YZ250 into 250X, all you need to know - Dirt Bike Build

Hey Guys, looks like we are ready to start YZ250 dirt bike build! In this video I am going to share my plan hot to turn Yamaha YZ250 into full 250x enduro race machine, we will talk about all the essentials for engine to get that X power delivery. Cheers!

things I use and recommend:

Yamaha Yz250 dirt bike build

[dahatchery]

Great vid! I own 2 YZ250, a 2000 and a 2002. Love both bikes. This isn’t the only way to do a trail build. I’ve had both my favorite bikes cylinders modified for a better low end power delivery through Eric Gore. He tuned the cylinders for a better more smooth power delivery. Yes gearing from a 250x most certainly is flawless but you don’t absolutely need it. I love my 2 YZ250s, trails are all I do. I’m 58 years old and the YZ is my absolute bike. I’ve been offered a KTM here and there and they most certainly have the luxury of an electric start, a plush suspension, and stuff that would make a dirt bike take to The moon! I really don’t need any of it. The YZ is my favorite. I own 7 dirt bikes. 3 YZ125s, 2 YZ250s, an 03 RM250 trail modded, and a 03 CR500AF from an 03 blow to crap CRF450! All bikes are 2 strokes because when you really do know the science, for all around riding and not ALL racing the 2 stroke will take you very far from home with an absolute reliability, so long you know your bike and the maintenance of it. The Euro bikes are fantastic, I find them to make me lazy. I don’t want one.

[PremixandPedals]

That is going to be a cool build! Being the old school guy I am, I say that if you want the ultimate two stroke trail bike just find a an early 80s IT!

[scottmeredith]

Man this will be a great build. Thanks for the shout out my friend!

[EarthSurferUSA]

The lower rpm pipe, that I don't see here, will probably gain more lower rpm power than all the other engine mods combined. Porting and pipe are the 2 biggest factors in power generation, especially if they are matched up well (port and pipe peak power rpm target.).

[theblishknovk]

I just got a yz125x and absolutely loving it. I was originally hunting for a 250x. I stoll want to try the X to compare. Im afraid i will want both for different reasons. I dont know if i will ever get rid of the 125 though. New found love and fun on the small bore.

[tomnekuda]

This build sounds like what I did in the early had a YZ 465 that was in perfect was that on the rough, tight trails it was killing me with too instant power and suspension. I answered an ad in the newspaper for a used 465 IT. When I got there I found it to be in good shape(blown clutch) and bought for $300. I swapped engines/trans, the shock and forks when I needed to use it on the tight/slow going. With the wide-ratio trans and IT barrel/pipe it was tamed considerably and made a really good compromise. I also took head to machinist to tame the IT even more and make it less picky for gas quality. By swapping parts I could virtually make the YZ anything I wanted it to time and effort. I used White Bros longer clutch arm to ease the pull at the lever. Hang in there. Too bad they don't still make the big 2-strokes both enduro and YZ.

[EarthSurferUSA]

I did not find the stock YZ250 to have hared hitting power. Soft on the bottom, almost OK in the mid-range, then smooth but pretty good acceleration to the top in an effort to keep up with a 450 on a MX track. It was probably the smoothest (and maybe the slowest), 250 MX bike I ever owned, but I fixed that. Try a 97 KX250. :)

[boonedawg]

I just saw this video and thank you. It didn't even cross my mind you could swap powervalves and turn the 250 into an X.

[brianmorrison]

I have the 250x. The squish with a oem top end was about .110" so I think you would be better off having the yz head redesigned with a more appropriate squish clearance.

[DRockDreamin]

Just picked up an 02 YZ250 and was looking to do this setup! Looking forward to it

[TM-lwwn]

yeh, thats a good idea, take a great bike and de-tune it into a less powerful bike, give it a transmission that makes it harder to stay on the pipe and a clutch that slips, awesome.

[newtonh]

Hello there Love your Channel much and this is my best bike build yet coz I had the same issues few years back were I had bought a 2015 YZ-250 and Built a it up to a Enduro Race bike...I did it coz I was Not riding MX and Loved Enduro riding and Yamaha bikes💪😎 I have Raced YZ all my life growing up so that's Y sticking to YZ and not KTM or such bike that's already Enduro bike. But coming back to the point... You still need A Very Important part in this build and that's n "Weighded Flywheel" ... This is to Cary the Torque through at low Rmp's especially on the Technical climb sections...al was done om my YZ to be the X but I didn't do the flywheel and boy did I Struggle a lot on the Rocky Climbing sections! The bike kept on stalling🙈🙉 Ow and also get Radiator Guards and Electric fans it's a Big Must have!! hope this info helps a bit to get that done as well... Keep up the builds its Awesome 😁👌🏻✊🏻

[Legion]

Awesome stuff, considering doing this to my YZ250

[usualsuspect]

Love the new intro rado! This will be a cool build!

[endurol]

I’m in the Uk we only got 150 250x’s re-named to Wr250x along with other parts of Europe for 2016 only. I have 1 I love it.
I have V force 4 reed cage & fmf gnarly atm, can’t decide between the turbine 2.1 or power core 2.1 end can.
The gnarly I couldn’t feel too mad of a difference but the V force made a difference in bottom end response & pull and better hit in the band. I’m thinking to import a rk tek head next & also putting lectron on. Looking forward to seeing your bike develop

[danielplace]

The cylinder is different too on a X model.

[mikewatkins]

Just install the power valve governor spring out of a yz250x before anything else. $8 from Yamaha and it totally changed the power delivery of the engine. It may be all you want to do

[kirkthepimp]

Sxs makes awesome skid plate for off road

[Marvelfunfaqs]

Nice project Rado, this is going to be a great build.

[fishtailfuture]

Hey I was hoping you had those part numbers handy so I can make sure I get everything ordered. Especially what I need for the power valve adjustment.