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How easy to make a WR250F(Or 250x) into a YZ250f (Or CRF250F)?

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I am thinking about buying a crf250x (or wr250f) and turning it into a crf250r (or yz250f) or at least as much as I can within reason.  I mainly ride tracks, and i would much prefer to have the motocross version of these two bikes, but I live in california and don't want the red sticker and give up being able to ride at two parks that are within an hour of where I live and follow the green sticker/red sticker deal.  (Yes I know you can still ride at tracks year round, which I ride at as well, but my fiance who just started riding prefers going to the OHV parks). I don't race and I'm definately a novice level rider on the motocross track, so I dont need the latest and greatest motocross machine.  I had a 2006 yz250f a couple of years ago before I sold all my bikes because of bills to pay and I loved that bike.  Felt waaay lighter, faster, and handled better than my friends stock 2003 wr250f.  

 

So if I bought either a crf250x or wr250f  I would send the suspension off to get revalved and stiffened up for motocross riding (and maybe shortened an inch or two because I like the feel of pit bike/smaller bikes) and I would also take off the lights and possibly the e-start in order to shave off as much weight as possible. I was also planning on switching the gas tank,seat, and plastics over to the motocross versions to give the bikes a more slim feel and reduce weight some more.  Also was planning on doing some minor motor mods such as aftermarket exhaust, cam, etc and  anything else thats not too expensive but would make the motor compariable to the 250R (or 250f).  

 

My question is, how easy (and expensive) is it to turn the WR250F into the YZ250F?  How close can you get the WR to feel like the YZ? (both motor wise and suspension/weight/handling wise?).  Obviously the WR will never be like the the newer EFI YZ's, but if I could get the WR to feel close enough to an older YZ (2006-2009 for example) I would be satisfied.  

 

What mods do you think would be absolutely essential for doing this conversion?  Whats the approx. cost for these mods?  Also do you think its worth the money to switch the rear wheel to a 19" vs the stock 18" for motocross riding?  Or does it not make that much of a difference? 

 

What bike would be easier to convert to its motocross version?? The WR250F or CRF250X?

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A waste of money, and you'd prob be diss appointee with how it turns out. Just buy an older mx bike if you're short of $$. You still may need to do suspension upgrades and minor engine works. But you won't have the hassle of all that work for a shitty result.

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A waste of money, and you'd prob be diss appointee with how it turns out. Just buy an older mx bike if you're short of $$. You still may need to do suspension upgrades and minor engine works. But you won't have the hassle of all that work for a shitty result.

 

Sounds more like a California Issue then a money issue from what he said about stickers. I know nothing about California laws so I dont know what that means exactly, lol.

 

And OP, the trans would still be the WR trans. Which may not be the end of the world for a lot of people. Believe it has a heavier flywheel also.

Edited by J_YZ2fittyF

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A waste of money, and you'd prob be diss appointee with how it turns out. Just buy an older mx bike if you're short of $$. You still may need to do suspension upgrades and minor engine works. But you won't have the hassle of all that work for a shitty result.

 

 

Sounds more like a California Issue then a money issue from what he said about stickers. I know nothing about California laws so I dont know what that means exactly, lol.

Ya its not a money issue just one of the joys of living in california  :banghead:   For those not familiar with red sticker green sticker law in california, it basically makes it so you can't ride any motocross bikes (like the yz or 250r) during the summer months like may-october on trails or OHV parks.  But the wr and 250x are ok to ride year round. Private mx tracks you can ride year around on any bike you want which is why if all you ride is track its not a big deal, but I like doing both (especially since my fiance will only go trail riding).  

 

I understand my conversion bike will still not perform as well as a true motocross bike liek the yz or 250r, but I dont race so I dont need the best of the best and I'm a pretty slow inexperienced rider but still love track riding more than anything else, so basically a lot of the little details of a bike that a more experience rider would notice I probably wouldnt be able to tell.  Because of this, I dont need a perfect conversion bike, just somethign close enough.  I have thought about buying a yz250f or crf250r motor on ebay and then dropping it into a wr250f or crf250x chassis because from the DMV's point of view, the vin number on the frame is the only thing that matter when it comes to red sticker/green sticker.  

 

Actually I think I just found the solution to my issue!!  I could buy a complete yz250f or crf250r and then buy just the frame of a crf250x or wr250f that comes with dmv paperwork on ebay and swap the parts over !!  This should work fine ya???!!

Edited by punkguitarist

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I dont know that you need to get a diff motor. I mean the heavier flywheel just causes it to rev a little slower then a YZ, but also allows it to be lugged better at low rpm (to help prevent stalling in tight woods). You could just forget messing with that initially since you will ride trails too and just see if it bugs you on the track (if you really even notice it). If you find you want a lighter flywheel, you could try and trade someone who has a yz and wants a heavier one because they trail ride it. The trans IMO would be too much work/$ to be worth changing. I wonder how big of a deal itd be for a lot of riders, I doubt itd bother me all that much. Plus again itd be nice for trails.

 

The 18" is going to be heavier...so if you want to lose weight, you may want to get the 19". However, how much of a difference and how noticeable it will be, again may be worth just trying the 18 first and if you dont like it...sell it or try to trade once again.

