Carburetor options for Atlas?

Johnnymac

Johnnymac

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Oct 8, 2011
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Hi Guys,

I actually got some time today to play with my Atlas in the garage. My throttle is really sticky so the next job on my list was to lube the cables and clean the Monobloc carbs really well. Well as it turns out the slides are worn and warped and the bodies are a bit warped too. I am thinking about getting new slides and repairing the bodies. That shouldn't be too difficult, but I was wondering if there is a good alternative that I could get. On my Commando I have the Mikuni. It works fine rides great but is a pain to start when cold. It floods rather easily. Is there an aftermarket option that anyone recommends for Atlases? What about the new Amal Premiers?

Thanks!
 
Concentric will work and a Premier in correct size would work great..
 
Frankly, I have no personal experience with concentrics, or Mikunis, only know what others have reported, but my "guts" says to stick with the monoblocs. Get them resleeved if necessary. When properly set-up, I think there is no reason to want anything else. I do not think the concentric offers any advantage, despite claims that fuel level "is more constant".... it is a design that is of more cost benefit to make, rather than of performance. That is my opinion ...

When you say yours are "warped", do you mean "out of round"? Mine are too... about 6 thou, but I do not yet see any tendency to have an irregular idle. You say you are considering "repairing the bodies" ..... how? I am mulling over what to do about my 6 thou.

My slides get sticky from non - use. Recently I sprayed them with NAPA graphite-silicone lock spray. It definitely slickened them up, adheres well, hopefully will mitigate further wear, and hopefully will not wear off in 100 miles.

Slick
 
I'm with Slick.

I don't know what a Concentric feels like on the Atlas, but I found the Monobloc to be better overall than the Mikuni. The Mikuni may not have the slight hesitation that an Amal has when cracking the throttle, but the engine seems to run so much smoother with the blocs. The biggest down side with Amals is the maintenance, IMO.

Scott
 
texasSlick said:
Frankly, I have no personal experience with concentrics, or Mikunis, only know what others have reported, but my "guts" says to stick with the monoblocs. Get them resleeved if necessary. When properly set-up, I think there is no reason to want anything else. I do not think the concentric offers any advantage, despite claims that fuel level "is more constant".... it is a design that is of more cost benefit to make, rather than of performance. That is my opinion ...

When you say yours are "warped", do you mean "out of round"? Mine are too... about 6 thou, but I do not yet see any tendency to have an irregular idle. You say you are considering "repairing the bodies" ..... how? I am mulling over what to do about my 6 thou.

My slides get sticky from non - use. Recently I sprayed them with NAPA graphite-silicone lock spray. It definitely slickened them up, adheres well, hopefully will mitigate further wear, and hopefully will not wear off in 100 miles.

Slick
Click to expand...

My slide on the right carb... the 389/219 is really egg shaped. I am going to my local shop (Donelson cycles) this week to get a new slide to see if that helps. My neighbor is a career brit bike mechanic and has seen thousands of Monoblocs in his day. He says that over time, heat and over tightening can warp (or out of round) the bodies and the flange. He said that a simple pair pf pliers and pressure can reshape the bodies. (I wouldn't attempt that -I'd let him do it for me).

I did get some of that graphite lube and it did not help since my slides are so worn and egg shaped. Hopefully a new slide will solve my issues. I really don't want the expense of buying a new carb right now. My left carb seems OK for now. Fingers crossed.
 
Put a set of PWK carbies on it, Jim would set them up for your bike, they work so well with a maggie.

Ashley
 
Johnnymac said:
Hi Guys,

I actually got some time today to play with my Atlas in the garage. My throttle is really sticky so the next job on my list was to lube the cables and clean the Monobloc carbs really well. Well as it turns out the slides are worn and warped and the bodies are a bit warped too. I am thinking about getting new slides and repairing the bodies. That shouldn't be too difficult, but I was wondering if there is a good alternative that I could get. On my Commando I have the Mikuni. It works fine rides great but is a pain to start when cold. It floods rather easily. Is there an aftermarket option that anyone recommends for Atlases? What about the new Amal Premiers?

