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Discussion Starter · #1 ·
Ok so this yfz450 is new to me and when I got it she didn't run. Found the problem was out of spec valves. Fixed that got it running but it has bottom end stumble. It's fine if you slowly get on the gas but you can't stab the gas without it stumbling.. Jets in the carb are 175 main, 48 pilot, and 90 starter. Did look like the pilot was a little clogged so that may have something to do with it. Also seems to idle high and doesn't really change to much unless you back the idle screw down allot... Lastly being this ATV is new to me all I know is it has hmf full exhaust, no air box lid, kibble white springs,( saw this from adjusting the valves), and was told kibble white upgraded valves but can't verify this, and cams but I can't tell if they are stock or not. Now I noticed when I pulled the carb that the head might be ported but I really don't know how it looks stock so I took a couple pics for you guys to see..


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