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Apr 2, 2008 | 12:45 AM

wallybally

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Intermediate

Joined: Dec 2007

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cv carb mod

Hey all:
I got a few questions about CV carb mods. My present carb on a 1991 FLHTC is a S&S super E carb with stock jets. Just had it rebuilt by a good carb guy. While it runs well after warm up it gets bad fuel mileage and you can smell raw gas(lots) in the exhaust. Soooooooo i read up and see you can do some mods on a stock CV (which I got) to make em real good for a relatively stock bike(stage 1 mufflers and ev27 cams). Sooooo...i go to E-bay and see a guy selling modified CV's. Says he'll get you rolling for bout 180 bucks if you trade in your old carb. Fully modified CV job?
1. Anybody done this?
2. Anybody heard of this?
3.Anybody local to this forum who does it?
Thanks WallyBally

Apr 2, 2008 | 01:37 AM

cmcsns

Road Master

Joined: Oct 2007

Posts: 793

Likes: 4

From: Beverly Hills, Fl. Swimmin pools. Movie stars

RE: cv carb mod

Quote:

ORIGINAL: wallybally

Hey all:
I got a few questions about CV carb mods. My present carb on a 1991 FLHTC is a S&S super E carb with stock jets. Just had it rebuilt by a good carb guy. While it runs well after warm up it gets bad fuel mileage and you can smell raw gas(lots) in the exhaust. Soooooooo i read up and see you can do some mods on a stock CV (which I got) to make em real good for a relatively stock bike(stage 1 mufflers and ev27 cams). Sooooo...i go to E-bay and see a guy selling modified CV's. Says he'll get you rolling for bout 180 bucks if you trade in your old carb. Fully modified CV job?
1. Anybody done this?
2. Anybody heard of this?
3.Anybody local to this forum who does it?
Thanks WallyBally

IMO the S&S E is an excellent carb, simple and very tunable. If you can smell gas you are running rich; set up your idle mixture: set idle speed at 1-1500rpm, turn your idle mixture screw (big one in the middle, top) slowly clockwise (lean) until it wants to stall, now, turn it counter clockwise (rich) counting the turns til the rpm starts to drop,stop there, then turn clockwise to the middle of that (example: 3 turns, turn back clockwise 1 1/2 turn) proper mixture should be approx 1/4 to 1/2 turn towards lean from that point. Your intermediate jet will run till 2500 to 3000 rpm at which point it switches to the main jet. You might want to check which jet you have in there, possibly go down a size on the intermediate. All you need for this is a screwdriver, it's free. Or, you can spend $180 and get a carb that may be as good as an S&S, again IMO. Oh yeah, if yoy check the jets.... turn off the gas

Apr 2, 2008 | 01:57 AM

Roadjunkie1

Banned

Joined: Feb 2008

Posts: 1,943

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From: Chicago.

RE: cv carb mod

Quote:

If you're smelling gas from the exhaust, something is very wrong. Either the main jet is too aggressive, or the accellerator pump is too darn rich. Remove the air air filter, turn the accellerator pump adjuster screw all the way in (it's on the right), now open it two turns. Look in the throat of the carb (with the bike off) and crank the throttle, do you see fuel squirting in? If not continue to turn the adjuster clockwise until you see fuel squirting. At that point open it up another 1/2 turn and use that as a starting point. If it is squirting at the two turn point, turn the adjuster counter clockwise until the accellerator pump goes dry and repeat the process I just described. If the bike starts to cough when you accellerate, richen up the accellerator until you hit the sweet spot.

The S&S E carb is a very basic but agressive fuel delivery system. Been running a "G" onmy Evo since 94 and requires constant attention based on barometric pressure, ambient temp and elevation.

On the other hand the CV carb is superior and a darn good carb. Word of caution, purchased a new one and modify it yourself by picking up a jet kit. It's as simple as making toast.

GL Wallybally

Apr 2, 2008 | 06:10 AM

Mick

Road Warrior

Joined: Jul 2006

Posts: 1,532

Likes: 7

From: Rochester N.Y.

RE: cv carb mod

Don't know much about the super E carbs , but here's a link for basic settings.
http://www.nightrider.com/biketech/h...&S_jetting.htm
I personally like the stock CV carbs and run one on mine.
The CV can give you what you want and get good mileage in the process.
My mods are in my sig at the bottom , cost was about $20.00 for ,pilot jet , main jet , and needle.
I think the stock carb can't be beat for what you intend to accomplish.
Good luck , and let us know how/what you did to solve your problem.
I got most of my tuning ideas from the DIY section and careful observation of mileage and plug color.
Mick

Apr 2, 2008 | 11:15 AM

Northside

Road Warrior

Joined: Mar 2007

Posts: 1,396

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From:

RE: cv carb mod

I think you'll be satisfied with a properly jetted stock 40 m.m. C.V. Back in the early 70's everyone was looking for a better carb for Harleys. S&S offered the "B" with no accelerator pump, guys modded Tollotsons, Harley offered the Bendix, old style Mikunis from Branch. I liked S.U.s off Jaguars. They were the only carb I could get to be smooth and clean running with no flat spots or burbles at any rpm. They were a vacuum slide carb with a hugh shiny dome on top. When Harley first offered the C.V. I was amazed, this is an updated S.U. vacuum slide carb. I think they're a great carb, better than an S&S for mild motors. Mikuni HSRs are my favorite now.

Apr 2, 2008 | 11:37 AM

04RoadKing

Outstanding HDF Member

Joined: Aug 2005

Posts: 2,141

Likes: 4

From:

RE: cv carb mod

I've had several different carbs on my RK over the past four years. First the original CV and then I went to the S&S Supper E, then Back to the CV then I got board and bought a new Mikuni 42 it was ok. But I ended up going back to the CV a couple weeks ago becuase I couldn't ever get my bike to run as good as I could with the CV. I know the Mikuni is a great carb but I had better luck tunning the CV. I could rejet theCV in the dark on the side of the road if I had to. The S&S was ok if I was drag racing WFO throttle all the time. There again I'm not the greatest carb tunner with the S&S either. SoI'd pick the CV over all of them. Good luck....