Yamaha WR250R Mega Thread

Discussion in 'Thumpers' started by Sock Monkey, Apr 7, 2008.

  1. jimmy2020

    jimmy2020 limpiador de ventanas

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    I am simply looking to put a set of offroad tires on X rims. I have an X in the States and the MT21's worked great. The 120's did have a little tire rub on the fork, but I trimmed some of the side tread.

    I'm in Costa Rica and tire selection is slim anyway, but even more with the X rims. I talked to a distributor today and he said he has the MT60 in stock and recommended them. Actually, I had never heard of this tire.
    I just wanted to see if anyone might be familiar and has tried these.

    I'm think my best bet is to see if this distributor can get hold of a pair of MT21's.
  2. Sewerat

    Sewerat Cert. bike whore

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    I ran the mt60 on a versys in the sizes mentioned. 160 rear. AWSOME tire for the street wet or dry. Reasonable on gravel roads. Useless in anything slick and muddy. Short wear life on the rear, approx 6-7000km and about 10-12 on front. I say short because same bike with heideneaus got almost double that on each end.
  3. Rapid Dog

    Rapid Dog bikes, booze, broads...

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    Your butt's gonna like you...SC seats are the Best Bang 4 The Buck...ever!
  4. Rapid Dog

    Rapid Dog bikes, booze, broads...

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    If your talkin' dirt tires 18/21 you don't need anything 120, let alone 130.
    A 120 in maybe some dirt tires, but a 110 will get you better results.
    Ask me how I know................but maybe you're talking 17" wheels....:ear
  5. Joe Watson

    Joe Watson Long timer

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    The latest ride with my WR250R. Out with a bunch of mates on the day of New Years Eve.

    <iframe width="960" height="720" src="http://www.youtube.com/embed/K5rwqMs-3GE" frameborder="0" allowfullscreen></iframe>
  6. sturgeon

    sturgeon Been here awhile

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    I recall reading something somewhere (either on thumpertalk or advrider, possibly in this thread) by the Yamalink guy. Sorry, wish I could remember exactly where. Some judicious Google work should find lots of info. I lowered my front 15mm, which is less than the rear is lowered, but that was just personal preference.
  7. ba_

    ba_ Long timer

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    Yeah there is definitely a lot of information out there. I was seeing if someone had a link to the definitive source.

    What did lowering by 15mm do for you?
  8. ramz

    ramz Professional Trail Rider

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    Yamaha designed the front and rear suspension to be in balance. The forks stroke in a 1:1 ratio: 1 inch of fork compression is 1 inch lower triple clamps. The rear shock is different: 1 inch of stroke is equal to 2-4 inches of rear seat lower. The 2-4 inch difference is due to the shock linkage being non-linear.

    When you change the rear suspension by modifying the shock clevis mount and/or the shock linkage arm length, you lower the rear of the bike more than the Yamaha designed amount and this will result in the fork having more trail and a more relaxed angle, often referred to as a chopper look and performance. (Chopper as in Harley Davidson choppers.) This will result in very stable and slow steering. To get the front back to a more vertical angle and faster steering, you must lower the triple clamps or shorten the forks. There has always been speculation about how much to lower the front end. Should it be identical to the amount of rear lowering, or more, or less.

    Here is what I show on my WRR mods page:
    "I lowered the triple clamps on the forks about 18mm as suggested by YamaLink and others. Although this amount is less than the rear, it seems it is appropriate considering the differences between how forks and shocks+linkage work."
    http://rickramsey.net/WR250Rmods.htm#lower

    The folks that sell the YamaLink have posted somewhere in this massive thread that the front and rear don't have to be lowered the same amount. I have verified that statement but I also attempt to lower the triple clamps as much as possible. Here is the maximum I have been able to achieve, about 25mm with the Easton EXP bars I installed later:
    [​IMG]

    I could get more with taller risers or shortening fork travel with internal spacers, but I find that the steering is acceptably quick with what I have here. You may want more or less.

