Dual carbs

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#1: Dual carbs Author: sandbuggy , Location: Prescott Post Posted: Sun Jul 07, 2013 09:33 PM
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Where are you guys buying your dual carb kits?

#2: Re: Dual carbs Author: T_Town_Baja , Location: Tucson, AZ Post Posted: Mon Jul 08, 2013 03:49 PM
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What are you looking for?

I usually build the sets myself. I look for webers single or duals that need rebuilt. Pick them up for reasonable price then rebuild them. From there, just pick up a CB Performance dual weber intake/linkage kit and your done. I have picked up dual 44's for as little as $300.

Blaine

#3: Re: Dual carbs Author: sandbuggy , Location: Prescott Post Posted: Mon Jul 08, 2013 05:57 PM
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Nothing in particular, just fishing around at this point. If I do it, then it will be along the lines you described, because the Sandrail isn't worth spending the coin for a complete high dollar setup (just my opinion).

I run a single webber on the 1835 now and it's been this way since the 80's without issues that I can remember. Never lets me down and it's been all over Arizona back country. So I sort of think I should just leave well enough alone. Just can't help but think there is power left on the table, I'm sure there is. Not sure if it's worthwhile or not though.

#4: Re: Dual carbs Author: T_Town_Baja , Location: Tucson, AZ Post Posted: Tue Jul 09, 2013 03:41 PM
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Do you have a single IDF or Progressive?

There is definitely more to gain going Duals, but at the same time prepare to spend some time dialing them in. I just swapped from a single 44 IDF on my brothers 1915 sandrail and went to dual 44 IDF's gained a ton of top end pull at the expense of some lower end grunt (mostly because the 44's are a tad big for that motor)


Blaine

#5: Re: Dual carbs Author: perrib , Location: Chandler Post Posted: Tue Jul 09, 2013 04:45 PM
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I'd keep it simple and leave the single. Any performance gains (which are significant) seem worthless at idle and off idle at 0-10 mpg in rough terrain with dual carbs.

#6: Re: Dual carbs Author: sandbuggy , Location: Prescott Post Posted: Tue Jul 09, 2013 05:19 PM
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Wow, that's horrible mpg. Everything I've heard people are telling me you get better mpg, guess that's not the case?

I've gotten as much as 34 mpg with this thing trail riding. Mainly because we are just cruising at 25-30 mph in 3rd or 4th just barely working the engine. If I horse around it drops a few mpg obviously.
Driving around town here in stop and go traffic I've been getting 26-28 mpg that ranges from 25-55mph speeds. I don't really want to lose too much mpg. I like being able to trail ride all day with the little 10 gallon tank it has.

I was thinking of duals because I thought if an engine rebuild was in my future I'd build a stroker and thought this single webber wouldn't be enough?

#7: Re: Dual carbs Author: sandbuggy , Location: Prescott Post Posted: Tue Jul 09, 2013 05:24 PM
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T_Town_Baja wrote:
Do you have a single IDF or Progressive?

There is definitely more to gain going Duals, but at the same time prepare to spend some time dialing them in. I just swapped from a single 44 IDF on my brothers 1915 sandrail and went to dual 44 IDF's gained a ton of top end pull at the expense of some lower end grunt (mostly because the 44's are a tad big for that motor)


Blaine

I run a progressive with electric choke. Dialed it in with a wideband and seems to work flawless, even after sitting all these years. Has alot of low end grunt but seems to run out of steam above 4,000. Has a small cam (can't remember the size) and ported heads. I guess I figured it would pull better up top. Thought the carb might be holding it back.

#8: Re: Dual carbs Author: Dalton , Location: peoria, az Post Posted: Wed Jul 10, 2013 01:57 AM
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perrib wrote:
I'd keep it simple and leave the single. Any performance gains (which are significant) seem worthless at idle and off idle at 0-10 mpg in rough terrain with dual carbs.

I'm not a real carburetor man... So keep that in mind when you read this.. 10 miles to the gallon I'm not sure but I think that you might have something else going on there to cause such poor gas mileage.. I've ridden with many people that run dual carbs depending on the driver they were getting in the high 20s to low 30s for mileage.. Or they could be lying..

