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Ok, jetting experts, please give advise on jetting starting point.


Jayy

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Ok. I just ordered a DMC alien exhaust package and I need to know where to start with jetting. My shee is bone stock, and I am going to drill two 1" holes in the back area of the airbox lid and put in 1" uni filtered vents. Air filter is stock for now. I live and ride at elevations from 1600 ft minimum to 2500 ft maximum. I am in northeast Tennessee, so it is warm here. I have a sets of 280, 290, and 300 mains to try. Should any of these be close? I have jetted before, but the shee is new to me. Do I have to remove the carb completely to have room to get to the main jets, or can I loosen the hose on both ends and twist the carb enough to get the bowl off? Thanks in advance for your advice. Man, I cant wait to get these pipes! :thanks:

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Ok. I just ordered a DMC alien exhaust package and I need to know where to start with jetting. My shee is bone stock, and I am going to drill two 1" holes in the back area of the airbox lid and put in 1" uni filtered vents. Air filter is stock for now. I live and ride at elevations from 1600 ft minimum to 2500 ft maximum. I am in northeast Tennessee, so it is warm here. I have a sets of 280, 290, and 300 mains to try. Should any of these be close? I have jetted before, but the shee is new to me. Do I have to remove the carb completely to have room to get to the main jets, or can I loosen the hose on both ends and twist the carb enough to get the bowl off? Thanks in advance for your advice. Man, I cant wait to get these pipes! :thanks:

 

its much easier to take the carbs off. you can make sure your floats are set right at the same time and clean everything out. whatever you are running now, bump it up 8 and that should give you a ball park. Do a plug chop and dial it in from there. example of 8,... 220 to 300,.... 200 to 280. Its always good to start rich than lean.

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its much easier to take the carbs off. you can make sure your floats are set right at the same time and clean everything out. whatever you are running now, bump it up 8 and that should give you a ball park. Do a plug chop and dial it in from there. example of 8,... 220 to 300,.... 200 to 280. Its always good to start rich than lean.

 

Thanks, fastrthnu. I have never disassembled these carbs before. I wont need to open the tops of the carbs until I get into changing the needle clip position (if it is needed). Is removing the lower (float bowls) on the carbs all I will need to do to change the main jets?

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If your Meticulous and Precise at what you do just like ME i would take the carbs off ....1 at a time........like (fastrthnu) said it's much easier and it gives you a chance to see what your carbs look like, gives you a chance to clean them, check floats, etc. I live right at sea level and i'm running 280 with double K&N Filters one off each carb with Toomey T5s with some more stuff. Given where your located i would try the 290.

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260 mains...and you'll be a little rich at the higher elevation (2500 ft. or so..)

Normally, removing the lid with pipes is 280 to 290 around here, 65 to 85 degrees....and 0 to 800 foot above sea level.

 

You're up higher, and you're leaving the lid on...so...leaner is going to be the ticket. 260 should be a safe starting point.

 

Then plug chop.

 

http://www.dfn.com/benkaren/plugchop.html

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The DMC website instructions suggest with a stock engine and vented lid (this is exactly what I will be running) to use 280 mains, needle clip in stock 3rd position, and 30 pilots. Doesnt 30 pilots seem a bit large? Most either seem to be running stock 25 or 27.5. Surely the aliens do not need 30 pilots to make idle to 1/8 rich enough?

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