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09 YZ450 jdkit

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New to this forum, thought I would share my personal problems.

Use to race MX in junior high and high school KX125, got older and went to sport bike, fazed out of the dirt world.

12 years later. Got a yama450f afew months ago, always want a YZ haven't rode anything four stroke since the glory years and go big or go home.

Holy crap I have missed out on a lot, playing catch up but having a blast with this power house. Already entering in local HS and moving up the class's.


I am getting back into carb work, friend sold me a used R@D power bowl ( after install found the biggest advantage was the heavier spring for the Apump lag) but brought the bike to life on the trails. 

 Got the JD jetting kit and found that their o-ring method does the same thing for a fraction of the cost.

My question is with the JDkit they rec a 170 and clip at 5. the bike is all stock 160 with clip at 3pos.

Im at 900ft Kansas City MO is JDkit settings acurrate for an all stock setup? and what would you rec for a all stock setup. Bike seems to run lean and hot now. Im just lazy I guess, I know most you vets are gonna tell me to try one jet then another and I will. Just want to get a good known and go from there. 


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The YZ's are harder to jet perfectly than other bikes with the FCR carb. It's because of the restricted head flow.

The JD Red needle and the 170 main should be fine.

As in the cylinder head flow or the exhaust headers, i read that the muffler has a good amount of restriction. This bike is enough for me at the moment the exhaust and pipe will happen sooner or later. I see you have had many yamahas and although port and polish is alittle far out from my performance demands, just going for a well maintained/running/clean trail bike. I may have to whore you out for info as this new additiction continues :rolleyes:  if that ok with you.

Thanks. jets will be in this weekend and rekluse is on order, keep updated to my offical outcome.

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