Yamaha WR250R Mega Thread

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

  1. onetravdown

    onetravdown I can't ride where?

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    Yes, they definitely suck and will not stand up to much abuse. I think you just had 'one of those days'. It happens.
  2. Chadx

    Chadx my toot toot

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    First, is it correct that the bike runs perfectly when there is enough fuel in the gas tank that the primary pump picks up the fuel directly and doesn't rely on the secondary pump?

    The secondary pump works off of vacuum so will only move fuel if there is adequate vacuum. Check all vacuum lines. Not only the vacuum line from the secondary air pump, but all other vacuum lines or capped off nipples to ensure no vacuum leaks. The secondary air-driven pump themselves don't have much that can go wrong with them and are very reliable. A vacuum issue is the likely culprit.

    Also, to test, stand the bike upright and put a splash of gas in the gas tank directly on the fuel pump (read: in the primary fuel pump dish) so the primary fuel pump has plenty of gas to pressurize the injector. Start the bike and, with it running, look down into the tank through the filler hole to determine of the secondary fuel pump is pushing fuel into the dish of the primary fuel pump.
  3. skierd

    skierd Wannabe Far-Rider

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    Doing an X swap, right now actually, with a guy from Philly. Ran into a snag on the front brake line... how do we disconnect the pressure sensor to remove the brake lever and mount from the handlebars and transfer them between bikes?

    THanks
  4. madisonreid

    madisonreid Long timer

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    Will pass on...Thank You.
  5. onetravdown

    onetravdown I can't ride where?

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    If you look next to where the connector goes, there is a hole on the underside of the lever. You have to push the little plastic tab on the connector and then pull it out.
  6. Jäger 1

    Jäger 1 Osons

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    I hate myself right about now...

    [​IMG]

    I can't tell until I get the swingarm off, but they look pretty deep.

    And I have no idea how I got to this point... I'm a mechanical klutz, but I also try and stay right on top of maintenace to try and avoid having my skills put to the test.

    I run stock sprocket sizes right now: 13/43, so this won't be a debate about 12 tooth sprockets. I'm more of a backroads motorcycle tourist gawking at the scenery than anything else, so not a lot of hard on/off the throttle.

    I changed out my rear tire again about four weeks ago. In the process of adjusting chain tension, etc, I inspected the swingarm chain slider or whatever it is called (I'm away from home right now, from my computer as well as service manual and whatnot) as I usually do. Didn't appear to look any different than previously, still seemed thick enough. Maybe I didn't look as carefully as I should have. Chain tension was set as per spec, about 8mm below the swingarm when under upward tension.

    Lubed the chain last about two weeks ago, didn't see anything unusual although I didn't look at the front sprocket while doing this. Certainly no red dust on chain.

    Weather has been atrocious around here since early May, so the riding as has been overwhelmingly on the slab, not my usual riding habitat on potholed and washboarded dirt roads - so presumably, a lot less rear shock/swingarm travel happening. But with my WRR my only transport right now, I have been riding it in everything including rain and have been piling up miles faster than normal.

    Coming back to the jobsite last night I felt the chain skip. Hmmm... loose chain. Just went out to deal with that, noticed that the rear chain had a deep red dust look to it. Which didn't give me a real good feeling because there's nothing like that around here for soil, but I hadn't put things together yet. Also noticed this chewed section of the mud flap, which I don't remember before, and may or may not have anything to do with this.

    [​IMG]

    Anyways, got the grunge brush out, cleaned the chain up, so never got a picture of that. Adjusted the chain and found it was very, very loose. Way loose. No damaged or broken sprocket teeth that I can find. So it got that sloppy loose in very short order - possibly signalling the chain is worn to the point it will stretch rapidly from now on? That possible? The chain and sprockets are still okay, not hooked, but certainly approaching the end of their service life.

    Once the chain was cleaned and lubed, I went to the front. Took the sprocket cover off, saw the damage, and positively freaked. If they sold ass-kicking machines, I'd rent one right now and use it on myself for about an hour.

    So I have no idea how I screwed up badly enough for this to happen - and to happen this quickly and to this extent. I've also never had my chain go loose that quickly before, and to be so badly slack. I always torque the rear axle nut to spec, and it certainly felt that tight when I loosened it off today to adjust chain tension.

