getting them act concertedly is nigh impossible. For best rideability, stick to a single carb.

Good luck.

[jfligg]

Hi Erling
  I would like to see the info on the 276 carbs. Thanks Jeff

[a10 gf]

Hi, the new 276 was nearly very nice, except it had a few problems. Probably just bad luck, I can't think all new 276's are like this. The overall quality, finish and casting looked superb, but it had float level problems with flooding, whatever I did didn't cure it enough, + a (small) casting\drilling problem between the carb body & jetblock made it run over-rich at idle\low rpm. But at higher speed it worked perfectly, much better than my old 276. I was offered to exchange it for a new carb but at the time didn't manage to get that done within a normal time limit. So I'm back to my old carb, which is ok, but I miss the extra power and willingness for higher revs I remember for the short time I used the new 276. One day, I think I'll get another new-production 276 and try again.

Regards
Erling

[bsa-bill]

Interesting - I have a problem with a new 389 carb, idle adjustment only seems to make a difference when screwing the adjuster inwards, turning it outwards it goes from lumpy to normal and then just more normal ( does that make sense ), been meaning to remove the fibre washer from under the fuel union on the float chamber although I have heard the new carbs require it to be there, still might be worth a try, if thats not the cause then I think I'm looking at the same airway drilling problem mentioned above
All the best - Bill

[fido]

 Bill, the tickover screw just forms a stop for the slide so once that has bottomed out (assuming there is the correct play in the cable) further unscrewing will make no difference. If the tickover is too fast you may have the wrong slide or a leaky carb. flange joint. Another possibility is that air is getting round the outside of the slide. I've heard that these Burlen carbs have too great a clearance between the slide and the carb. body, much like you would get with a worn out carb.

[dpaddock]

Lordy, the replacement carb folks must simply love this!

Come on; check what you have and THEN make an informed decision (unless you have lots of cash plus an overweening need to buy every darn thing that subsitutes for intelligence).

Sorry - I get carried away now and then.

D/

[bsa-bill]

Hi Fido - by idle adjustment I meant Pilot jet adjustment, sorry my fault, should have been a bit more precise

All the best - Bill

[a10 gf]

Ahhh, great explanation, dpaddock... it was some lack of intelligence that prevented the fitted 276 15\16 to substitute itself for a 1 1\16 all by itself! 

If anybody has for sale an orginal amal 276 1 1\16 rh float, complete & in very good condition, I buy, otherwise I will definitely try one more new-production some day, hopefully they have sorted out some manufacturing problems by now. Anybody else with 276 stories?

Cannot forget the extra power and smoothness the new 1 1\16 gave at higher speeds. In that context it was a great loss to fit the 15\16 again, but at least it has great tickover and no flooding. So all in all, I have both full power and nice idle, just need to switch between the carbs at 2000 rpm while riding...

Regards
E.

[Pollock]

I guess I will throw this in hear...purist will kringe but a dude I know but one of this JRC's on his A65 and is very happy with it.....I think he said it was like $138 US delivered to his door.  I believe all the larger british m/c parts houses are selling them now.
http://www.jrceng.com/gallery/PREVIEW

[jfligg]

WOW I like them.  They look very nice.  Is there any advantages to using these instead of a new AMAL concentric.  Jeff

[BrianDallasTX]

Looks good and if it is good enough for a Vincent then our lowly A10's/A7's should be OK.  What about simply going with a concentric as there are tons around cheap?  Just a thought.  Besides plenty of jets and rebuild kits easily had.