Boyesen Rad Valve jetting suggestion for 06

Ok little background: back a month ago I picked up and 06 YZ250 that is show room quality...maybe 1-2 hours on it...$2900....wanted it specifically for the Idaho sand dunes which are 15mi from the house....have had it on the sand twice with the pirelli sand tire and run the guts out of it....I love it:thumbsup: .

I'm running 32:1 with a mix of 2/3 93 pump gas and 1/3 cool blue 100 octane pinging.....plug is dark brown...and it is pretty crips eveywhere...stock pipe with factory sound 304 PC..otherwise stock.

So I plan to slap the Rad valve on this Fri...and go to the be safe how far above the 175 main jet should I go to start with???? will the 4st jets that fit my O7ktm 450xcw work in the carb on the YZ?

I know there have been posts on here about fellow riders having to play around to get the jetting right after the addition of the rad valve and I'm hoping one of you experts can give me some guidance.....Thanks in advance

well i would see how the current main you have will run with the cage. On my vforce 3 setup i didnt have to go up on jetting even though on paper the jetting is supposed to change since the motor is getting more fuel. As far as ktm jets go, they will not fit.

i would say u should be able to leave ur jetting and still be safe because boyesen recommends leaning the main size down 1-3 settings. so i would say for the dunes you sould be fine with ur jetting and then be able to slowly lean it down.

Ok, thanks Rusky and Paul-p....I'll take it easy for 10min and then read the plug with my current jeting...just don't want to burn down my new toy right of the bat...rad valve is in the mail so I had no idea about their recomendation....good to know about the jets too...will pick up few from the yami dealer.

where this may be headed is a 265 or 285 kit...but I'm so stoked to have a great 2stroke more blowing up 4t on the dunes for me....last two stroke was 01 ktm 380sx..7 years of a 4t diet only.....this 06 yami handles so damn good its sick...I can rail thru deep sand whoops faster and in better control than my 04 or 05 CRF450.....had no idea they handled this good.


i have the 07 with radvalve and i stayed with the same mainjet as before i did have to go to a 45 pilot jet and also dropped the needle i clip .my set up now is main 185,45 pilot,n3ew needle clip position two down from top, air screw 2.5 turns out ( my 07 is europe spec bike ) i am in thailand at sea level. the radvalve gives a real boost over stock set up ,the jetting took some time to sort out as i followed the boyesen info?. the radvalve is worth the time and effort to get right. philly cee

I have found you decrease the jetting with the RAD valve as the literatuure suggests. The Rad Valve flows more air; Hence the leaner jetting is required to get very good over reve and top end. It will run fine with the stock jetting but you will be giving up some performance. I have a JD kit with the RAD valve and in combinaton I use a 165 main at 500ft, 80 degrees, 32:1. If I recall the JD kit says to use a 172-175 main.

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