Hi Folks.. I have searched and searched to no avail and I'm about to make myself nuts here. Hoping someone may have some insight on my unique setup.

I have an 04 Road King with the SE103 Stroker, HTCC heads, SE260 Cam running the SE CV51 carb/intake combo.. 15k on the bike and motor, and was a dealer build at time of delivery in 04. It runs like a scalded dog at sea level, but I just cant get it to be happy in and around the elevations I am running in up here in the mountains near Yosemite where I live. Hard to start and miserable low speed manners, not to mention I cant get a consistent idle to save my life which just makes me crazy. I have the full jet kit with the assortment of needles and jets but frankly I am just over this weird, one off carb and would like to move to the HSR45 which I know much better and will have much easier time finding parts. Trouble is the conflicting reports of needed parts. Will I need an intake manifold change and if so to what being that my heads aren't stock I hate to order the wrong part? What AC to use as the unit I currently have is specific to this carb setup? Frankly, it would be nice to get some right side legroom back!

This carb is better suited to the 117 and 120's of the world in my opinion and I don't want to just suffer along with its tantrums. No amount of jetting and needle combo changes have made this any better.

Thanks in advance!
Brian

 

measure the ID of the rubber seal where the carb slides in and post it up, i think that you might be able to get away with using the manifold that you have. once i see your measurement i can measure a Mk 45 that i have at the shop and make sure the numbers look good. the 45 Mikuni, in my opinion, would be an excellent choice for you. once we know that the manifold sizing is good, then you just need to get the Mikuni adapter and you can most likely use your current air cleaner. what kind of AC are you currently using?
m

 

The HSR45 in kit form comes with an air cleaner I thought , they did when I was doing evo conversions with them.

 

I just got called to LA so I wont be able to get it apart until Wednesday. It has the big one that comes with the CV51 Kit as you can see below.

 

The kit I bought has an adapter to use an existing CV AC, but from what I understand this one on the CV51 is a one off and has bigger bolt spacing. If I can get it mounted up it will be easy enough to find something that will work well I think. Maybe Ill get lucky and have some right side leg room!

 

Actually, this begs yet another question. Attached is the kit contents of the CV51 kit. The head breathers are piped into the AC backing plate which may or may not go away. Where do these normally run on a Mikuni as most I have seen are a straight filter or velocity stack? I hate to think of oil dripping out a breather on to the motor is the only solution.

 

There's all kinda stand alone head breather bypass kits out there just for this kinda thing, common and cheap. Or you just plug the holes in the backing plate put a Y fitting in instead routing it back into the breather with some extra hose and run it down under the bike, most common fix. I see the spacer fitting there already.

 

If you want to change over to an HSR45, you'll need the SE manifold for a CV44. It's smaller than the CV51 manifold. The CV51 carb spigot is large. It's larger than and HSR48 spigot.

I do think that with that cam and those heads you won't have much low end. Not sure if an HSR45 will help. It might a little.

The are a couple things you can do to smooth out the intermediate and off idle response.

1. Drill a 3/32 hole in the throttle blade. This allows the blade to close a little more at idle and gives better adjustment on the idle fuel screw. Bobby Woods used to do this but later modified the idle fuel transfer ports in the carb body.

2. Cross drill a second hole in the top of the emulsion tube at the top. Make it the same size the other holes. This slows the intermediate to main jet transition.

It's worth a try,, If you give up I might be interested in the cab and any jetkits you might have..

 

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Tuning carbs is a black art which some of us never master. Find yourself a local indy who knows them and get him to tune it for ya! Works for me.....