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Re:Hypercharger bike is running to rich fouling plugs
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TOPIC: Re:Hypercharger bike is running to rich fouling plugs
#1027043
brianis (User)
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Re:Hypercharger bike is running to rich fouling plugs 1 Month, 3 Weeks ago  
Iím at 4600 ft 2.0 air jet 37.5 pilot 157.5 main started with a 190 and have stepped down in increments seemed to get better for a bit then rich and 4th notch down on my needle tried the the third and it ran horrible has a hc which I have unhooked the flaps so acts as a aircleaner now v&h longshots I just last night put a new air intake on it and couple months ago put the barons pms screw in. Any help would be great because Iím now getting tired of it and looking to get a ultra but plan on keeping the rs. Was looking at a different air cleaner but want something that looks good for the price maybe if I force more air in I can lean it out but donít want a stupid spike looking air cleaner on the bike any recommendations appreciated
 
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#1027059
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Re:Hypercharger bike is running to rich fouling plugs 1 Month, 3 Weeks ago  
My first question would be how did you determine the top air jet was 2 mm? Did you replace it with an actual 2 mm jet?

From what I've read here the Road Star fuel mileage will increase with elevation when the stock carb is used. I remember my mileage increasing when I rode up to Cheyenne one year. So, could someone have replaced the diaphragm spring with a weaker one? Or even have left it out although I'm sure you would have noticed that.
 
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#1027063
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Re:Hypercharger bike is running to rich fouling plugs 1 Month, 3 Weeks ago  
Yes I replaced it with oem jet and spring is there and in good shape
 
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Re:Hypercharger bike is running to rich fouling plugs 1 Month, 3 Weeks ago  
If you check the float level using the Yamaha method, how high is the fuel level, above the carb to bowl mating surface?

Yamaha method is bike upright, as when someone is holding it up, or on a lift. A small clear hose/tube on the bowl drain nipple. The hose held vertically along a corner of the carb on the manifold side. Open the bowl drain screw, and let the hose fill with fuel. The spec calls for 4 to 5 mm above the carb to bowl mating surface.
 
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#1027067
brianis (User)
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Re:Hypercharger bike is running to rich fouling plugs 1 Month, 3 Weeks ago  
i usually adjust the float just below the bowl seal i can go back in and check the adjustment again
 
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#1027068
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Re:Hypercharger bike is running to rich fouling plugs 1 Month, 3 Weeks ago  
The below the seam spec was published in the original manual and corrected in 2000 to 4-5 mm's above the bowl seam.

Since it has always run rich my question about the diaphragm spring being a weaker one could make a difference. No way to tell without an original to compare it to. The part # is 4KM-14933-00-00 and they're only about 8 bucks.
 
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#1027082
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Re:Hypercharger bike is running to rich fouling plugs 1 Month, 3 Weeks ago  
How does the diaphragm spring work other then putting pressure down on the diaphragm which works off of vacuum if I understand right
 
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texasscott1 (User)
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Re:Hypercharger bike is running to rich fouling plugs 1 Month, 3 Weeks ago  
The diaphragm works off of a pressure difference. At altitude, and lower pressure, at a given throttle position the spring will keep the slide at a lower position than it would be at say sea level. This lower position keeps the velocity through the carb approximately the same as it is at a lower altitude. Thus the term "constant velocity". The velocity of the air creates the low pressure necessary to allow fuel to be pushed up through the main jet. At higher altitudes with the slide in a lower position not as much fuel will be pushed through the jet so it takes a higher throttle setting than at sea level to get the same power.

As altitude increases it becomes harder for the outside pressure to compress the spring. Our bikes are supposed to be good to about 10,000 feet although I've read of those going higher. Because of its construction the stock carb can operate at high altitudes without any black smoke although the power will be reduced.

If I were in your shoes I would at least try replacing the spring with a known stock one, couldn't hurt. I have read where cutting the spring or weakening it is something people have tried to somehow get more power, doesn't make sense but it has been done. Good luck.
 
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#1027106
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Re:Hypercharger bike is running to rich fouling plugs 1 Month, 3 Weeks ago  
Something else I just thought of. If you have the diaphragm out again remove the main jet and push the emulsion tube out and check the air holes. There are articles about emulsion tubes being worn out by the needle but since ours are made of steel I don't think that can happen. Be careful when replacing it, it's keyed to one position and the shroud is pointed off center, don't try to force it back.

Also make sure the main air jet at the mouth of the carb is open and also that the secondary pilot air jet at the mouth of the carb hasn't been plugged. You should be able to place your finger over the pilot air jet at the mouth of the carb and hear a change in the idle. If not then that circuit is closed for some reason. It leads directly to the coasting enricher.
 
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#1027107
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Re:Hypercharger bike is running to rich fouling plugs 1 Month, 3 Weeks ago  
texasscott1 wrote:
Something else I just thought of. If you have the diaphragm out again remove the main jet and push the emulsion tube out and check the air holes. There are articles about emulsion tubes being worn out by the needle but since ours are made of steel I don't think that can happen. Be careful when replacing it, it's keyed to one position and the shroud is pointed off center, don't try to force it back.

Also make sure the main air jet at the mouth of the carb is open and also that the secondary pilot air jet at the mouth of the carb hasn't been plugged. You should be able to place your finger over the pilot air jet at the mouth of the carb and hear a change in the idle. If not then that circuit is closed for some reason. It leads directly to the coasting enricher.


I have seen the coasting enrichers get stuck in the bore and cause issues Might want to also check that if you are in there.
 
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