Joe Minton's carb set up
#1
11-08-2010, 06:32 PM
Joe Minton's carb set up
How many are using Joe Minton's carb set up described below? I recently had a carb issue and ended up removing it and cleaning it up. Bike runs good but mileage is not so hot. I have a Dynojet kit that Minton mentions in his article as not being good for mileage and will get worse over time as the brass needle wears in the the brass jet. My bike is a 2001 Night Train with K&N filter and V&H big radius pipes, and I don't know how long my kit has been in there but he mentions a drop as much as 10mpg is not uncommon if I remember right. I got 39 today on fillup. I was getting mid 40's before attending to the carb but had noticed that it had been dropping some before it flooded the engine. I am planning on ordering stock main/slow yets, and a new needle valve and the jet needle Minton mentions below. I have not adjusted the idle mixture so maybe I should try that first. Here's Joe's recommendation for reference:
To get your Harley's stock carb right, follow these instructions:
l. Buy and install a stock jet needle for a 1988 or '89 1200 Sportster (H-D Part No. 27094-88). This needle was developed for the early Sportster Keihin CV carb that was not equipped with an accelerator pump. As such, it is richer in the off-idle to ¼-throttle range and works just right.
2. Remove the soft aluminum plug covering the idle mixture screw. Back the screw out to slightly richen the idle mixture (½ to 1-½ turns will do it).
DO NOT do any of the following:
Do Not change the main jet; the stock one is just right with a free-flowing air cleaner and mufflers. Yep, the stock main jet is rich. If you find this hard to believe, use the main jet test in the Mikuni manual to see for yourself. You see, the main jet size is not controlled by emission testing and the government is not very interested in mixtures at full throttle. The factories are free to use any main jet they want and, for some reason, all the stock bikes I have tuned over the past 25-plus years have had somewhat rich main jets, including Evo and Twin Cam Harleys.
Do Not change the slow jet; the stock one is just right with an open air cleaner and free-flowing mufflers.
And Do Not install straight, open pipes, especially long ones. If you do, forget everything I've said. Straight open exhaust-equipped engines run poorly in the 2,000- to 3,500-rpm range and no amount of carb tuning can fix that.
-- Joe Minton
To get your Harley's stock carb right, follow these instructions:
l. Buy and install a stock jet needle for a 1988 or '89 1200 Sportster (H-D Part No. 27094-88). This needle was developed for the early Sportster Keihin CV carb that was not equipped with an accelerator pump. As such, it is richer in the off-idle to ¼-throttle range and works just right.
2. Remove the soft aluminum plug covering the idle mixture screw. Back the screw out to slightly richen the idle mixture (½ to 1-½ turns will do it).
DO NOT do any of the following:
Do Not change the main jet; the stock one is just right with a free-flowing air cleaner and mufflers. Yep, the stock main jet is rich. If you find this hard to believe, use the main jet test in the Mikuni manual to see for yourself. You see, the main jet size is not controlled by emission testing and the government is not very interested in mixtures at full throttle. The factories are free to use any main jet they want and, for some reason, all the stock bikes I have tuned over the past 25-plus years have had somewhat rich main jets, including Evo and Twin Cam Harleys.
Do Not change the slow jet; the stock one is just right with an open air cleaner and free-flowing mufflers.
And Do Not install straight, open pipes, especially long ones. If you do, forget everything I've said. Straight open exhaust-equipped engines run poorly in the 2,000- to 3,500-rpm range and no amount of carb tuning can fix that.
-- Joe Minton
#2
11-08-2010, 07:27 PM
Join Date: Jan 2007
Location: along the shore of Mishigami
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My carb is set up pretty close to that. When the motor was stock I dialed the A/F mix to 2 turns and instead of the sportster needle (tried it, didn't care for it) I shimmed the needle. Two years on my set up no issues. 49 mpg on the highway, two up and 40 around town. The 95" kit with cams the fuel mix is at 2.5 turns. Original jets.
#4
11-09-2010, 11:20 AM
Outstanding HDF Member
Both of my carbed bikes needed jetting opened up from stock.
The 03 FXD has the DynoJet kit installed and revised jetting also. 40 MPG.