Thanks!
Click to expand...

The problem is fitting twin carbs and an aircleaner without bolting carbs directly to the head. I have an option setup on a Atlas but I had to modify the oiltank to clear the air cleaners. If you can do without the aircleaners the easy to adjust Keihin dual smoothbores will fit. Takes special short manifolds from Mic Hemmings.

See them on an Atlas in the video.

[video]https://youtu.be/ZQ4vGEKAVTc[/video]
 
You can fit Amal Premieres /Concentrics and a K&N two hole filter. Britcycle has the correct K&N for the job. It is a tight fit, but it does go.


Carburetor options for Atlas?[/URL
Glen
 
They run much better with manifolds (the longer the better). That requires a Manx type oil tank. Expensive but its the best way to go. Anyone have a line on affordable alum Manx type oil tanks to fit an Atlas?
 
jseng1 said:
They run much better with manifolds (the longer the better). That requires a Manx type oil tank. Expensive but its the best way to go. Anyone have a line on affordable alum Manx type oil tanks to fit an Atlas?
Click to expand...

I bought one on ebay from a seller doflicky104 last year for $275 shipped from the UK. It is extremely well made. The only problem was the seller/manufacturer's communication. It took almost 4 months to receive. (Which would have been OK if he had communicated it from the beginning).

Carburetor options for Atlas?
 
People think nothing of paying out for good tires which wear out, but still run there bikes on 50 year old carbs..!! For the price of a good tire you can buy yourself a new Amal Monobloc carb. No need to get the old one sleeved etc, go on treat yourself and your bike. http://amalcarb.co.uk/monobloc-series.html
 
Horror said:
People think nothing of paying out for good tires which wear out, but still run there bikes on 50 year old carbs..
Click to expand...

Not a good comparison ?

Tires wear out and become hard or dangerous even.
But carbs can be rebuilt back to as good as new.
And its satisfying keeping the original parts serviceable....

But we take your point that new carbs are available.
 
Rohan said:
Horror said:
People think nothing of paying out for good tires which wear out, but still run there bikes on 50 year old carbs..
Click to expand...

Not a good comparison ?

Tires wear out and become hard or dangerous even.
But carbs can be rebuilt back to as good as new.
And its satisfying keeping the original parts serviceable....

But we take your point that new carbs are available.
Click to expand...

I think it's a good comparison, a carb is a wear and tear item the same as a tire but people will run there bikes with worn out carbs. A new set transforms the bike. When people are talking about buy new Mikuni's to put on it, they obviously aren't bothered about keeping original carbs.
 
A worn tire can pitch you on your ear - or worse.
How can you even remotely compare that with a worn carb....

I've got several redone carbs, from the 30s and 40s.
They now function like new again.

Show me where I can get 30s or 40s tires back to new again ?
I have several possible candidates - although they are getting shabbier by the year !
 
What I am saying is a carb is a consumable item, like a tire or a chain and sprockets and should be replaced (or restored) not just run for 50 years and then say Amal carbs aren't very good.

If a tire's worn out, you wouldn't say this tire's crap the bike doesn't handle, you'd change it for a new one. But with a carb it can be worn out and you have a bike with poor performance, bad fuel consumption etc and people will say Amals are crap. I didn't say you couldn't sleeve your old carb and that's fine for carbs you can't get any more, but you can still get Monobloc's and for the price they are they're good value.
 
Johnnymac said:
jseng1 said:
They run much better with manifolds (the longer the better). That requires a Manx type oil tank. Expensive but its the best way to go. Anyone have a line on affordable alum Manx type oil tanks to fit an Atlas?
Click to expand...

I bought one on ebay from a seller doflicky104 last year for $275 shipped from the UK. It is extremely well made. The only problem was the seller/manufacturer's communication. It took almost 4 months to receive. (Which would have been OK if he had communicated it from the beginning).

Carburetor options for Atlas?
Click to expand...

What about an oil tank with a side cap so you can use an Atlas type seat?
 
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