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TOPIC: Re:Poor fuel mileage
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Re:Poor fuel mileage 2 Years, 1 Month ago
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good to know thanks i didnt know it had metal under it.
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Reinie (User)
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Re:Poor fuel mileage 2 Years, 1 Month ago
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I've been down this road with my carbureted 07 Roadstar.... decel backfiring, bad gas mileage, and poor ride-ability. After two guessing attempts to lean it out by Yamaha mechanics, I finally brought it into a local performance shop (Ducati of Mpls) and had it rejetted and dyno tuned. The most significant adjustment was the main jet being changed from 180 to 155. Needle and air adjustments were also needed to get it to behave. |
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Re:Poor fuel mileage 2 Years, 1 Month ago
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Reinie wrote:
The most significant adjustment was the main jet being changed from 180 to 155. Needle and air adjustments were also needed to get it to behave.
Are you sure about the size of the main?
I suspect to run such a lean main it must be rich on the other circuits. 
How's it run at idle? Any black smoke?
Doc
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Re:Poor fuel mileage 2 Years, 1 Month ago
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Reinie, they had to jet yours down that far? If I am not mistaken your elevation is about 700ft right? Sorry guys didn't mean to hijack thread!
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There are OLD BIKERS and there are BOLD BIKERS, but there are NO OLD BOLD BIKERS!
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Reinie (User)
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Re:Poor fuel mileage 2 Years, 1 Month ago
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I have posted the dyno charts and work invoice on the thread "Would you like your bike to run right?". I am at elevation 940'. |
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Re:Poor fuel mileage 2 Years, 1 Month ago
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it surprisingly runs great at idle, it runs great all the way around. it will puff black smoke if i rev it up, in nuetral or running down the road. im thinking it is the other circuits im going to be messing with the other circuits tonight, how many turns out does the manuel call for on the air fuel screw on the bottom??? and i read about an ajust of the accelerator pump which direction would i need to turn that to lean it out?? |
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Re:Poor fuel mileage 2 Years, 1 Month ago
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i am at 229ft elevation, and i havent checked my needle clip setting yet either im going to check all of this tonight
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Reinie (User)
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Re:Poor fuel mileage 2 Years, 1 Month ago
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I paid the price, but the bike is tuned perfectly. No "starting point".... No "rules of thumb".... No "guessing".... The bike starts with choke and requires partial on take off. (I have had a cough on cold engine)Warm engine idle is great. No decel backfiring. Great 30mph cruize down main street. I assume the gas mileage will be improved and less exhaust fumes. It even sounds better. The rich condition made it sound more like a jack hammer. Couldn't be happier. |
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Re:Poor fuel mileage 2 Years, 1 Month ago
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Reinie wrote:
I paid the price, but the bike is tuned perfectly. No "starting point".... No "rules of thumb".... No "guessing".... The bike starts with choke and requires partial on take off. (I have had a cough on cold engine)Warm engine idle is great. No decel backfiring. Great 30mph cruize down main street. I assume the gas mileage will be improved and less exhaust fumes. It even sounds better. The rich condition made it sound more like a jack hammer. Couldn't be happier.
There are a few ways to get your cruise range and idle AFR in the right range. That is to get into the other curcuits. Where you are loosing if I remember correctly, Your HP was real low. Even lower than stock. I would say it is because you are not getting enough gas at WOT to make any HP. I have heard of places that are unfamiliar with this carb jetting in this manner. you must have a massive size pilot jet. The pilot screw on this carb adjust exactly opposite of a idle/air screw on other carbs. On a idle/air turning the screw out is going lean. On our with the pilot screw, out is rich. IMHO a 155 main is too small for any elevation in the US. 
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Last Edit: 2010/04/08 10:46 By davej.
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dave
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