Looking to buy my first WR

Hey guys.  Snowmobile season in the Northwest was a bust and I'm getting the itch to ride!  I'm looking to buy my first bike and am looking for some advice.  Im looking at used 250r's and f's.  My main use will be Forrest roads and single track as i progress.  I'm looking for plated/street legal bikes for the Forrest roads here in WA.  I'll do a little pavement pounding but it will be minimal and around town for the most part.

Most in my price range ($2500-$4000) are 05-08's.

I keep going back and forth on an R or an F.  I'm short so the extra height on the F concerns me.  I have a line on a plated F right now and there are a couple R's around.

Any tips on which to go with and any major differences in those years?  I appreciate any input!

Howdy.

First thing to know when talking Yamaha WR250F versus WR250R:

The bikes are not the same machines, not engines or frames or suspension or even the front brake or clutch levers.
In fact, not even close, and it's only the way they both look like blue dirt bikes built by the Yamaha factory that has people wondering about any similarities.
So, it's imperative you remember to use and look for the letter on the end, be it F or R.
This tells the story.
For some reason (maybe to fool you), the Yamaha marketing men gave them similar designations, but, they are as different as can be.
Remember that.

The two models that are nearly identical are the WR250R and WR250X, with the differences being what makes one a dual-purpose bike and the other a motard, along with cosmetic differences (like frame and swingarm paint and fork tube anodizing).

I've owned a few of these bikes:
2008 WR250R
2008 WR250X
2009 WR250F
2002 WR250F (which I still have to this day).

Which one do you want?
The way I see it, if you want a dirt bike first and foremost, then a registered WR250F makes sense because I've had two of them, myself, and they are excellent dirt bikes.
They come with transmission and final drive ratios for off-road usage, so they are not a good choice for lots of street riding.
That means, unless you want to gear it up considerably (and hurt off-road performance), cruising speed is around 40 mph.
They are lighter and come with a better-performing suspension, and, are literally the off-road version of the YZ250F motocross bike.

If you were to ride the bike like I ride a dual-purpose bike (off-road after work or on Sunday, with road riding all week long), then the WR250R is the better choice, mainly because it has an extra transmission gear (6-speeds) and has the gearing to cruise at road speeds other vehicles cruise at these days.
The engine is also a bit smoother with noticeably less vibration.
This, along with the taller gearing for the street, makes the bike feel much better suited to road riding.
This is a big deal when you actually use the bike a lot on the street.
This bike is not the off-road version of the YZ250F motocross bike, but is made to look like one, especially at a distance or to the untrained eye.
That's the marketing at work.

Some of my other thoughts about WR250F vs. WR250R:

No matter which one you ride off-road, BOTH will require the same maintenance.
That is, both air filters will get dirty, even after one dusty ride off-road.
Both require engine oil changes on a regular basis, and the 3,000 mile interval shown in the WR250R Owner's Manual is for street riding.
Same goes for the 26,000 mile valve clearance check interval - if using the WR250R as a dirt bike, I'd check it at least once a year.
Heck, I'd check it once a year, regardless.
Both require periodic chassis bearing lube, lest they get rusty and squeaky.

WR250Rs are the same machine from day No. 1, so 2008 to 2015 model years are the same, save for cosmetics.

2005 and 2006 WR250Fs are practically the same, with the main difference being the 2005 model using the traditional mechanical trip meter and the 2006 model having the digital LCD speedometer/trip meter/computer.

2007 - 2013 WR250Fs are the same machine and mainly differ from the 2005 - 2006 models by using the aluminum frame based on the 2006 YZ250F.

By the way, I never felt any significant seat height difference between the WR250F and WR250R.

Just a question, Is the valve check interval the same on an F as it is on the R? When I bought my R in 08 they gave me a manual for a F/X, which made no sense. The valve check interval was 8000 miles which I did only to later find out that for my R it is actually 26000 miles.

The full designation of the 2008 WR250F was WR250FX, the X meaning 2008 model Yamaha motorcycle (a 2008 WR250R was WR250RX).
That last letter, which you don't always see in print or hear somebody talk about but is printed on the cover of the Owner's Manual, changes with every model year.
Some motorcycle dealers are notorious for not giving the buyer the Owner's Manual or handing the buyer the wrong Owner's Manual when taking delivery of their new motorcycle because the ones handling those books do not know the model designation methods used.
Been there.
Done that.

Practically all of the maintenance procedures shown in the WR250F Owner's Service Manual come much sooner than the ones shown in the WR250R Owner's Manual.
In fact, the maintenance schedule chart in the WR250F manual is a lot longer and covers more tasks than the one shown in the WR250R manual.
The WR250R maintenance schedule shown in it's Owner's Manual makes sense for a street bike.

Being that they are in fact different motors, does the design of the F motor require more frequent service intervals than the R motor?

I believe the intended usage is the main reason for the WR250F maintenance schedule being more active, not due to the design of the engine.
Racing is hard on equipment, and that's where the WR250F maintenance schedule comes from.

When I was 18 years old, I bought a brandy-mew 1983 Yamaha YZ-125K (for $1699 - try that today).
The excellent manual that came with that bike recommended disassembling the top end of the engine after riding it for about 20 minutes in order to inspect the piston skirt and sand down any high spots during the break-in.
Most guys, upon reading that, would either shirt a brick or laugh at the thought of doing that.