    So down to the questions:

    First, suggestions as to how I screwed up bad enough to do this? I've been watching that swingarm protector ever since the first reported case of this happening, but obviously I wasn't watching carefully enough.

    Second, I have to run out again on the job so don't have time to start searching right now. Suggestions for places likely to have this in stock and a quick turnaround time for delivery? There's sportsplaza somewhere and a Honda place? Might as well make it someplace where I can get a new 14 tooth and 49 tooth rear sprocket with whatever bolts and a 112 link, master link chain as well... aside from approaching end of life, I don't think it did the chain any favours running in those aluminum grooves and it probably should be done on the same time. Suggestions on the sprockets to order also greatly appreciated as I'm supposed to be working here, not surfing the internet shopping.

    Third, there's no Yamaha shop here and no JB weld available to throw on to protect the swingarm from being eaten further. Home, Yamaha shops and all that good stuff is about a four hour ride away on the slab. So my options appear to be to sit picking my nose and wait for packages to arrive, pay somebody going in my general direction to truck the bike back home for me, or ride it as it is for that ride.

    I'd prefer to ride it home IF that can be done in some manner that won't add further damage in four hours - I don't know how thick the swingarm is at that point, but the last thing I need right now is to finish eating right through it.

    The chain was adjusted to about 8mm swingarm clearance as per the Yamaha chain tension adjustment update. I rode the bike for about 200 yards, just idling along in second gear. I think I might have heard a ticking noise that might have been the chain hitting the swingarm, but at this point I don't know if it is my now hyperactive imagination or not.

    With a properly adjusted chain (presumably tightened on the tight side of the adjustment scale), is it possible to ride in a manner that the conditions under which the chain would touch the swingarm are eliminated? Super smooth on and off the gas, avoid bumps that work the rear suspension as much as possible, etc? I don't know the mechanics of what causes the chain to come off the bottom of the front sprocket and pick up into the swingarm, so I'm not sure what to do at the moment.

    If it can't be safely ridden in some manner, then I guess I pay for a truck ride or I sit here until some packages arrive...

    Thanks for any suggestions and help. Off to work for a few hours where I'll have lots of time to work myself over for being negligent enough to allow this to happen.
  7. kawagumby

    kawagumby Long timer

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    Is the chain hitting the bottom of the swingarm? I couldn't quite tell from the picture. The chain would be loose under the swingarm during acceleration and loose on top during compression deceleration.

    There's a good chance if you adjust it fairly tight - and avoid large bumps (that could possibly stretch the chain further when tight) and avoid hard acceleration and deceleration - you won't have any problems. Using your brakes with no engine compression braking (pull in the clutch) will keep the chain from stretching more during deceleration. Softer, smoother acceleration will do the most for maximizing the bottom swingarm clearance.

    Be sure to check the chain link by link to make sure nothing is actually failing, that this is just a case of a quickly wearing chain.

    Good luck!
  8. skierd

    skierd Wannabe Far-Rider

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    X change complete! Found the tab, thanks trav.

    [​IMG]

    [​IMG]

    Can't believe how different it rides now, much smoother and much faster and lighter steering. Suspension feels like it works better too. I think im gonna like it, like a whole new bike now.
  9. RichardU

    RichardU Let's Ride

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    Those are typically acquired in a process called a wedding.

    That sounds like really fast chain wear. I agree with checking the chain thoroughly, and see the bike is riding low for any reason.

    If I wanted to ride it without repairs, I would check it every five minutes to start with and increase the interval after I had a sense of what it was doing.

    From what I could see of the picture, it looked like filling it with liquid steel, JB Weld etc. would do the job.

    This is the reason I keep a spare chain slider.
  10. andy mac

    andy mac Adventurer

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    Apr 12, 2009
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    Possibly your chain has some tight links and you adjusted the tension to the loose links, therefore when the suspension compressed and the tight links rotated, the too tight chain began sawing into the swingarm slider (seal guard). This is easy to do last week I overcompensated with the chain adjustment too.

    Here's some part numbers and contacts -
    JT front sprocket JTF1590SC-14 <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:eek:ffice:eek:ffice" /><o:p></o:p>
    JT rear sprocket JTR245/2-49 <o:p></o:p>
    Seal Guard swingarm 3D7-22151-00-00<o:p></o:p>
    Front sprocket nut (part number not phone number) 9079-18010<o:p></o:p>
    Chain 112 links<o:p></o:p>
    <o:p></o:p>
    http://www.yamahasportsplaza.com/pages/OemParts 503-669-2000
    <o:p></o:p>
    http://www.servicehonda.com/
    <o:p></o:p>
    http://www.cyclepartswarehouse.com/default.asp 866-926-2427
  11. onetravdown

    onetravdown I can't ride where?