 

Other then that, ditching the lights and stuff like you said. The suspension would need to be done as you also said you were going to do. I tried jumping the wr i had one time, wow...i only did it ONE time, lol. Really thatd probably be the biggest must do if you plan to ride a lot of MX with it. Lastly, I wouldnt spend tons on one area if it means only a small weight reduction in that area. People put all this concern into the weight of their bike when A) they arent even that fast, B) they are overweight themselves, and C) they lack the skills to actually be fast enough for a small weight difference to reaaaally matter.  So a bike that weighs 3lbs more doesnt mean jack crap to MOST riders who are honest with themselves (dont mean to offend anyone, but you know its true). I know I could lose a lil myself...so not preaching like im super fast and ripped up...cuz I am neither, haha.

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"I am thinking about buyingicon1.png a crf250x (or wr250f) and turning it into a crf250r (or yz250f)"

If you want the wrenching experience, the go ahead.

If you want an MX bike, buy an MX bike

If you want an enduro bike, by an enduro bike

if you want a street bike, buy a street bike....

Anything else is just turning a silk purse into a sow's ear.

:banghead:

 

I have put a WR tranny into a YZ, and it does well for certain tasks, others, not so well.

 

Edited by ronbuell

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I have both the 07 WR with a bunch of mods and also the 12 YZ250F. I've been around the WRs since they came out and have also owned a 05 WR250F. OK, so you want the 07 WR or newer. Same weight as the older ones, but the alum frame feels 20 lbs lighter and handle better. Also, the 04 and older have funky transmission ratios and you don't want that. 07 and newer have better gear spacings, although don't go as fast on top end.

Ok, so first part of your question on the power... You can get a WR to pull pretty good. Not quite like a YZF, but pretty close. The mods you would want to do will be- get rid of the air injection to lose the lbs, block off the air cut valve and rejet pilot air jet. I switched to a HotCam Stg 1 intake cam and a YZF OEM exhaust cam- this combination gives the bike better mid range than with a HotCam exhaust cam. Use HotCam exh cam for more top end power. Switching to the 08 OEM piston would be a good addition as well, and perhaps with that higher compression piston, the HotCam exh cam would be a good choice.

Suspension... I have the Smart Performance Stage 4 kit. It works good. The WR shock is valved light (no surprise) and the fork is just lame. Add the kits and you'll be jamming.

Weight... The steel rear sprocket can switch to alum, toss one of the rim locks, headlight and odometer are lbs, switch to a lightweight battery, and you could remove the sidestand. Maybe pull the kickstarter if you are confident in the e-button. Be sure to keep all the stock parts for resale. All told, I think you could drop 15 lbs or so off the WR.

The cost to modify will depend on how much you do yourself.

Good luck with it.

Edited by BazookaJoe

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Sounds to me you're thinking out loud.

What I'd do:

 

If the No. 1 thing is to use one legal bike to ride both state-owned OHV parks and privately-owned MX tracks, well, I guess you need a legal bike for the OHV parks.

Get yourself a 2007-or-later WR-250F (as they are all the same except for colors and decals), uncork it, tailor the suspension to your liking, and ride the bike and maintain the bike.

 

To me, it is better than making it into an expensive science project when you're a novice dirt bike rider.

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In my state of Victoria, in Australia, we have two kinds of motorcycle registration. Full rego, and Recreational rego. Full rego means you can ride any roads nationally.

Rec rego means you can only ride non-arterial roads out of built up areas (basically back roads and forest roads/trails), but you are still covered by the compulsory insurance included in the registration.

Anyway... I bought a YZ250f and did the conversion to get it Rec registered. So I installed an after market led lighting kit.(headlight, tail light, and brake light, switched from the rear brake, and horn.

So I converted a track bike to a trail bike. A pain, but well worth it. Only thing I wish I had is elec start. But I would not convert a road-trail to mx bike.

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First of all if its red leave it in the shed! they are plagued by valve wear "problems".

 

Second, i also live in CA and can appreciate a Green Sticker. Buy a YZ, then buy a WR frame (you'll need the title, swap everything over the WR frame (06+ only!) and that's the way you do it. Everything fits.

 

In reality though, you do NOT *need* to have the lightest or meanest machine if you're only a novice rider. What you do need is suspension able to handle the MX track, and the WR doesnt have it. You can, however, put the YZ suspension on the WR. I'd still go the way of buying a YZ and a WR frame.

 

Where in CA are you? I ride Carnegie, Metcalf and Hollister quite a bit.

Edited by etxxz

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Maybe I should define what I mean by a novice rider. By novice rider I mean I ride during the "vet/novice" practice at the local motocross track instead of "a/pro riders"" practice but I can still clear the 80-100ft tabletops at the track and do every jump, but I am still not a fast rider compared to a lot of the riders at the local track. I can do all of the "black diamond" trails at the places I ride at, but still I don't consider myself fast at all and I don't race or have any plans to so to me it's more important to have a green sticker bike then to have the latest 2014 efi 250f

Motocross bike (although it would be nice!!). But I have had a old 2002 yz250f green sticker

Bike but compared to the newer aluminum frame bikes, I hated it. So I definately want aluminum frame which is why I am considering doing the wr frame swap

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