Here's what I think I know:
carburetors do not off-road well they don't take the bouncing around and tipping that an off-road vehicle is subjected to.. Most the time it over fills the bowl and causes the carburetor not to function properly or it over fills the bowl and splashes into the throat of the carburetor.. Once you go for fuel injection it's hard to go back to carburetors when I crashed my car I was hanging upside down and the motor was still running and did not even skip a beat it was impressive... it took a couple seconds for me to orient myself and shut the car off..(Side note: if you ever find yourself hanging upside down in your vehicle look to your passenger and decide who is going to unbuckle their seatbelt first and wait until the person exits the vehicle completely before the other person releases his seatbelt... It's a lot tougher to get out of the vehicle when both of you pull your seatbelts at the same time... Trust me Shocked )

dual carburetors are more efficient because there's a shorter distance between the carburetor and the combustion chamber.. When you run a single carburetor the fuel vapor has to travel a much longer distance and has the tendency for the droplets of fuel to join together to make bigger droplets which in turn do not burn efficiently..

One of my motors had dual carburetors on it they were heavily modified so that I could run a blow through turbocharger once I had them dialed in it was sweet.. This is the only experience that I have with dual carburetors..

Dalton

#9: Re: Dual carbs Author: sandbuggy , Location: Prescott Post Posted: Wed Jul 10, 2013 03:45 AM
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Interesting stuff. I've had a little fuel slosh when I really tackle a steep hill and bounce around, but nothing that killed the engine. Usually when coming up the back side from Lake Pleasant to Crown King I sometimes get adventurous. I sort of like that feature though, as it lets me know when I might be reaching my limit, sort of a safety switch before I go too far and roll the thing Laughing
Most of our trail riding is mild stuff and site seeing, ghost town hunting etc...so I always have the family along. Plan to keep the riding mild until I get some better front tires anyway.

Here's a pic. I might be tempted to experiment with dual carbs on it just to compare. Anyone have a size recommendation for a mildly built 1835?


#10: Re: Dual carbs Author: T_Town_Baja , Location: Tucson, AZ Post Posted: Wed Jul 10, 2013 04:08 PM
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Perri is right about the off idle MPG, you have one barrel per cylinder throwing down a lot of fuel and then the accelerator pump adding to that - it can drink. Typical rough terrain driving is all about on and off the gas, feathering etc. I personally prefer high speed desert driving/racing where the Duals come alive.

Duals have netted me better MPG's overall for street driven, but just like any performance motor (turbo, supercharger, etc) - you have to keep your foot out of it. On my cars I always run duals and it sure feels nice to stomp it from a stand still and hear the motor come alive, but again it drinks the gas.

Fuel slosh does happen especially in whoops if your suspension is sub-par. My brothers old rail was victim of that and it would flood out through a bad whoop section if he got crossed up and plowed a few.

For an 1835, stick to a set of dual 40's IDFs and be sure to get a good linkage set. Linkage problems are the number one cause of people hating/raging against Duals.

If you are going stroker, why not go duals? Hell I have a set for my stroker you could try if you want, they are 44's, but I can guarantee when you feel the power, you will not give them back.

Blaine

#11: Re: Dual carbs Author: sandbuggy , Location: Prescott Post Posted: Wed Jul 10, 2013 06:11 PM
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Okay duals it is, I'll give it a shot when I find a setup. Easy enough to swap back and forth and I really would like to experiment with it. A stroker would be in the future if this 1835 ever gives up. Darn things been together since 85ish and still keeps on kicking. Sat for a number of years until this year I brought it out of hibernation, reset the valve lash and tuned it up. So far so good.

We don't really do any high speed desert driving anymore but we love the rail up in the mountain terrain up here because it does cruise along much faster and more comfortably over the rough stuff than the 4x4's we use up here, it cuts our time to Crown King in half, literally. Occasionally I might use a straight stretch to wind it up in a gear or two and have some fun though. Gets a bit fishtaily on loose stuff as it is even in 3rd gear and makes my wife a bit nervous Laughing Makes me wonder just how well it would do with a more powerfull carb setup.

#12: Dual carbs Author: Dalton , Location: peoria, az Post Posted: Sun Jul 14, 2013 02:02 PM
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Sandbuggy,

did you pick up those dual carbs from my friend?



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