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    Glad you got it! Don't you love how much different it feels on the road? Just like you said, it's quicker and the turn in is so much faster. I'm so happy I have the X wheels to put on when I'm using it for street duty. We'll have to go for a ride sometime since you're relatively close to me.
  12. onetravdown

    onetravdown I can't ride where?

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    After Jagers post about his chain eating into his swingarm, I decided to check mine. I've been meaning to do it for a while but kept putting it off. I pulled my slider and found some wear. Not as bad as Jagers obviously. But still significant enough to park the bike until a new slider arrives before the damage is worse. Here is what I found.

    8600 miles worth of wear. 2000 of which I was running a 12t sprocket.
    [​IMG]

    The chain has made contact with my swingarm. A small rub mark that's slightly gouged. Nothing really to worry about once the new slider is installed.
    [​IMG]
  13. GotMojo?

    GotMojo? Long timer

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    I thought the whole chain eating into the swingarm thing was caused by running the chain too TIGHT, not too loose. I think BigDog discovered this similar problem on his WR250R and now he specifically says on his website that he runs the chain looser than the manual says so that it doesn't wear into the guide at all.
  14. HighFive

    HighFive Never Tap-Out

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    If it has been run dry, the secondary pump may have lost its "prime". If you used a Tee fitting to tap the vacuum line, you can help re-establish its prime by temporarily diverting all vacuum force to the secondary pump....i.e. block off the vacuum to the other direction (flapper, etc), if applicable. Just slide a temporary vacuum plug onto the Tee fitting where needed.

    Meaning....make sure 100% of the vacuum is going to the secondary pump. You will need to fill the gas tank at least 1/2 full to get this going properly again.

    If none of that is effective, you may have a bad secondary vac-pump. Though, these little Mikuni pumps are pretty reliable (if you haven't messed with them....i.e. taken apart and reassembled).

    HF :thumbup
  15. onetravdown

    onetravdown I can't ride where?

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    That's probably what has saved my swing arm up to this point. I usually run my chain pretty loose. I know it's looser than what the manual says.
  16. Jäger 1

    Jäger 1 Osons

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    I already have that behind me, although I did avoid the process until after my 50th birthday.

    I really am pissed at myself about this, except I still can't figure out how I went from hero to zero in just a few weeks since the last time I was doing chain maintenance and checked.

    I'm as much on tippy-toes as I've alway been on the bike - still ignomously fall over sideways when I need a foot dab and the slope of the ground offers me nothing for support but air. Did that two days ago, in fact.

    There's no doubt the chain is at the end of it's life cycle. But my pedestrian riding habits while gawking at the mountains and scenery means there's no broken sprocket teeth, no hooking, etc - nothing gross looking. Felt fine right up until I felt the chain skip on the sprocket yesterday. The intent was to run this sprocket chain until a few weeks before my Montana/Idaho trip this summer, then go to my intended 14/49 setup and a new chain.

    Don't have a new chain to compare it to for feel and deflection, but it does seem to have an awful lot of side to side play in it. In any case, with this happening, the sprockets and chain change will be happening at the same time I do the swingarm repairs and service.

    Once and if I leave camp, it's all or nothing, no inbetween. It's get all the way home or turn back. I rode it a couple of hundred yards with the chain again back at Yamaha spec - 8mm. I swear I could hear links "tink"ing off the swingarm. But by then I was probably hypersensitive enough to noise that I was probably just hearing memories of last year's rides.

    I'm assuming and hoping it is no more than an ugly scar. I will make a feeler with a bent flagging wire tomorrow and scratch around the bottom of the worn parts. Hopefully I won't feel it drop into any cavities...

    I've never done the JB Weld thing before and there's none to be found here. I guess I'll get my first experience with it, followed by some time with patterning files and a Dremel, once I get back home.

    Seal protector...

