WR250R Cam Chain help needed

Discussion in 'Thumpers' started by simonpig, Apr 17, 2012.

  1. simonpig

    simonpig droppin' jewels

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    Whats up wrenching gods. I'm stuck. Heres the situation:

    After 20,000 miles, my WRR engine starting feeling loose. Seems like the Cam chain has developed some stretching, so I decide to order a new cam chain and am in the process of replacing it.

    Several mistakes were made in the order of operations:
    1. I remove the tensioner before spinning the crank to TDC mark on the flywheel. After several cranks, its seems like the valves stopped at their natural TDC position—as chain starts skipping on the cam gears, not sure?

    <a href="http://s1202.photobucket.com/albums/bb361/simonpig/?action=view&amp;current=986d5e61.jpg" target="_blank"><img src="http://i1202.photobucket.com/albums/bb361/simonpig/986d5e61.jpg" border="0" alt="Uploaded from the Photobucket iPhone App"></a>

    2. Second question is, How the hell do I remove the cam chain? Do I have to actually split the case? Or is there a chain breaker tool, master link setup, I'm missing? Its a continuous chain.
    #1
  2. clintnz

    clintnz Trans-Global Chook Chaser

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    Do you have the maintenance manual? If not get one. It's relatively easy to follow.

    It probably doesn't matter much if the crank isn't at TDC now, or where the valves are, it will matter when you go to reassemble. The manual will have detailed instructions on setting up the timing.

    Dunno about the WR but it would not be unusual to have to remove the head & some stuff off the end of the crank to replace a continuous cam chain.

    Measure up & compare the 2 chains before you install the new one - higher miles WRR's are rare & any info about what wears out & when would be very useful to those who are racking up the miles.

    Cheers
    Clint
    #2
  3. simonpig

    simonpig droppin' jewels

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    I do have the manual, and it looks like I will need to remove the generator, and some other stuff off the end, which worries me because I'm not sure if I need specialty tools.

    After doing some independent internet research, it looks like I've solved the first question—the answer being very simple. When going to reinstall everything, turn the Crank to TDC mark, set the timing marks on the cam gears to match with the lobes pointing at 10 and 2. Done.
    #3
  4. ttpete

    ttpete Rectum Non Bustibus

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    You'll probably need a puller to remove the alternator rotor.
    #4
  5. Pete-NZ

    Pete-NZ Been here awhile

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    Brake the old chain... brake the new chain..join them togeather
    pull the new one though as you pull the old one out... disconect the two
    re-pin the new one back togeather...
    The guys at the local Honda shop showed me that years ago..
    I have done 3 bikes that way...
    #5
  6. simonpig

    simonpig droppin' jewels

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    How do you rivet the pin back securely. Don't want to risk it breaking inside the motor. Save a youtube video where someone tacked it with a tig welder.

    Bought a rotor puller and am waiting for that to arrive. The other tool called for was a sheave for holding the rotor, but I have a impact wrench so don't need it for removing, though reinstalling might be a problem?

    #6
  7. ttpete

    ttpete Rectum Non Bustibus

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    I don't think you'll need to break the chain on that one. That's done on multi cylinder bikes that have the chain coming up between the cylinders.
    #7
  8. markk53

    markk53 jack of all trades...

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    Your bike uses a HyVo chain. It should not wear out in 20,000 miles, they should last the lifetime of the engine. If it is worn out it would be the fault of a junk cam chain tensioner. I do know about those since I've been involved in making tensioners for Kawasakis and now Hondas for the past three years. Automatic tensioners mostly suck in design, especially the ratchet style. That is how I got into this, junk tensioners in two of my bikes.

    Measure your cam chain over the prescribed number of links to see if it actually IS worn out or if you are dealing with a JUNK tensioner. My bet is at the least the tensioner is junk, possibly chain too, but possibly not if you're lucky. There is no way in hell I'd ever put an automatic cam chain tensioner back in a bike if the cam drive failed. I went through two OEM tensioners in my KLX650 in less than 14,000 miles, the last one allowing the cam chains (2 on the 650) to wear beyond tolerance.

    After installing the manual tensioner I have over 30,000 miles with only about .050" adjustment made as the new HyVo chains seated in. Virtually no adjustment in the past 10,000 or more miles... I forget when I last did it. You adjust the tensioner when the engine is at full operating temperature if the cam drive ticks, not clatter, but ticks. I also had to put a manual tensioner in my Zephyr 550 - that was actually one I had to make so when I did I made five of them and sold the five. It kind of blossomed.

    If you want to take care of the tensioner issue, contact me and I will see what can be done for a manual unit for less than any other company will sell one, probably $30 plus shipping. I have fitted one for a YZF425, but don't know if it fits up to any others. It is identical to that of a KLX650, but uses a different thru bolt set up which is no big deal. All I need is the pattern of the tensioner body.

