1991 Yammaha WR 250

[vignale]

I have just bought this bike. Starts and runs well. The shock (under the seat) seems to be soft. The sprocket is badly worn and will need another. And I guess I should do the chain also.

Want to do a rad flush, any tips? Can you also point me towards some place where I can get the info on the bike and maybe some good pictures???

Thanks for everything!

 

[cruzin925]

http://www.off-road.com/dirtbike/

check this site.. i know there is alot of cool stuff to check out. I'm pretty sure somewhere there are a whole bunch of reviews on old school moto's, hope this helps ya out mate ;)

 

[fuzzy]

Great bike. Same as that year YZ except it has a Flywheel weight, lighting coil, large gas tank, Wide Ratio trans, slightly softer sock spring, and a round slide carb.

 

[fuzzy]

http://www.yamahaoftroy.com

 

[motometal]

If I recall correctly those bikes had a great motor...way fast!

 

[fuzzy]

Yep! The motor makes the WR. It almost makes me feel sorry when I see the $5.5k 4 strokes out on the trail. It seems that the 2-stroke WR's were kind of rare/low selling. It is one of the few japanese 250 EXC equivilant's. The WR, and the RMX are about all I can think of. KDX's are in a class all my themselves, IMO. It is a great enduro/hare scramble bike and makes a pretty good MX play bike. Mine makes phenominal power from below idle to hard overrev. Very similar power to the current model KTM 250 EXC, but with a stronger, less controllable midrange(I am playing with jetting to cure this). Mine will pull even with my buddies 99 250 EXC until mid-top where I will take the Katoom. It WILL scare an inexperienced rider. I prefer it to a new KTM due to it's small chassis. It's about the same size as my 93 KDX!! Great in the woods, just watch the right hand. I call it my "Budget EXC"

Your older gen WR motor is supposedly the same as mentioned above with even more of a midrange power surge. I'm looking to port mine and add FWW to help make more electric power also....

Enjoy it!

 

[MilkJuGGz]

Ok, so why did the WR come with a round-slide carb compared to the YZ's of the time?

 

[fuzzy]

You've got me?! The Mikuni VM is a POS of a bike carb IMO! I swapped mine out for a YZ carb of that era (Mikuni TM Flat-slide). I think the round slide may have been used to help with power delivery. Some riders complained that the power was uncontrollable in the woods. By switching to a RS carb the crappier throttle response may have been an attempt to cure this. All this carb did was make the motor a plug fouler. Mine never fouls plugs, and has great throttle response w/ the TM.

I love the power delivery this engine provides. You have to watch the right hand, but I've never ridden a (modern) 250 where this wasn't the case! I'd have to say riders that experienced problems w/ power dilivery weren't used to a wide ratio trans.

In short, my opinion (and that of many other WR riders) is that the VM carb was a mistake...

 

[jmics19067]

wild guess on the round slide is probably helping to clear out the old stock at the factory plus you get that neat little rubber boot over top or the throttle cable/ carberator junction for off road :confused:

there is a slight difference between the rubber manifolds between my 94 wr and my 94 yz,< I bought both bikes used but I believe that they are original pieces> the wr has a reed cage stuffer which should help part throttle/lugging type of situation. Also the WR rubber manifold does not match up perfectly to the flat side carb, small issue of where that little sealing ring mates up to the notch in the carb. probably nothing too serious but something that yamaha didnt want to leave to chance.

My take is those generations of WR where not a true serious effort for an offroad bike like a kdx. The KDX was a bike designed for its purpose , but the wr was more of a lets try and build a competetive MXer and as kind of an afterthough let see what we have lying around the factory that will fit on this bike to make a different model. After all even though they added a lighting coil they didnt bother to make a headlamp or tail lamp for it, 18" rear wheel when the motocross world was starting to go to 19" , older intake systems ,and no different engine or exhaust system changes<spark arrestor was your problem>.

So basicly what they had was a bike for sale to get the market of the people buying MX bikes and either converting them to play bikes or offroad racers. It was cheaper to buy a WR then it would have been to buy a CR or KX and then add a lighting coil , 18 "rear wheel and a large fuel tank. They had the XR and KDX that they would of rather of seen in that genre. And a lot cheaper if you raced motocross and enduros then buying two different bikes.

 

[fuzzy]

Yeah, what a gip on the lights/spark arrestor!! Good note on the intake! I noticed the TM fit a little wierd.

Kinda cool you own both a 94 YZ and WR. FYI...In 94 Yama did change the powervalve on the WR motor. I know some YZers switched to this powervalve to tame the midrange a tad.

