This is a thread for older bikes obviously. I am interested to hear why HD owners remove their CV carbs. Was it for performance issues? I still have mine on, and in the first year installed a "Thunderslide" kit. It has performed flawlessly, and still gets about 50mpg with a cam. I don't believe the CV carb is junk, so save those comments. There are plenty of upsides for CV carb use. Self adjusting for altitude changes for one. Economy for another. If the owner wants to trade off economy for performance, them the S&S, or Mikiuni speaks for itself. I bought an Older Softail Custom with a Mikuni on already, and have now replaced it with a CV carb. (New Take off-I know!) The Mikuni wasn't installed right. The cables were loose and had too much slack. And they were bent right below the right tank for clearance. There was no way to take the slack out any more. The choke sucked, and mileage was not the greatest I must say. It needed to warm up for too long as well. This was an older conversion (Early Mikuni) that just wasn't right for the application. I installed new OEM cables, and the correct OEM manifold with James gasket seals. Now she's good to go! I imagine this is how she was built to run. I didn't install the "Thunderslide" kit again because this bike is going to remain stock.

A good carb conversion back then needed correct cable installation, New choke cables (not S&S) and correct jetting for a tame engine. Mine was running rich for my tastes, and the CV carb is easy to jet for an air cleaner and an after market exhaust. I once spoke with a carb expert who told me the OEM CV carb is jettable for up to 114 inch engines. I know Screaming Eagle made a 40MM CV unit. I have no experience with that.

What are your experiences?

 

Back in my earlier days I used to just re-jet the CV, put on a high flow air cleaner, pipes and call it a day. I vaguely remember a lotta folks would change the needle with a specific Sportster needle (can't remember what) but I never did. Always thought about getting a Mikuni but decided why argue with success?

 

I search out a cv for my Shovelheads, had to do it twice. They work great on the shovel.

 

I don't know much about Shovels. Did the same manifold fit? Was it an easy swap? How about the cables? Any problems there?

 

Wrong cable and needs adapter pressed on the carb. Once I trimmed the outer sheath and made it work

 

When I had my Evo remanufactured by Harley back in ‘02, the rebuilt motor had serious issues, not the least of which was hard starting. After trying everything else, the dealer convinced me that a Mikuni HSR 42 would help. It didn’t, but after another rebuild the carb stayed because, well, why not?

 

Ya that was what I remember. The sportster needle or various kits. I changed emulsion tube cause dealer sold me it. Dunno. I think it warmed up better after that and jetting.

As for getting rid of CV the anti FI folks sweared it was so good you didn't FI for elevations changes and such.

 

Bob Wood of Wood Performance in Cropwell, AL has built a very successful business around the stock Harley CV carb. He also has kits for Shovels if I'm not mistaken. It's been a long time since I've kept up with his evolving business, but it looks like he's manufacturing (or possibly altering stock parts like the carbs? not sure) pistons and cams on his website. The site ain't much to look at, but I met Bob back in the '90s when my partner and I owned a mobile dyno business and Bob used us for testing his creations when he was first getting started, so I know quite a bit about his work ethic and level of knowledge. I sold my half of the dyno business to my partner, and he eventually sold the dyno to Bob, so I know at least at one time, he had his own dyno services in his shop too. Pretty sure he still does, but not positive. My mechanic at Samson V-Twin in Samson, AL, uses Bob's stuff in his custom builds fairly often. But Bob's the guy to go to for info on Harley's stock CV carbs, and what can be done to improve on and/or tweak the design for specific applications.

Blues

 

The CV carb can be jetted so as it runs better, that's for sure. But that plastic fuel inlet that is prone to breaking isn't any fun when it breaks. I tried many different carbs on my 79 shovel and was very happy when i installed the S&S B on it. My 91 softail ran fine with the stock CV on it. But by 92 HD had the carbs so leaned out my 92 would hardly run. Had to run with the choke on for 15 miles before it started to run correctly.
All this got me into looking at the jet sizes between the years of the Evo bikes and they kept leaning them out more and more every year. I installed an S&S E and my Evo and it was like a different bike, and pretty much bullet proof too.

 

My first work with a CV was about 25 years ago. I had read the articles about the Sportster jet, etc. and decided to go for it. It worked and did help my 80 inch run better. But, while I was changing jets, I realized there was so much more that could be done, to enhance this carb. So, after a few months with just the jets, I decided to risk the whole carb and see if my hunch was right. I pulled it apart as far as one can reasonably do. The, with my trusty dremel in hand, I radiused the intake port, getting rid of that molding crease. I polished the slide and tube and did a few other things. I have to say, the throttle response was nothing short of outstanding. When I bought my 98 softail, I had a Screamin Eagle cam installed and the head milled 60 thou, (yes it can be done). I rebuilt the CV carb and installed a set of Screaming Eagle pipes with a Kuryakyn Hypercharger air cleaner. It ran like a scalded Ape. I had an opportunity to take it to Zippers, in Maryland, for one of their open house, dyno days. Dan Fitzmaurice was reading the dyno prints as about 150, or more of us, put our bikes on the machine. As they took my bike off the machine, I walked over to see what the results were. 80 horsepower and 88 pound feet of torque. But best of all was Mr. Fitzmaurice looking at it and saying, "If you can tune a Harley like that, you don't need me"! I didn't install the cam or shave the head and all the changes I made were recommended by Night Rider and another article I had read. So I can't take all the credit. But that CV carb was a part of that tune. I don't think anything else could have done any better.