Yamaha YZ 250 2018 Two Smoke!

Discussion in '2 smokers' started by WildAnCrazymtl, Mar 30, 2018.

  1. Yard Sale

    Yard Sale let's be bad guys

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    Nah, there's a KTM 300 mega thread in Thumpers. There's a Pitster Yamaha DT230-clone mega thread in Thumpers. The KDX thread is here, but they haven't made KDXs in twelve years or so.

    The mods should clarify Old's Cool 2 Smokers is for old bikes. (Almost all new 2 strokes are singles, not really "Thumpers," but whatever.)
    #21
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  2. tHEtREV

    tHEtREV Encouragement award recipient. tEAM iDIOT.

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    Most of those threads were started before this section appeared, and while this is a subcategory of the Olds Cool section, it is the only 2 stroke thread as stated, and there is a big KDX thread in Thumpers as well.

    Navin is all about Pitsters now, and most of the Orange brigade don't own anything orange these days...

    The world is a messed up place at the moment.:lol3
    #22
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  3. WildAnCrazymtl

    WildAnCrazymtl Political Prisoner

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    I suspect you are correct, however I asked a mod and was told to put it here, so I did! I did not realize Katie'M was over there... I hope this is not why this thread does not take off....
    #23
  4. WildAnCrazymtl

    WildAnCrazymtl Political Prisoner

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    When did this section appear?
    #24
  5. DSTEVENS

    DSTEVENS Been here awhile

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    In 2001 i bought a new YZ250, it was and still is the quickest bike i have ever ridden. Unbelievable power from such a small engine.
    Buy one and enjoy it while you can!!!
    Best wishes. D.
    #25
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  6. WildAnCrazymtl

    WildAnCrazymtl Political Prisoner

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    Sounds good! Any problems? Have you had to do the top end often?
    #26
  7. DSTEVENS

    DSTEVENS Been here awhile

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    I am sorry for such a late reply, I owned YZ for couple years and traded it in on something else. Trouble free for 2 years of hard riding and ran like new when traded, with original top end. I did not race it BUT ran it hard when i rode it.
    Best wishes. D.
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  8. WildAnCrazymtl

    WildAnCrazymtl Political Prisoner

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    Thanks man, I guess everyone is busy at work this time of year..... Lollll
    #28
  9. busa1300

    busa1300 Been here awhile

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    Can anyone tell me what the rear wheel HP is on a new YZ250?
    Wonder how it compares to late 80's to early 90's 250 GP street warriors that Japan put out for the home market.
    If there has been any real two stroke innovation in the past 25/30 years
    #29
  10. Hipower90

    Hipower90 I’ve breathed the mtn air, man

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    About 46+ stock.
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  11. Hipower90

    Hipower90 I’ve breathed the mtn air, man

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    I have an 18 X and 05 (first yr of the current frame). Both setup for hard techy offroad kinda stuff. The X is an absolutely awesome fun, capable, do-all bike.
    #31
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  12. Hipower90

    Hipower90 I’ve breathed the mtn air, man

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  13. Hipower90

    Hipower90 I’ve breathed the mtn air, man

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    X is $100 more then the mx.

    —same springs at both ends. Just different offroad valving. Noticeably better offroad then just resprung sss forks but with mx valving(as what my 05 has).

    —O-ring chain

    —Kickstand

    —18 rear

    Different tires. AT81 all terrains

    —3rd gear is actually closer to 2nd. Taller 4th and 5th. Much better since now that tall mx-ish first gear can be tamed for slower steep tech riding by final gearing change. But you still retain plenty of legs on top. Unlike the mx CR box.

    —Different engine tuning for offroad. Absolutely joy to ride on hard terrain

    —20% easier clutch pull. Via 10% softer springs. And 10% more efficient internal actuator. Different fiber disc material as well.

