Yamaha WR250R Mega Thread

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

  1. Dirtpatch

    Dirtpatch Getmesome

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    Bought a used wr and drained the 4 gal ims tank to fuel starvation. Good news went 100 miles on reserve. Bad news is had a couple inches in the wings where I could see gas left. Over the winter what do I adjust to run the wings dry.
  2. byron555

    byron555 Lame Duck Adventurer

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    What do you do when you have a 2000 YZ250 front end with 21" tire on an XT550 and want an sm wheel on it and you own an 08 WRx and want a 21" tire on it... swap forks and brake calipers of course

    [​IMG]

    [​IMG]

    This was my brother-in-laws Sunday project today... According to him the forks swapped over easy as can be, biggest pain was bleeding the brakes. The XT used to be his trail machine, but now he is thinking it will make a better sumo... I would agree with him there.
  3. what broke now

    what broke now Petroleum Brother

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    Aren't the yz forks longer than the wr's?
  4. pilacs

    pilacs Adventurer

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    Hi all, I'm thinking of buying one of these magic machines. Would the little machine be a good stablemate for my 990adv!? I'm planning a route from Florida to Canada to South Korea,Siberia,Mongolia and to Eastern Europe for next summer,about 12,000 miles. Would that be to much to ask from a 250R? I'm 6'1" 220. Thanks
  5. skierd

    skierd Wannabe Far-Rider

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    Too much? Hell it'll barely be broken in by then. If you're not looking to cruise at 80mph the whole time it's a great choice of travel bike. Mine broke 40000 miles leaving Deadhorse doing 90+mph with a weekend camping load. It's a durable bike.

    Those who've had engine issues typically have abused and really beat on their machines. Drowning, dirty air filter, running low on oil somehow, etc.
  6. BluePill

    BluePill AARP Slacker

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    One concern might be fuel quality & octane. Yamaha recommends 91 octane due to the high compression (11.8:1) and dirty fuel is tougher on high pressure fuel injection systems than carbs. Any failure of a high tech system in the boonies is a real problem. A basic air-cooled and carbureted motor is a lot easier to cobble a fix.

    You might want to research some ride reports here on ADV for the areas that you are going to, and see what experiences other riders have had.
  7. Luke308

    Luke308 Been here awhile

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    After changing my chain and sprockets, spark plug, etc. I rolled the bike outside and tried to fire 'er up. Fuel pump was priming, it turned over, bike in neutral, side stand up, etc. but not starting. :cry

    Started to run through in my mind everything I touched that I should go back and check, but I jumped on Google, typed in "WR250R won't start", read about the little trick of starting the bike with the throttle wide open, went outside and it fired right up. That's a good Ace to have up your sleeve before you go take apart the entire bike looking for the problem... :clap

    Oh, and this chain tension thing has me running around in circles, seems like half the folks here think it should be tight, the other half think loose, and when I push up on the chain the new chain slider interferes before I can get a good measurement from the swingarm.
  8. DougZ73

    DougZ73 Fading off.........

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    This picture worries ma tad bit. Overall, the slider does not look that worn compared to the new one right next to it. Looks nasty, but not worn too bad.

    What front sprocket were you running?

    EDIT: Check that...just realized I was looking at the top side not being too different..then realizing the bottom side is completely worn away. :huh
  9. TwilightZone

    TwilightZone Long timer

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    >"the other half think loose,"

    Yup. Run a 14 tooth sprocket in the front. 50 or 51 on rear.
    8K miles now on that setup...
    The swing arm guard shows no wear on the bottom.

    (I wore 4 of em out in the first 10K miles on the 250, 13T sprocket).
  10. Luke308

    Luke308 Been here awhile

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    Yep, it was the bottom side that is causing me headaches. I regreased my swingarm bearings last night and sure enough the bearings directly beneath the chain "furrow" have been compromised and are tough to spin by hand. I did not have the foresight to check that before I epoxied the furrow, so I'm unsure if it was from the hole itself, or my epoxy getting down in there. :scratch I'll have to fix it in the future, but I'll keep riding it in the meantime. Yes, it will wear funky, but I don't feel like it will make my swingarm fall off either...live and learn, eh?
  11. Luke308

    Luke308 Been here awhile

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    How loose is "loose"? :deal

    Just installed the 14/50 combo.