    Here is a sample of my work in a KLX250:

    [​IMG]

    If you want references for my abilities should you need them, just do a google search on Krieger Cam Chain Tensioners. Like I said earlier, it kind of blossomed. I've sold tensioners in 29 countries and I think now to all 50 states in the U.S. and all provinces of Canada, to the tune of around 700-800 units. You'll find a lot of satisfied riders, including some on this forum. You may find where I worked with a KLX250/300 rider to make the tensioner (apparently the only one available for them). I can help if needed. Email me from here if you wish.
    #8
  9. simonpig

    simonpig droppin' jewels

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    Interesting. I had a feeling it might be the hydraulic cam chain tensioner. The only thing is that upon inspection, you cant tell its working or not since it relies on oil pressure.

    The cam sprockets look ok to me, and not worn at all. I was going to pull the rotor today and pull the chain to compare it to a new one to see. You mentioned measuring it while on the crank. How do you do that?

    FYI, just want to note this the WR250R dual sport model and not the 250F racing yamaha's. Does this manual chain tensioner work on my bike?

    #9
  10. simonpig

    simonpig droppin' jewels

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    Rookie mistake, bought a rotor puller 33mm x 1.5 outside thread, as opposed to "M33" x 1.5 inside thread puller. Arghhh. Oh well, must stay zen...

    Pulled the generator cover today, zipped off the rotor nut with an impact wrench, but had to leave the guts open until I can get the proper tool.

    Going to see if I can borrow one from a friends shop tomorrrow.
    #10
  11. markk53

    markk53 jack of all trades...

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    I've been in touch. I am getting a gasket to do the job, we'll communicate on this. I've done the CBRF/F2 and the CBRF3/F4/F4i tensioners which used oil pressure. They just block off the flow, no problem.

    There should be a spec for measuring the cam chain while on the bike if it is a dual overhead cam. It is measured from one pin to another over a certain number of teeth. Unless you have several thousand miles with a junk tensioner, I'm betting it's still good.
    #11
  12. simonpig

    simonpig droppin' jewels

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    Was able to borrow KTM spec generator rotor tool which worked. Finally pulled the chain and compared the old with new. Guess what, the chain is fine.

    <a href="http://s1202.photobucket.com/albums/bb361/simonpig/?action=view&amp;current=69254399.jpg" target="_blank"><img src="http://i1202.photobucket.com/albums/bb361/simonpig/69254399.jpg" border="0" alt="Uploaded from the Photobucket iPhone App"></a>

    It was a hassle tearing into the engine to find this out, but I don't mind. I'm happy to have the experience.

    Now I know the chain isn't the fault, it just must be something with the tensioner.

    The only other thing would be that the valves are so bad out of spec that its causing the chain to feel like it's loose inside the engine? Is that even possible? I'll leave that to more experienced mechanics to explain.

    Going to put it all back together and then check the valves to see where they're at.

    <a href="http://s1202.photobucket.com/albums/bb361/simonpig/?action=view&amp;current=098d00a4.jpg" target="_blank"><img src="http://i1202.photobucket.com/albums/bb361/simonpig/098d00a4.jpg" border="0" alt="Uploaded from the Photobucket iPhone App"></a>
    #12
  13. simonpig

    simonpig droppin' jewels

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    Thanks for reaching out. Let me know if you'd like me to make any measurements for you to the existing tensioner or to take pictures of it.

    #13
  14. simonpig

    simonpig droppin' jewels

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    Measured Valves today to order shims for adjustment, the readings after 20K are as follow:

    EXHAUST
    Left: .009" (.23 mm)
    Right: .010" (.25 mm)

    INTAKE
    Left: .005" (.13 mm)
    Right: .004" (.10 mm)


    The Factory Specs are
    EXHAUST: .0091–.0118" (.23–.30 mm)
    INTAKE: .0051-.0079" (.13–.20 mm)

    Not bad for 20K, no?
    #14
  15. Jedaha

    Jedaha Adventurer

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    Clearances look good for the mileage, when comparing to my WR250F I just rebuilt the head after 6,000 kms.
    I was adjusting the shims every 1000 k's, it drove me mad, thats main reason I bought a WRR.

    The WRR I bought has 10,000 km on it and it too sounds like the cam chain is slapping around a bit.
    Especially when you rev the bike and the revs fall back, there is a clatter at a certain rpm.
    Have you resolved your would be tensioner issues.

    As far as the timing chain is concerned mine on my WRF was stretched at 6000 Km as cam marks could no longer be aligned, so I replaced it. It's good that the R model is not wearing them out as quick.
    #15
  16. simonpig

    simonpig droppin' jewels

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    Waiting on the manual tensioner from Mark Krieger to be produced. Sent off some measurements and pictures.

    Hope it will be soon. Don't want to put another automatic tensioner on it really. Also the manual tensioner will make it easier to install the cams and to set the timing marks more easily. It took me nearly 10 or so tries to get the timing mark set up properly with the stock setup.

    #16
  17. Jedaha

    Jedaha Adventurer

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    Yeah, I'm waiting on the tensioner from Mark also, before I look into it any further.
    (Good riding weather here ATM)

    I recorded a video of the noise, but surprisingly you can't hear the clattering noise on the video.
    Anyway I have a before video.
    If the after (new tensioner) video shows a difference, I will post them.
    I will try and do a better before video, before pulling down, I suspect the exhaust is making the cameras auto volume attenuate the chain noise.
    #17
  18. simonpig

    simonpig droppin' jewels

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    The Krieger Manual Cam Tensioner came in the mail today. Going to the garage this evening to start the install. Pysched. Heres some pictures.