The 04 883 Sportster has the 89 1200 needle and revised jetting. 50 MPG.
The 03 FXD has the DynoJet kit installed and revised jetting also. 40 MPG.
The 04 883 Sportster has the 89 1200 needle and revised jetting. 50 MPG.
#7
11-09-2010, 12:41 PM
How many are using Joe Minton's carb set up described below? I recently had a carb issue and ended up removing it and cleaning it up. Bike runs good but mileage is not so hot. I have a Dynojet kit that Minton mentions in his article as not being good for mileage and will get worse over time as the brass needle wears in the the brass jet. My bike is a 2001 Night Train with K&N filter and V&H big radius pipes, and I don't know how long my kit has been in there but he mentions a drop as much as 10mpg is not uncommon if I remember right. I got 39 today on fillup. I was getting mid 40's before attending to the carb but had noticed that it had been dropping some before it flooded the engine. I am planning on ordering stock main/slow yets, and a new needle valve and the jet needle Minton mentions below. I have not adjusted the idle mixture so maybe I should try that first. Here's Joe's recommendation for reference:
To get your Harley's stock carb right, follow these instructions:
l. Buy and install a stock jet needle for a 1988 or '89 1200 Sportster (H-D Part No. 27094-88). This needle was developed for the early Sportster Keihin CV carb that was not equipped with an accelerator pump. As such, it is richer in the off-idle to ¼-throttle range and works just right.
2. Remove the soft aluminum plug covering the idle mixture screw. Back the screw out to slightly richen the idle mixture (½ to 1-½ turns will do it).
DO NOT do any of the following:
Do Not change the main jet; the stock one is just right with a free-flowing air cleaner and mufflers. Yep, the stock main jet is rich. If you find this hard to believe, use the main jet test in the Mikuni manual to see for yourself. You see, the main jet size is not controlled by emission testing and the government is not very interested in mixtures at full throttle. The factories are free to use any main jet they want and, for some reason, all the stock bikes I have tuned over the past 25-plus years have had somewhat rich main jets, including Evo and Twin Cam Harleys.
Do Not change the slow jet; the stock one is just right with an open air cleaner and free-flowing mufflers.
And Do Not install straight, open pipes, especially long ones. If you do, forget everything I've said. Straight open exhaust-equipped engines run poorly in the 2,000- to 3,500-rpm range and no amount of carb tuning can fix that.
-- Joe Minton
To get your Harley's stock carb right, follow these instructions:
l. Buy and install a stock jet needle for a 1988 or '89 1200 Sportster (H-D Part No. 27094-88). This needle was developed for the early Sportster Keihin CV carb that was not equipped with an accelerator pump. As such, it is richer in the off-idle to ¼-throttle range and works just right.
2. Remove the soft aluminum plug covering the idle mixture screw. Back the screw out to slightly richen the idle mixture (½ to 1-½ turns will do it).
DO NOT do any of the following:
Do Not change the main jet; the stock one is just right with a free-flowing air cleaner and mufflers. Yep, the stock main jet is rich. If you find this hard to believe, use the main jet test in the Mikuni manual to see for yourself. You see, the main jet size is not controlled by emission testing and the government is not very interested in mixtures at full throttle. The factories are free to use any main jet they want and, for some reason, all the stock bikes I have tuned over the past 25-plus years have had somewhat rich main jets, including Evo and Twin Cam Harleys.
Do Not change the slow jet; the stock one is just right with an open air cleaner and free-flowing mufflers.
And Do Not install straight, open pipes, especially long ones. If you do, forget everything I've said. Straight open exhaust-equipped engines run poorly in the 2,000- to 3,500-rpm range and no amount of carb tuning can fix that.
-- Joe Minton
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#8
11-09-2010, 01:11 PM
Outstanding HDF Member
The Sportster needle mentioned will not work with a Mikuni. It is a CV carb needle.
#10
11-09-2010, 01:47 PM
No Mikuni...yet. I have the CV carb on the bike with the dynojet kit in it. Curious as to what the issue would be with the older Sportster needle and if the needle is shimmed or not. Joe doesn't mention that in the article I sited.