    This is my distilled knowledge of how it all works; there are other opinions out there; let Google be your friend. In particular, there are nay-sayers who contend that changing the suspension to lower the seat is unacceptable to them. They say the suspension performance is negatively affected, that you will catch your foot pegs on ruts, and that any lowering is dangerous. The bike will bottom out by hiting the lower frame rails on the ground or the fender will hit the tire are also mentioned.

    No matter what anyone says, once you get the seat lowered to your preference and the suspension performing how you like, be happy with your bike. It will be set up the way you want it.

    If you can't ride the bike in stock trim then your (and mine) only choice is to lower the seat.

    /Flak Jak on. :ricky
  9. ba_

    ba_ Long timer

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    Thanks for the explanation ramz. :thumb

    Lowering with the stock adjustment is such an easy modification that it certainly will not hurt to try it. Same with lowering the forks in the triples.

    If it doesn't feel right I can always change it back.
  10. pfy50

    pfy50 Professional nOOb

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    ba_,
    I don't know if this will help any, but I don't think there is any definitive source. Each suspension guru has his own accumulated ideas as to how to set SAG and suspension. From what I've read though the MAX drop at the rear using the OEM linkage and Yamalink combined is 2.0"(50.8mm)before you start to run into handling problems and the MAX raise on the front forks is .71"(18mm) so a direct mathematical ratio is 1:2.82(front to rear)
    drop It may not work perfect, but it will give you a point to start at while you determine if the front end is too light or plowing in(slow) with your weight distribution setup.Don't forget to Set the SAG after.
  11. ba_

    ba_ Long timer

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    :thumb
  12. pfy50

    pfy50 Professional nOOb

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    Hey ba_
    Where in Westchester co. are you? I use to live just over the bridge in Bergen co. NJ
  13. sturgeon

    sturgeon Been here awhile

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    Combined with a Yamalink and some 'stock' lowering on the shock (don't recall exactly how much), it gave me the seat height I was after plus the steering response I liked. I experimented a bit with the front; 15 suited me best. 0-10 was too imprecise and 20-25 was too quick. Less than 5mm changes I really couldn't feel that much. I've also got a GPR damper. I really think one needs to play around a bit to get the best result. I followed the Yamalink advice to get a starting point.

    Dyslexics untie!
  14. BlockPass

    BlockPass Been here awhile

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    Just picked up 2008 model, with FMF Power Bomb header, Q4 muffler, but no air box mods or power programmer. The bike has a bad stumbling at small throttle opening, not just immediately off idle which I see many references to, but if you hold it just barely open it will stumble along, clearing up once you crack it more open and get the revs up. It is very pronounced when cold. Thoughts?
  15. r6realtor

    r6realtor Been here awhile

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    Well its an r but I have been doing my best to make it an x
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  16. thumpididump

    thumpididump MacGyver

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    Not surprising it has a bad stumble. You need a fuel programmer, and ideally, the intake system should be modified to allow more air to enter the engine. Allowing the engine to exhale better with an aftermarket exhaust system is good for increased performance, but without equal modifications to allow tbe engine to inhale more air, and by not adjusting the fuel metering, you've only achieved an upset in the fuel/air mix ratio. You need to keep air intake, air out (exhaust), and fuel metering in balance.

    Get an FMF programmer and remove the airbox flapper to start.

  17. noahdr

    noahdr Adventurer

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    very nice! Did you buy the black plastics and vinyl?
  18. r6realtor

    r6realtor Been here awhile

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    yes bought all new black plastics then had custom graphics made on the internet, once sent to me I had my local sign shop laminate them as the clear 3M coating was almost nonexistent,(there going to be tough to scratch now) they also put the graphics on the plastics for me man it was a s.o.b.!
  19. soupknotzee

    soupknotzee Been here awhile

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    Did you paint the plastic muffler shield with some aluminum look paint?

  20. r6realtor

    r6realtor Been here awhile

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    no totally stock