    I guess I will now as well. I figured I'd have lots of warning as it got close, but it went from what looked like lots of meat left to this in just a couple of weeks

    I suppose. I'm a mechanical klutz, so anything is possible. I'm going to guess it is unlikely, however, because I generally don't trust myself with tools and check everything I do again and again.

    To tighten my chain, I loosen everything up, leave it on the sidestand, and then adjust the slack adjusters until it is at the slackest end of the recommended tension range - 8mm space between chain and swingarm at the midway point.

    Once I'm happy tension is right, it goes up on the stand and I use a Motion Pro alignment tool to ensure the chain is correcly aligned. I spin the rear wheel a few times while doing this to ensure I haven't loaded the chain somehow or other. Then the slack adjusters get locked down. Then it goes back over on the kickstand to ensure the tension has not changed and is within adjustment specifications. Once everything still looks all good, a little dab of blue Locktite and I torque the axle nut down to the specified torque. A final check on tension and alignment to ensure there have been no shifts, and then the chain guard goes back on and I call it a day.

    Seems it would be hard to adjust to a loaded part of the chain using that scenario.

    Thanks a lot Andy.

    That has been the general concensus. However, if anything, this was caused by a chain too loose.

    I was surprised when I felt the chain skip on the sprocket so quickly after the last adjustment. When I checked it this morning, the chain was so loose you could easily press one or two links up against the bottom of the swingarm. The front of my Sandman case saver had wear marks, presumably from the front sprocket spitting the chain against the case saver because of how loose it was. The axle nut was still tight enough it took the usual stomp on a small breaker bar to loosen it off from the factory torque specs, and the slack adjusters were all tight and properly in place.

    I'm at a bit of a loss how this happened in the first place, and also happened so fast. I've been checking this area probably more often than anywhere else, precisely because numerous people have written about having this problem. I thought I would get ample warning things were about done, but obviously not.

    Like to learn how this all happened so quickly, before this happens again.
  17. skierd

    skierd Wannabe Far-Rider

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    I posted most of this in your WRR forum thread, but it should be put here too. Quick question, whats your mileage?

    Long story short, I think the general consensus is wrong regarding slider wear.

    The guy who swapped his X wheels with me earlier today, Josh, his X has ~6700 miles on it now and the slider looks barely worn. Almost brand new even, with a little wear at the pivot. Stock sprockets and chain, both in good shape. It kinda solidifies my theory that the terrain that you ride on, namely how often the swingarm goes above horizontal while riding at speed, determines the wear on your chain slider more than any other factor. His bike was mainly commuted on and never really worked, mine has probably bottomed out half dozen times in regular trail riding and gets works on a semi-regular basis but not as often as an aggresive rider who uses his or her WR250R as a plated dirt bike. Remember that the sprocket is above the pivot bolt for the swingarm, therefore any verticle motion of the swingarm above horizontal will drive the chain into the swingarm by necessity. The wear pattern supports this, as the majority of the wear is at the pivot followed by at the feed to the front sprocket at the front of the swingarm/slider. That section is only going to be in contact with the chain when the swingarm is above horizontal.

    A 12T exacerbates the wear because of its smaller diameter causing the angle of attack of the chain at the swingarm pivot to the greater than the 13T, which in turn is greater than the 14T. Those of us who found excessive wear with a 12T probably found trails and rides that worked the suspension enough to cause the wear slowly with a 13T, but with the added angle with the 12T it gets worse. This scenario, where terrain matters most, is the only thing I can think of at the moment that would explain why lowered vs' stock height bikes doesn't show a dramatic difference, as everyone rides at a different level of aggression and on different types of terrain regardless of ride height, and why the various tensioning methods seem to have inconclusive results in regards to preventing chain slider wear.

    So my point is, its likely more the fact that you beat up and down washboarded and otherwise shitty/fun roads and trails that causes your suspension to flex a bunch more and therefore wearing the slider than any inattentiveness to maintenance. Proper tension is still important for all the reasons its important (chain, sprocket, transmission life, etc) but I don't think it is the cause of the slider wear.