    —Same pipe tuning, but a whole new part number. It’s claimed to be tucked in 35mm closer. Yes, but I don’t see it being that much.
    #33
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  14. Hipower90

    Hipower90 I’ve breathed the mtn air, man

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    AB70237C-7583-4205-81B4-499D36F54681.jpeg AFCBB55F-E213-4FF5-9EBA-5A78165AC6CD.jpeg 8B9048C9-53B9-4333-A7A6-65A84861A88A.jpeg Today on the x in a remote area in the western NC mtns
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  15. snarlyjohn

    snarlyjohn Human money repellant

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    Most definitely, though with the decline in popularity of two-stroke bikes it hasn't been plainly visible, and the innovations have been subtle even if the performance gains haven't. Thanks to the work of Thiel and Overmar the Aprilia GP bikes of the 2000 - 2010 period made massive gains in output and even now are still very near the top of the heap.

    Their 125cc engines made somewhere around 480hp per litre, on gasoline, naturally aspirated. To put this in perspective, compare this with a CR500 Honda, a bike with a bit of a reputation for power amongst dirt bike riders. The 125cc Aprilia GP bikes made significantly more power than the CR with just 125cc.

    What changed then? There were lots of incremental improvements, but the biggest one was the recognition of the importance of blowdown. Auxiliary exhaust ports started to appear on some Japanese engines but it was Thiel and Overmar that fully exploited them. Blair had laid the groundwork with port time/areas but it was the quantification of the blowdown period that allowed the jump in horsepower to be realised. In a way Thiel and Overmar took over where Blair left off.

    Two stroke development continues today but you won't find much of it happening in bikes. And to be fair there's only so much power you can use (especially on dirt) so it makes sense that efforts would be spent on broadening the power range rather than raising the peak. A 100hp dirt bike might sound like fun but in practice 50 or 60 useable horsepower would be much faster. There are minor things happening like fuel injection on bikes like the KTMs and so on but these don't really do much for peak output.

    If you want to see the current state of the art you're better off looking at things like karts and snowmobiles. Engines like the Rotax E-TEC range are interesting, powerful and clean. In karts the most innovative design has been the controversial Ryger, a completely new two stroke design. Unfortunately though the Ryger has so far failed to deliver its promised horsepower and remains uncompetitive with conventional engines. Companies like TM produce modern two stroke engines for both bikes and karts.

    I guess the 500 Suter deserves a mention too. A lot of us 2T enthusiasts had high hopes for this but so far the race results have been disappointing. Ironically, it seems that they would have had much better results had they been able to run carburetors. FI is especially difficult to make workable with a two stroke and where it is used it seems it is more for emissions purposes. In a way the 500 Bimota V-Due was very similar - a bike that looked extremely promising on paper but in practice failed to live up to expectations due to shortcomings in the injection system.

    The big gains are in modern porting practices - I know of KTM 250s making 80+ horsepower mainly through modern port and pipe design.
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  16. WildAnCrazymtl

    WildAnCrazymtl Political Prisoner

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    The above was an interesting read! I am glad to see some interest in this thread. I have not yet went out to get mine yet, it seems with my new schedule, I would probably mot get to ride it much. I did find a new 2017 none "X" version at a fantastic price... I am really tempted even if the X would be more sutied to me....
    #36
  17. WildAnCrazymtl

    WildAnCrazymtl Political Prisoner

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  18. Hipower90

    Hipower90 I’ve breathed the mtn air, man

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    025A9618-3561-46FC-AA44-A66682CDC7D9.jpeg B3946BCB-94E2-4577-9685-E3465305AC31.jpeg
    #38
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  19. Hipower90

    Hipower90 I’ve breathed the mtn air, man

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    #39
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  20. Yard Sale

    Yard Sale let's be bad guys

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    My 2006 on its 10 year anniversary ride. (I bought it in November 2007.) No good reason to get a newer model or upgrade to an X model. When it's time to rebuild the crank I'll put in WR 3-5 gears and effectively have an X.

    [​IMG]
    #40
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