ohio jetting with yz450 cam

Just curious where to go with jetting after doing the mod. here is where i am at now. 2002 wr426, yz pipe, airbox lid off, throttle stop cut.

obdrr needle #6 from top

180 main jet

42 pilot jet

65 starter jet

75 pilot air jet

200 main air jet

pilot screw 2-1/4 turns out

This thing was a real rocket before the mod, I think now I need some jetting work to get that back, I have read for hours the posts on jetting but very few from ohio. Altitude is 500 to 800 feet and temps about 55-65 but warming soon. I will do the BK mod tomorrow while carb is off. Any help would be greatly appreciated. Thank you, Dan

I am not sure what mods you have but a 160 main and stock YZ needle in clip 4 should be a better starting point to work from. Your current jetting is way richer than I have heard of on this forum. I hope this helps :)

I have a stock yz needle (I think obejp) and also have a good assortment of main jets. I will try that today after doing the bk mod. I have done no other mods except for what is in 1st. post. Thanks for the reply, I will report back. Dan

Hey cheif what part of ohio are you from ? I live in southern ohio maybe we can hook up and ride sometime. As for your jetting the 180 main is to rich i tryed everything from a 160 to a 180 and settled on a 170 anything leaner than a 170 felt like it lost some of the topend pull.Ihave a 45 pilot jet in mine,you show that your fuel screw is 2 1/4 turns out if you had to turn it out that far to get it to run good then your pilot's to leanyou shouldn't have to go over 2 turn's out.Mine is about 1 1/2 out.Try a 170main and 45 pilot get the bk mod dialed in and you may have to change your needle clip position a notch or 2 i have a different needle than you so i can't help you there,i have a stock needle clip 4th from top.Do some experimenting and let me know what you come up with.

Thanks evil, I'm working on this thing today so I will experiment with those settings. I thought I was too rich but the plug still looked kind of white. I'm going to start over w/new plug and see what happens. BTW I live north of marion about 15 min. and ride out of camp ohio (wayne national forest) whenever time allows. I will keep everyone posted. This place rules :)

Hey chief240,

I hear the wayne national forest has some awesome trails. Let us know if it is worth the drive from Indiana. I hope the jetting goes well. We are about the same elevation and temps. Thanks :)

Yes Indy, Wayne has some pretty good trails. We dont ride them alot because of those crazy quad riders coming at you the other way. We opt for the old single track where they cant go. Just about every time it requires GPS to get us back to the truck, lots of briars and nasty hills. I think you would not be dissapointed with the trip. It would be better if you had someone to show you around though, It seems like I get lost every time. As for the jetting I've got it pretty close. I'm at a 170 main, 50 pilot(thats all I had 45 on order) screw about 1/2 turn out everything else the same. I think the bk mod made the biggest difference. While I was at it I disconnected the blue and grey wires. Now I need more time to test. Thanks to all for the help. Dan :)

You must have the pipe uncorked completely to be on the 170 main. I use a baja baffle. Thanks for the info on Wayne county. :)

I am running a stock yz pipe and btw have you ever ridden at haspin acres??

Haspin has some great woods trails away from the main parking lot races and motocross race track. Most people do not venture back there so it is OK on crowded weekends. I dont like it when it is wet because the clay makes everything like a skating rink. The parking lot is a zoo. Crowded with a lot of stunting going on. I prefer the Daniel Boone Forest in Kentucky. That is my favorite place to ride. It has everything. I may try bumping up to a 160 main this weekend and see how she pulls. Thanks for the reply. :)

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