    Thanks Mark, I will keep you posted.

    <a href="http://s1202.photobucket.com/albums/bb361/simonpig/?action=view&amp;current=P1020860.jpg" target="_blank"><img src="http://i1202.photobucket.com/albums/bb361/simonpig/P1020860.jpg" border="0" alt="Photobucket"></a>

    Old vs. New

    <a href="http://s1202.photobucket.com/albums/bb361/simonpig/?action=view&amp;current=P1020861.jpg" target="_blank"><img src="http://i1202.photobucket.com/albums/bb361/simonpig/P1020861.jpg" border="0" alt="Photobucket"></a>
    #18
  19. Jedaha

    Jedaha Adventurer

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    Looks good, I'll see how yours goes then order one as well.

    Do you know what the allen key screw is for, on the old tensioner, the manual doesn't mention it from memory.

    Will be interesting to see how this fits in with the starter motor, it almost looks like the length will need to be custom cut once installed, and adjusted close, to get the starter motor back in.

    You can aways remove some length, it's a bit hard to add it though :wink:
    #19
  20. simonpig

    simonpig droppin' jewels

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    Finally got to installing it on friday night and as envision made the job of aligning the timing marks SO much easier.

    Before going any farther, I loosely installed the starter motor to see what the clearance was there.

    <a href="http://s1202.photobucket.com/albums/bb361/simonpig/?action=view&amp;current=P1020864.jpg" target="_blank"><img src="http://i1202.photobucket.com/albums/bb361/simonpig/P1020864.jpg" border="0" alt="Photobucket"></a>

    <a href="http://s1202.photobucket.com/albums/bb361/simonpig/?action=view&amp;current=P1020865.jpg" target="_blank"><img src="http://i1202.photobucket.com/albums/bb361/simonpig/P1020865.jpg" border="0" alt="Photobucket"></a>

    No dice. The Acorn nut at the end wasn't allowing the press fit starter to seat.

    <a href="http://s1202.photobucket.com/albums/bb361/simonpig/?action=view&amp;current=P1020868.jpg" target="_blank"><img src="http://i1202.photobucket.com/albums/bb361/simonpig/P1020868.jpg" border="0" alt="Photobucket"></a>

    So I cut 8.6mm (.34 inches) off the end and removed the acorn nut, but left the smaller locking bolt.

    <a href="http://s1202.photobucket.com/albums/bb361/simonpig/?action=view&amp;current=ccc30af3.jpg" target="_blank"><img src="http://i1202.photobucket.com/albums/bb361/simonpig/ccc30af3.jpg" border="0" alt="Uploaded from the Photobucket iPhone App"></a>

    I was then able to find the clearance I needed (barely). There enough room to back the adjuster out .3 inches, but I needed to used a small wrench and some small piece of rubber to protect the threads in order to adjust it.

    I left the small adjuster as an option on in the case I needed to used to larger main lock nut to lock to the smaller for fine tuning adjustments.

    <a href="http://s1202.photobucket.com/albums/bb361/simonpig/?action=view&amp;current=P1020876.jpg" target="_blank"><img src="http://i1202.photobucket.com/albums/bb361/simonpig/P1020876.jpg" border="0" alt="Photobucket"></a>

    <a href="http://s1202.photobucket.com/albums/bb361/simonpig/?action=view&amp;current=P1020877.jpg" target="_blank"><img src="http://i1202.photobucket.com/albums/bb361/simonpig/P1020877.jpg" border="0" alt="Photobucket"></a>

    <a href="http://s1202.photobucket.com/albums/bb361/simonpig/?action=view&amp;current=P1020879.jpg" target="_blank"><img src="http://i1202.photobucket.com/albums/bb361/simonpig/P1020879.jpg" border="0" alt="Photobucket"></a>


    Mark, because of the starter clearance issue, it might make sense to either machine flat .25 at the end of the threaded nut so that a wrench can used for leverage.

    Or drill it (safety wire style at the 12 and 6 postion/ and 3 and 9 positions) so that a small pin can be used to gain leverage to adjust the bolt in and out.

    <a href="http://s1202.photobucket.com/albums/bb361/simonpig/?action=view&amp;current=P1020880.jpg" target="_blank"><img src="http://i1202.photobucket.com/albums/bb361/simonpig/P1020880.jpg" border="0" alt="Photobucket"></a>

    Putting the bike back together was an exercise in focus. When going to refill the radiator, I forgot to connect a small hose and was rewarded with a coolant overflowing from the end of the temperture sensor hose.

    After that I bolted everything back, and put the gas tank back on, I fired it up. I was worried something was going to sieze or that I messed something up, but it seems to run fine. I started messing with the adjuster and could hear the the engine going from a "tick" to a "clack" when backing out the adjuster. Tuned it by ear where I felt the sound transition over and locked it there.

    Have a ride in a couple of weeks, so I'm leaving everything as is for now, I'll only need to adjust once every blue moon, so I'm fine with this solution.
    #20