 

[jmics19067]

I believe this too be true of the 94 powervalve. I thought that the wr and the yz are the same < both of mine are the same>. Earlier powervalve governors slow the opening and later powervalves had a different design to bleed off the midrange hit.. With say a 95 yz being a better offroad engine and the 94 wr being a better motocross engine<?>


I like my 94 yz but it is getting old so I was always looking for used/spare parts etc... I came across a 94 wr that was complete and registered so impulse told me to buy it :o I have completely gone thru the yz so it is basicly two year old stone stock and now going thru the wr making it a dual sport... almost. something I can connect trails with and if I ever get lost in the woods I can ride the street back to the truck with a minimum of fuss hopefully.

I eventually plan to try a lot of different ideas/testing of different things on the YZ and if the event of a catastophic failure creating problems trying to solve problems :eek: I will still have a bike to ride. Having 2 similar bikes should make it a lot easier to see if things I test actually work . I have a strange fascination with "tinkering" being more of a dedication than my actual riding capabilities.


ehhhh it keeps me out of the gin mills

 

[fuzzy]

ehhhh it keeps me out of the gin mills

LOL!! You're right there! Although sometimes it put's me in them!

The 93-95 YZ's had the same "4-ball" powervalve governor's as the previous gen YZ/WR's. The 94-97 WR had a different "5-ball" powervalve governor that I believe was unique to the WR engine in it's dying gen.....Have you compared the powervalve governors on both your bikes by chance?

Sorry to see them go....I'd buy a '03 WR250 Two-stroke in a hearbeat. Looks like I'll be riding a pumpkin in the near future. I could modify a YZ for trail use, but these thing never work out unless you're building a HS monster--never end up w/ a wide ratio trans. I will never get rid of my 94 WR!

Can you tell what I think about 4-strokes? :)

 

[jmics19067]

I never went into the bottom end of the wr ......yet. heh when I bought the bike evrything felt good shifting and such and when I did the top end of it the rod and crank appears to be in good condition. So even though I do create a lot of work for myself I felt it was unnesecary to go that far into the wr. As I said before yet..... ;) maybe I will take of the clutch covers off this weekend and have a looksee.

I loved my wr 400 even though it took me forever and day to figure out how to ride it . Being mostly a trail rider with a few d class motocross races , once I figured out to not touch the rear brake or the clutch for turns it was an absolute pleasure to ride the trails. front brake and engine braking to slow down before the turn and then smooth acceleration thru the turn. Used to give my 2 stroke buddies fits on single track since I would be slowing down way before they needed to holding them up and yet I could get out of the corner faster that way then thay could. It sounded kinda cool also me 3 rd gear bwwwooooooooohhhhh ,,,,,,,,, whooaaaaahhhhhh him 2nd brap 3rd brap 4 brap then his squeaky brakes .If it never was stolen I doubt I ever would of gotten the 94's even though having the two bikes definately suits my "let's see what this little gizmo will do " curiousity better


One thing you should never do is try and use the compresion release as an engine brake like on a truck. It hammers up the top of the cam follower and then scores up the bore in the head where it rides. Know that one from expereince :eek:

I have seen in these forums a discusion about the 4 stroke gear sets being able to fit in the 2 strokes. Not sure what fits what and how but who knows maybe an expensive<buy the 2 stroke yz and the gears from a wr> new wide ratio 2 stroke can be had from yamaha.


some day one of my aspirations would be to get guys like you and Splatt<he has a 94 yz with forward motion bigbore > down at like Dirt Week or something and play around with product testing. I have quite a few different aftermarket bolt on stuff for these bikes but unfortuntaely no time to test this year. I would need a weeks vacation and a moto oriented atmosphere to do what I would like and I figure the more bikes for a control and more test riders familar with the bike would give my personal shootout a better chance of credibility. As it sets now I change a pipe during the week, jet close Sunday morning if I can get out <which I havent been able to yet this year> then ride all day. I lose my back to back comparison , hardly an accurate shootout.

 

[Lissa]

Hey Fuzzy, you can install the WR 400/426 wide ratio trans into the current YZ 250 motor. Rob

 

[fuzzy]

Thanks Rob....That's some good info!

 

[placelast]

Originally posted by Lissa
Hey Fuzzy, you can install the WR 400/426 wide ratio trans into the current YZ 250 motor. Rob

..have heard that, but some grinding required to reduce width.

have seen in these forums a discusion about the 4 stroke gear sets being able to fit in the 2 strokes. Not sure what fits what and how but who knows maybe an expensive<buy the 2 stroke yz and the gears from a wr> new wide ratio 2 stroke can be had from yamaha.

Suzuki off-road team switches RM/DRZ gears around. Keid and Smith like RM trans in their DRZs, whilst Hatch stays stock.