    Edited to add: I didn't realize how much the 50T reduces the clearance on the rear chain guide. Not a lot of gap there, but I guess at that point it's not a big deal since everything is pulled straight and tight at that location.

  12. jon_l

    jon_l Long timer

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    We keep perpetuating the idea that front sprocket size is the cause, but plenty of folks are running 12 and 13 sprockets without chewing up the sliders. I think after years of discussion, all we know for sure is that it must be caused by a combination of factors.

    Theories include front sprocket size, loading, and chain tension (both loose & tight).

    I have ~3,500 miles on a 12T front and minimal slider wear.
  13. simmons1

    simmons1 Long timer

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    I agree. I just changed mine out at 11.5K miles while I was doing other maintenance. It looked to be just over 50% worn through. I have used 12 and 13 tooth sprockets for the all of the mileage.
  14. coresports

    coresports coresports

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    you can destroy any bike by not breaking it in properly usually ending with a major motor malfunction at a much later date or by not properly maintaining it and at the same time running the crap out of it.

    i have owned several yamaha dirt/dual sports over the past 40 years and this one is the best i have seen so far. they are about as reliable as you can get, imo.


  15. byron555

    byron555 Lame Duck Adventurer

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    The 14t just makes proper chain tension less finicky. Greater tolerance for too tight. The thing is if you are in need of new sprockets and chain, why not go with the 14t and go with the higher margin of error?

    That is what I did, and it does work better, not that the 12t or 13t can work.
  16. TwilightZone

    TwilightZone Long timer

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    >"I think all we know for sure is that it must be caused by a combination of factors."

    Yup.

    That said... I don't know of anyone who prematurely wears out the chain guard after installing a 14T sprocket.

    Anyone else comment with a 14t sprocket - ie wearing out the guard ???
  17. Scott_PDX

    Scott_PDX Leisure Engineer

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    Agreed. I measured the difference in radius between the 12T and 13T sprokets and it's like 1/16" of an inch. So it could eat an extra 1/16" into your swingarm guard using the 12 over the 13, but that guard is like 3/8 thick, so something is accounting for the other 5/16" eating your swingarm guard that ain't the sprocket.

    Get a good chain, lube it well and often and keep the tension properly set and I bet that would solve most problems.
  18. Luke308

    Luke308 Been here awhile

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    Pushing up on the chain between the chain roller and chain guide bolt, I have the toolkit wrench width between the chain and the swingarm. Sound adequate?
  19. cjbiker

    cjbiker Nobody's Robot

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    It depends on the size of your sprockets. Larger sprockets put the chain further away from the swingarm. Also depends on how much the rear shock is compressed while you're measuring.

    There is one and only one way of determining the correct chain tension. Put the bike on a stand, remove the rear shock and lift the rear wheel until the rear axle, swingarm pivot, and countershaft sprocket are all in a line. Rotate the wheel to find the tightest spot in the chain and adjust the chain for a "little" slack at this point. Remember that if you're riding in mud the chain will tighten up as it collects mud, so a little extra slack (I like 1/2" inch or so) is good. This only needs to be performed once, unless you change your sprocket sizes. You can then put the bike back together and measure the chain slack in whatever manner is convenient for you. Always check it the same way, for the same value you recorded, and you're golden.

    Also note while you have the shock off that past the "everything in a line" point, the chain will contact the bottom of the slider. Your slider wear is proportional to the amount of time your suspension spends in this position. So, if your bike is carrying a heavy load and/or your static sag is too much, it will wear faster. It will also wear faster if you're riding a lot of rough offroad and the rear suspension is compressing to this point often. A smaller front sprocket puts the chain closer to the slider, so it will contact the slider more often as well.

    There are a few other outliers that can cause accelerated wear. If your chain is kinked, it will contact the slider as it comes off the front sprocket accelerating wear. If your chain is stupid loose, it will slap around and contact the slider more. If you get debris jammed in the rear chain guide, it can push the chain up and contact the slider.

    I also suspect that some chains tend to wear the slider faster than others. Some have nice rounded edges on the outer links and some are more square. This is just a theory at this point. More research is needed.

    There is no single reason why the slider wears. It is a combination of all of the above. :deal
  20. bluzharp

    bluzharp Adventurer

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    Lots of people seem resistant to compressing the suspension to line the countershaft, pivot, and axle up then adjust the chain. That is the best way to make certain the chain is neither too loose or too tight. It's pretty easy on these bikes with a ratchet strap to the sub frame.