Keihin CV Carburetor
Tourer
Joined: Sep 2007
Posts: 355
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RE: Keihin CV Carburetor
ORIGINAL: lmarkie
BTW, plugs look real good. Slight tan on 13,000 miles.
BTW, plugs look real good. Slight tan on 13,000 miles.
When reading the plugs to determine the mixture you have to do it in a way that it doesn't get skewd. In other words, to make a long story short. Warm it up real good, install new plugs, then ride in the RPM Range your checking, pull in the clutch, kill the engine and coast to a stop. Pull the plugs and read them.
Your looking for a ahhh, off white, egg shell white. Should be tons of info on reading plugs on the net.
Steps to take in this order.
1st Idle Circuit - With Mixture Screw
2nd Midrange - Needle (can also be affected by a wild idle mixture setting)
3rd Top End - Main Jet Size
Do you know exactly what they did to that carb? Jets only???
Tourer
Joined: Sep 2007
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RE: Keihin CV Carburetor
ORIGINAL: 04harleyboy
I did this on my '04 Dyna as well, big difference. Its a flat slide carb, more performanced based, easier to tune, just a much better carb.
I did this on my '04 Dyna as well, big difference. Its a flat slide carb, more performanced based, easier to tune, just a much better carb.
This doesn't mean there is anything at all wrong with the CV carb. I think the CV is a little more forgiving to weather changes and to altitude changes but that is my opinion and belief.
Elite HDF Member
Joined: Sep 2007
Posts: 4,468
Likes: 12
From: Bluffton, South Carolina
RE: Keihin CV Carburetor
This is an amazing site all of the advice is right on the money, now you just need to decide which direction you are going to go. If you plan no further modifications then the CV should be more than enough carb. What we do for "stage 1" is replace the needle with the '88 sporty one leave the stock jets in and on a light bike/rider we sometimes drill the hole in the slide out one size larger. If you plan to put cams, headwork, etc down the road then maybe you should put the 42 Mikuni on it either way you should be happy with the results.
Road Captain
Joined: Oct 2007
Posts: 634
Likes: 8
From: Plum & Nearly
RE: Keihin CV Carburetor
Buy a Dyno-Jet kit and start from scratch...other than changing the jets you have no other idea what was done to the carb. Such as was the slide spring changed? Was the slide Drilled? Was the main jet pick up tube replaced? Are you running a stock needle or the dyno-jet one? Where are the washers and the clip?
I don't have a lot of money to throw around but I dont have a lot of time to waste chasing problems that could be attributed to someone elses partial work if it were my bike. I would like to know where I am at with the carb. The new kit supplies what you need even including the drill bits and intial adjustment settings and jet recommendations.
Good Luck.
I don't have a lot of money to throw around but I dont have a lot of time to waste chasing problems that could be attributed to someone elses partial work if it were my bike. I would like to know where I am at with the carb. The new kit supplies what you need even including the drill bits and intial adjustment settings and jet recommendations.
Good Luck.
Tourer
Joined: Nov 2007
Posts: 452
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From:
RE: Keihin CV Carburetor
THANK GOD THERE IS ANOTHER CARBURETOR MAN OUT THERE!!!. I did my 02 Road King. The PO had put in 50/200 jets. I went back to 45/190 and raised the stock (N9?) needle with 2 #4 brass washers, low speed adjusted to 2 1/2 turns out. Lots of good info in the carb tech section including cheep jets at J&P cycles. I bought 4 jets just to play with for $2.95 each.
note: The low speed adjustment should be between 2 and 3 turns. Change low speed jet up or down if not in that range. Backing out a little will also help the cough.
note: The low speed adjustment should be between 2 and 3 turns. Change low speed jet up or down if not in that range. Backing out a little will also help the cough.
Tourer
Joined: Sep 2007
Posts: 355
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From:
RE: Keihin CV Carburetor
ORIGINAL: lecomte38
note: The low speed adjustment should be between 2 and 3 turns. Change low speed jet up or down if not in that range. Backing out a little will also help the cough.
note: The low speed adjustment should be between 2 and 3 turns. Change low speed jet up or down if not in that range. Backing out a little will also help the cough.
Elite HDF Member
Joined: Oct 2007
Posts: 4,523
Likes: 1
From: South Florida
RE: Keihin CV Carburetor
I had mine done on my 06 SG by a service tech at harley he used the Dyno Jet Kit, it is working terrific. I dont know how to work on it but if and when it starts to give me trouble amikuni will be there right of way....
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Intermediate
Joined: Oct 2005
Posts: 33
Likes: 0
RE: Keihin CV Carburetor
Well, I've added 2 #4 brass washers under the needle. Like suggested......one thing at a time. Idle screw is set at 1-3/4 turns, 48 low end jet, 195 high end jet. I also put new spark plugs in. I haven't tested it yet because it's still cold and wet here in Georgia. I ride only when it's above 70 degrees and dry. Some of you up north may think we don't ride much down here. I rode the mountains last week at around 70 degress for better than 100 miles.
If this don't work, I may replace the Keihin with the HSR42 Mikuni mentioned. Would the Mikuni easy kit work with my existing choke on my '06 Road King Custom or would I have to buy a cable from Mikuni? Does Mikuni sell a choke cable to fit?
If this don't work, I may replace the Keihin with the HSR42 Mikuni mentioned. Would the Mikuni easy kit work with my existing choke on my '06 Road King Custom or would I have to buy a cable from Mikuni? Does Mikuni sell a choke cable to fit?
Extreme HDF Member
Joined: Sep 2005
Posts: 11,615
Likes: 50
From: Baton Rouge, LA
RE: Keihin CV Carburetor
First, the Thunderslide kit will not hurt mileage if jetted properly. My old Evo RK typically got 50-55mpg in touring trim (loaded TP and saddlebags) on the backroads. In fact, it should enhance mileage 10-15% if you follow the directions in accordance with the model you own. My bike had 42 low, 185 main jets with the needle in the standard position prescribed by the manual.
Further, I installed another TS in a friend's 2002 WG about two years ago and his mileage increased over 20%. I've never heard his bike spit back through the carb, and I ride with him frequently.
Second, based on my nine-year experience with the TS, I would recommend it both for mileage and to eliminate or at least decrease the amount of carb spitting you've been experiencing. Mine only rarely spit back through the carb, even with the low jet as lean as it was. I had the idle adjustment set at 1½ turns out from full seat.
Unless you have a high-HP bike that needs the performance edge the Mikuni might give, I wouldn't recommend it for a stock or even moderately modified bike. The CV is an excellent, durable, reliable carb that will provide great performance if configured properly. A friend installed one on his TC88 Low-rider, and realized no performance gain compared to his CV, even after being tuned by a reliable tuner in this area.
Further, I installed another TS in a friend's 2002 WG about two years ago and his mileage increased over 20%. I've never heard his bike spit back through the carb, and I ride with him frequently.
Second, based on my nine-year experience with the TS, I would recommend it both for mileage and to eliminate or at least decrease the amount of carb spitting you've been experiencing. Mine only rarely spit back through the carb, even with the low jet as lean as it was. I had the idle adjustment set at 1½ turns out from full seat.
Unless you have a high-HP bike that needs the performance edge the Mikuni might give, I wouldn't recommend it for a stock or even moderately modified bike. The CV is an excellent, durable, reliable carb that will provide great performance if configured properly. A friend installed one on his TC88 Low-rider, and realized no performance gain compared to his CV, even after being tuned by a reliable tuner in this area.