Holley 5200 single carb conversion.

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MikeNTexas
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Holley 5200 single carb conversion.

#1

Post by MikeNTexas »

I am building a GL1100 using a 83 frame and just about everything else from a 80. I was getting ready to rebuild the factory carbs when I ran across an almost new hardly used Holley 5200. This is supposed to be a copy of the Weber 32/36.

Since this was an experiment I went the cheap route and build a manifold from parts on hand. I used a piece of 2x2 square tubing for the plenum and some 1-5/8 roll bar tubing for the runners. Its a little heavier than it needs to be but it was free.

The carb came with an adapter to a smaller bolt pattern manifold and it worked out perfect since the carb needed to be raised some for clearance purposes so I built the manifold to fit the adapter.
intake raw.jpg
intake with carb.jpg
I removed the cable attachments and bellcrank from a hopelessly seized up set of 1100 carbs I had laying around and attached them to the Holley.
carb cable.jpg
carb cables.jpg
carb installed.jpg
I had the fuel tank off to get it cleaned so I hooked up a small fuel tank mounted high enough to gravity feed. After giving the carb time to fill, giving the carb a couple of pumps and observing a good stream from the pump nozzles I hit the starter button. I was awarded with instant startup and a decent idle! After checking for vacuum leaks and fine tuning the idle mixture I called it good.

After getting the tank cleaned and installed along with all of the other parts necessary to make it a complete motorcycle it was time to go for a ride. Easing off from a dead stop proved to quite acceptable. After riding it long enough to get it up to a decent operating temp it was time for some hard pulls.

Opening the throttle wide open resulted in a serious bog but when letting off I noticed a sudden surge in power before the throttle closed. I then slowly rolled into the throttle and the bog was eliminated and as rpm's increased it was able to take the whole throttle. With some experimentation with the throttle I found it performed very well and seemed to have more power than my finely tuned 75 GL1000.

I'm sure some more fine tuning by re-jetting may show some improvements but I am going to leave it as it is for now and ride it a while.
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Last edited by MikeNTexas on Fri May 14, 2021 1:15 pm, edited 1 time in total.
1975 GL1000 (it’s a keeper)
1983 GL1100 Custom (sold)
1976 GL1000 Project (finished and sold)
Another1976 GL1000 Project in the works
wannabridin
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Re: Holley 5200 conversion.

#2

Post by wannabridin »

Does that carb have an accelerator pump?
MikeNTexas
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Re: Holley 5200 conversion.

#3

Post by MikeNTexas »

Yes it does
1975 GL1000 (it’s a keeper)
1983 GL1100 Custom (sold)
1976 GL1000 Project (finished and sold)
Another1976 GL1000 Project in the works
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ericheath
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Re: Holley 5200 single carb conversion.

#4

Post by ericheath »

Others have had luck using a 2barrel to one barrel adapter to centralize the charge and keep the velocity up. It might be that the height helps too.

HOTT used it on his and several others have used it with good results. I think yours is a progressive and would give uneven mixtures for front and rear cylinders.

You would need to make a one hole plate on top of your manifold.
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77 WING, 1200 engine with 77 heads, cams, gl1100 foot pegs, Magna V65 front end, 764A carbs, [-gone Suzuki M109 monoshock--, replaced with gl1100 shocks] gl 1200 swing arm, gl1500 final drive, wheel and rear brakes Valkyrie seat, Meanstreak tank, Sportster pipes, Power Arc ignition off crank.
77 Wing. black
83 Wing, in pieces
"Continuing education is important even if the subject matter is fairly useless (as in this case)."---Greg Foresi
wannabridin
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Re: Holley 5200 single carb conversion.

#5

Post by wannabridin »

I started looking into the Holley 5200's and that led me down a rabbit hole that shows Holley makes a 325 CFM 2 BBl w/ vacuum secondaries as well (made for a triple deuce setup for some vintage cars), in case that's an option for some (https://www.holley.com/products/fuel_sy ... /0-80683-1). Next step is figuring out how to heat up the manifold eh?
MikeNTexas
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Re: Holley 5200 single carb conversion.

#6

Post by MikeNTexas »

wannabridin wrote: Fri May 14, 2021 4:27 pm I started looking into the Holley 5200's and that led me down a rabbit hole that shows Holley makes a 325 CFM 2 BBl w/ vacuum secondaries as well (made for a triple deuce setup for some vintage cars), in case that's an option for some (https://www.holley.com/products/fuel_sy ... /0-80683-1). Next step is figuring out how to heat up the manifold eh?
The Holley 2bbl pictured in your link is a straight 2bbl. Both barrels open at once.
1975 GL1000 (it’s a keeper)
1983 GL1100 Custom (sold)
1976 GL1000 Project (finished and sold)
Another1976 GL1000 Project in the works
ob1quixote
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Re: Holley 5200 single carb conversion.

#7

Post by ob1quixote »

I scavenged heat for my manifold by wrapping the manifold and coolant crossover tubes with a rubberized aluminum adhesive insulation. Even used grip heaters wired to an electronic programmable thermostat.

The thermostat also had a thermometer function, so I know for a fact that the manifold will chill with the fuel air flow, as well as know the insulated manifold heats up nicely when the motor comes up to temperature!
1979 GL1000
2001 DRZ400
1983 CR480
And a few late '60's - early '70's British thumpers
wannabridin
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Re: Holley 5200 single carb conversion.

#8

Post by wannabridin »

ob1quixote wrote: Sun May 16, 2021 2:05 am I scavenged heat for my manifold by wrapping the manifold and coolant crossover tubes with a rubberized aluminum adhesive insulation. Even used grip heaters wired to an electronic programmable thermostat.

The thermostat also had a thermometer function, so I know for a fact that the manifold will chill with the fuel air flow, as well as know the insulated manifold heats up nicely when the motor comes up to temperature!
Interesting approach! What temps do you keep it set at? Whats your long term review on using it?
ob1quixote
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Re: Holley 5200 single carb conversion.

#9

Post by ob1quixote »

I set the thermostat to 90 degrees. When the coolant comes up to temperature, 140-150 was easy. I cut away some insulation wrap to drop it to 110-120
1979 GL1000
2001 DRZ400
1983 CR480
And a few late '60's - early '70's British thumpers
wannabridin
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Joined: Tue Jan 19, 2010 12:40 pm
Location: Hurst, TX

Re: Holley 5200 single carb conversion.

#10

Post by wannabridin »

Pics!!!!
ob1quixote
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Re: Holley 5200 single carb conversion.

#11

Post by ob1quixote »

Mine, or the OP?
1979 GL1000
2001 DRZ400
1983 CR480
And a few late '60's - early '70's British thumpers
wannabridin
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Posts: 668
Joined: Tue Jan 19, 2010 12:40 pm
Location: Hurst, TX

Re: Holley 5200 single carb conversion.

#12

Post by wannabridin »

yes
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taunusrainer
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Re: Holley 5200 single carb conversion.

#13

Post by taunusrainer »

Did anyone test a Weber 32 or 38 DGAS?
It has 2 symmetrical barrels and two throttle butterflies opening sychroneously.
Might be a good design for the flat four, was originally designed for Ford V6.
1976 GL1000 test mule
1977 GL1000 in parts, rebuild in progress
1980 GL1100 Interstate

1969 Ford 17m 2.3V6
1976 Ford Cortina 2.3V6 (Propane)
1990 Mustang 5.0 7up conv.
1994 Volkswagen Polo (Propane)
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