    To add, some data points from my own experience. I have always set my chain tension the same way on both my WRR's: adjust it so that I can fit my index finger between the swingarm and chain on the underside about halfway between the chain guides and have the chain just barely touching my finger. I think it works out to 3/8" of clearance, but I don't remember how thick exactly my finger is off hand and no I'm not going to measure right now. My first WRR was never particularly punished off road and while it did a lot of traveling, I never did see the chain slider worn through. It ran a 13T and a 14T for its entire life until it was stolen with 17K miles. My current WR250R has been used for a lot of commuting and travel, but I have also gone out and used and abused it on trails, dual sport rides that were untimed enduro's, and lots of aggressive street riding but overall its usage would still be mild to medium in the relative scheme of things. Most of the aggresive riding was in the first 10k miles. I ran a 12T for about 6000 of that, during which time I wore through the stock slider. After changing the slider and sprockets to a 13/46 setup, except for one 120ish mile hard dual sport ride, its been all commuting and travel again. 17k on the current slider and its still going strong, about halfway to 3/4 worn. Most of my riding is on pavement, though a lot of it can be pretty bombed out and nasty in the city. If I rode there more often, or I rode on worse terrain more often, I'd gaurantee that my slider would be more worn.

    CN: Its terrain, not tension, causing the chain slider wear imo. If you ride hard off-road or even just ride a lot of bad roads for a few thousand miles, budget $50 for the chain slider every here and again and keep an eye on it.
  18. Chadx

    Chadx my toot toot

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    It'll be interesting to see how this swingarm wear pans out and which theories prove to be the cause. I can see how both the too tight and too loose theories could be plausible. I think skierd might be onto something, though. Not only the terrain, but more importantly rider and packed weight. If the bike is squatting hard due to weight and pulling the chain up towards the guard, there isn't much suspension travel needed for the geometry to be such that the guard seal (chain slider) is contacted. This even if you adjust sag correctly since the spring is ideal for a specific range and many folks are running heavier loads (heavier person or running with heavy gear packed on). I'm 170lb and usually have at least 10 - 20 lbs of gear with me. A lot of my miles are fast, slamming terrain, but realistically, the majority are not punishing the suspension in any way. The 3,000+ miles that I ran the 12/43 sprockets didn't really wear much on my guard and the 13/48 doesn't much at all. I did replace it (with pictures and details somewhere in this thread) at a mileage I forgot. Maybe 8.000 miles? I have one laying here for my wife's bike, but with 13/52 sprockets and her weight less than me, there isn't much of any wear on there. [Edit: found it. My pictures and details are here: http://mrchadx.blogspot.com/2010/08/chain-slider-guard-seal-replacement.html ]

    By the way, the part is listed as "seal, guard" so the correct phrasing is "guard seal" when we are talking about this part. Just like "cover, thrust" and "bolt, flange" are thrust cover and flange bolt. It's the usual way they list the parts with that comma in there. Chain slider seems more descriptive, though, and a more realistic name since this piece is not a seal. Maybe the comma was a mistake since seal guard would actually be more plausible than guard seal since there is a seal within the swingarm there (as well as bearings) and this would be guarding them against our chain digging through the swingarm to the seal. Maybe is was a matter of Japanese to English translation. :D
  19. kawagumby

    kawagumby Long timer

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    yep. Two things affect wear the most in my experience...the first is dirt and water - silicon is very hard and is abundant in dirt, water is the medium that delivers it into nooks and crannys - it grinds away at everything, and using a small front sprocket just makes things worse regarding grinding.
    The second is the geometry of the chain and suspension. Ideally, the swingarm pivot point should be the center of the countershaft sprocket, but that is impractical, so it is placed as close as possible behind it. This means that the chain tightens as it moves either way up or down - when you bottom out your suspension on a hit, the chain is much tighter than when it is level.
    If you are worried your chain might be too tight, you can compress the suspension to the max and see if the chain still has slack or not.


    As an earlier poster noted, chains often don't wear evenly, and worn ones often have sections that are tighter or looser than others, which means you should rotate the chain while setting slack, just to make sure you have the best average.
  20. bash3r

    bash3r I ain't no DingWeed

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    +1 This has been my thought, there's a definite reason for that swingarm slider, aka. "guard seal", to be there and made of good ole' plastic. There seem to also be a variety of factors that can play in your personal wear rate... weight of rider/gear(like Chadx mentioned), terrain, chain tight/loose, 12T or 13T, rear suspension setup. But ultimately it's just part of the gig, just like new tires.

    It's up to us to keep an eye on it, and not be surprised if it happens, swingarm guard seal needs replacing or some jb weld on the swingarm, or worse case, the swingarm needs replacing.. just keep an eye on it for sure! :thumb