2004 yfz dasa jetting issue - Yamaha YFZ450 Forum : YFZ450, YFZ450R, YFZ450X Forums
 
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post #1 of 8 (permalink) Old 05-18-2017, 12:44 AM Thread Starter
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2004 yfz dasa jetting issue

I have an 04 yfz with a full dasa shorty exhaust, and a k&n intake. When I first got the pipe and started jetting the bike was running very rich, the plug was black and it was bogging really bad. I had a 175 main jet in it, 3rd clip from the top on the needle, 2 turns out of a/f screw, with a 45 pilot jet. I went from a 175 main to a 170, then to a 165, then right now it's at a 160. Each time it helped the bog tremendously, but now at the 160 it still bogs a little at almost wot. To me that seems really lean, what could I do to change this? I'm around 1,500 feet above sea level too. Thanks for any help
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post #2 of 8 (permalink) Old 05-18-2017, 11:41 PM
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your main jet controls WOT

so maybe go up one size on the main jet...not sure if theres a 162...try that

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post #3 of 8 (permalink) Old 05-21-2017, 05:20 PM Thread Starter
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I'm thinking I should go down to a 158 main jet but that seems really lean for the mods on my bike. Also i am not sure what needle I'm running because it doesn't say anything on it at all but I'm on the 3rd clip from the top on that, and I'm running with my airbox lid off. Can anyone tell me why it is so lean? There is no popping/backfiring at all and it isn't getting any hotter then it ever has so I'm stumped
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post #4 of 8 (permalink) Old 05-23-2017, 11:16 AM Thread Starter
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post #5 of 8 (permalink) Old 05-23-2017, 03:10 PM
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Man, that sounds way lean. I would think you would be around a 45p -165m, 3rd clip and 2 turns out on the screw. The '04-'05 needles were adjustable from the factory. You can do the zip tie mod which should help the bog.

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Jetting Specs: 42p- 215m-4th clip NCVQ 2.0 out, 0-500'.

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post #6 of 8 (permalink) Old 05-24-2017, 10:12 AM Thread Starter
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The zip tie mods done and I don't get why it's so lean when I had my white brothers exhaust on it ran strong with a 172 main and 4th clip from top on needle
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post #7 of 8 (permalink) Old 05-25-2017, 09:58 AM Thread Starter
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post #8 of 8 (permalink) Old 05-26-2017, 09:28 PM Thread Starter
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