February 2, 201313 yr Hi, just wonder what would give the best running. Bike - Sherco 2009 290 Pilot Jet - 35 Main Jet - 122 (Use to be 33, 118)
February 3, 201313 yr The question itself is too general. Things do vary a bit carb to carb and bike to bike, then you add dirrerent fuels, and then personal prefs and expectations. Then throw in cold or hot temps and such. Long story made short, if it runs fine at your current settings and you are able to set the fuel trim screw to a decent response, then you do not have a problem. I can tell you you are in the window it seems, now if you have a problem say revving out cleanly and quickly, you may want to go back to the 118 main jet. Call Splatshop Chris for further generalities!
February 3, 201313 yr Author Thanks for the help! Bike runs and idles fine. Just wondering if 35 122 was rich for my height and what others ran at a similar height. Can someone explain what a rich bog is? If the standard is 33 120 for seal-level should i not really go down in numbers as there's less air
February 3, 201313 yr A rich bog is where Richard Branson dumps...................... Colder air is denser , more oxygen, leaner mixture. Your right altitude means thinner air. If your bike feels like the choke is on its too rich, if you open the throttle and it makes induction noise but loses power this is usually over lean, in this case putting the choke on makes it better. Jetting is a dark art, and nigh on impossible to over the internet.
February 4, 201313 yr Your altitude above sea level is a non factor really. The temps and baro effect more change than your altitude where you are. If you want to see these changes, plug your numbers into a "density altitude calculator" google it!
February 4, 201313 yr If the standard is 33 120 for seal-level should i not really go down in numbers as there's less air? All the bikes come lean from the factory.
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