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Yz490 jetting

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I have a 1990 YZ490 that I've owned for about 5 years. I have just recently started to tinker with it. I'm using the carb that it came with which is a 38mm PJ. I've been trying to jet and can't get it tuned in. Does anybody have any baseline jets to go with. Currently I'm running a 160 main and a 50 pilot and I'm not sure what position the needle is in. Im sure the bike should run stronger than what it does can anybody help 

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I'd find a factory manual and go off that to start out. Usually it'll tell you ask the factory settings and that should get you in the ballpark. How does the spark plug look? It should look chocolate brown on the tip.

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Yeah that may make things a little more difficult. I'd call a Keihin retailer and tell them what bike you've got, what the stock carb is and it's jetting, and what carb you currently have. To be totally honest with you, I don't like fiddling with carbs. I messed with the stock carb on my bike and got so sick of it I put it in a box and bought a Lectron. Best decision of my life so far. Sorry about the rant. But seriously though, call someone like Sudco or James Dean Jetting. They'll point you in the right direction. ;)

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