TRX250R.ORG
Workshop => Carburetor, Intake, and Exhaust => Topic started by: Red89 on February 24, 2018, 01:07:05 AM
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Alright guys I need some insight again. I have a CT310 bored at 73mm with a basic clean up port job, a 36mm carb, and a K&N filter with no airbox lid. I will be running 100 octane with 32:1 klotz super techniplate. Where should I start at on the jetting? It currently has a 40 pilot/slow jet with a 150 main and needle in center position (was at very top of needle). I believe that with those jets it would be too lean. Thanks in advance
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That's lean. On my drag ported esr 310, I ended up with a 175 main if I remember right, 52 poilet, and clip in the middle slot. This was in a 39mm carb and it was still a tad rich.
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So mine being a 36mm I should start around 175 and a 48 being I'm not ported just cleaned up
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If I were you I'd start with Atleast a 52 and if need be work you way down. Someone can correct me, but I think most bigbores prefer a 52-55 poilet.
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I'm not sure if you seen this or not but this has been really helpful for me.
https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.duncanracing.com/TechCenter/KeihinCarbJetting.pdf&ved=2ahUKEwiEw52xsb_ZAhVJz2MKHSvfAyEQFjAAegQIBRAB&usg=AOvVaw0X3yt0-Vo5HcvLUzZzQ4Xw
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Elevation? Temperature? My 310 stroker is jetted at sea level with a 52 pilot and 185 main. Needle center groove. I would recommend a 50 pilot and 180 main to start. You will probably work your way down. A lean pilot isn't that big of a deal. Loren
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Thanks guys! I will use a 50 pilot and the biggest main I have is a 172 for now, so I will see how well that does. I'm in Kansas so I'm about 2000-4000 above sea level. And weather, well it's Kansas so all over the place!
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Just be sure to go easy on it until you know for sure the 172 isn't too lean.