KLR650 Front Sprocket swap step-by-step Walk thru

Discussion in 'Thumpers' started by klm4755, Jun 3, 2007.

  1. klm4755

    klm4755 Been here awhile

    Joined:
    Jun 19, 2006
    Oddometer:
    577
    Enclosed is a step by step walk thru to swap out the KLR650 front (drive) sprocket (15 tooth) with a 16 tooth PBI &#8220;after-market&#8221; brand. Since 99% of the KLR travels will be on pavement during my daily commute, I am seeking a less vibration environment. One way to obtain this effect is to lower the RPM&#8217;s while in 5th gear. The larger sprocket will reduce RPM&#8217;s by 7% for the equivalent speed. Do not loosen rear wheel or mess with the chain...yet<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:eek:ffice:eek:ffice" /><o:p></o:p>
    Sprocket can be seen here:<o:p></o:p>
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    http://happy-trail.com/ProductInfo.aspx?productid=MCY%2050-440XX<o:p></o:p>
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    [​IMG]<o:p></o:p>
    sprocket as delivered from happytrails.com<o:p></o:p>
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    annotations on packaging<o:p></o:p>
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    exploded view of configuration. Note represents a 2007 bike.<o:p></o:p>
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    remove sprocket cover<o:p></o:p>
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    The bolt to remove....27mm socket size.<o:p></o:p>
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    pry back the retainer clip. Easy to bend with prying screw driver<o:p></o:p>
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    like so<o:p></o:p>
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    [​IMG]<o:p></o:p>
    since a 27mm socket is very difficult/expensive a 1 and 1/16 size socket will fit.<o:p></o:p>
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    [​IMG]<o:p></o:p>
    Ok...the tricky part. <o:p></o:p>
    1. Place the bike on the side stand<o:p></o:p>
    2. Approach bike from right side and lean over placing your belly on the seat.<o:p></o:p>
    3. Right foot on rear brake...push<o:p></o:p>
    4. Right hand on front brake ...squeeze<o:p></o:p>
    5. Left foot on ground<o:p></o:p>
    6. Place socket on sprocket nut. Wrench handle pointing aft (toward rear). Left hand on wrench handle.<o:p></o:p>
    7. Lift left hand with all might to loosen nut. I used a 2 foot ½ torque wrench as shown above<o:p></o:p>
    <o:p></o:p>
    [​IMG]<o:p></o:p>
    spin nut off of threaded drive shaft<o:p></o:p>
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    like so...now jack up bike, remove rear axle and loosen chain<o:p></o:p>
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    [​IMG]<o:p></o:p>
    drive stud with sprocket on splines<o:p></o:p>
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    backoff view<o:p></o:p>
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    wiggle sprocket off splines. Out view side<o:p></o:p>
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    inner view side <o:p></o:p>
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    proper stack-up sequence<o:p></o:p>
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    [​IMG]<o:p></o:p>
    spline with sprocket off..inspect..no wear here. My bike has 2,000 miles logged<o:p></o:p>
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    [​IMG]<o:p></o:p>
    height comparison<o:p></o:p>
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    top view OEM 15 tooth over 16 tooth new<o:p></o:p>
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    new sprocket installed on spline<o:p></o:p>
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    add nut retainer and thread nut<o:p></o:p>
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    torque nut to 72 ft-lbs note units!<o:p></o:p>
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    [​IMG]<o:p></o:p>
    bend the retainer over the nut land area, use channel lock plyers<o:p></o:p>
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    [​IMG]<o:p></o:p>
    like so<o:p></o:p>
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    [​IMG]<o:p></o:p>
    replace sprocket cover, rear axle nut to 69 ft-lbs, and adjust the chain to spec.<o:p></o:p>
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    [​IMG]<o:p></o:p>
    cleaned up OEM sprocket<o:p></o:p>
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    [​IMG]<o:p></o:p>
    little to no wear after 2,000 miles<o:p></o:p>
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    [​IMG]<o:p></o:p>
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    Observations and Review:<o:p></o:p>
    1. Easy to swapout<o:p></o:p>
    2. Loosening the sprocket nut was the most difficult part<o:p></o:p>
    3. Little to no sprocket wear after 2,000 miles<o:p></o:p>
    4. Love the way the bike &#8220;feels&#8221; now<o:p></o:p>
    5. Feels like the 6th gear the bike has been missing.<o:p></o:p>
    6. Don&#8217;t miss the low end torque ...yet. Worth the trade for me.<o:p></o:p>
    Keithm<o:p></o:p>
    -----------EDIT Below------
    I have reviewed the install have included the option to shim and included a progressive torque nut from Arrowheadmotorsports.<o:p></o:p>
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    [​IMG]<o:p></o:p>
    progressive nut + 30mm socket for install<o:p></o:p>
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    [​IMG]<o:p></o:p>
    closeup of nut. <o:p></o:p>
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    [​IMG]<o:p></o:p>
    Note the crimped threads<o:p></o:p>
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    [​IMG]<o:p></o:p>
    sprocket shims<o:p></o:p>
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    OEM sprocket &#8220;Bike side&#8221; shown<o:p></o:p>
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    [​IMG]<o:p></o:p>
    shim ID<o:p></o:p>
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    shim OD<o:p></o:p>
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    would fit here, if needed<o:p></o:p>
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    sprocket gage at shaft location = .500 inch<o:p></o:p>
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    PBI aftermarket sprocket gage at shaft location = .501 inch, matches<o:p></o:p>
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    [​IMG]<o:p></o:p>
    Will flip PBI sprocket and compare with OEM<o:p></o:p>
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    try this, outside view<o:p></o:p>
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    inside view<o:p></o:p>
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    teeth align in this orientation. NO shims needed!<o:p></o:p>
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    [​IMG]<o:p></o:p>
    reinstalled with PBI markings inside<o:p></o:p>
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    torque to 72 ft-lbs<o:p></o:p>
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    [​IMG]<o:p></o:p>
    I&#8217;ll still use the supplemental nut locking device, just for extra safety<o:p></o:p>
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    [​IMG]<o:p></o:p>
    fold over a tab<o:p></o:p>
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    OEM fasteners replaced<o:p></o:p>
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    The PBI sprocket is an exact match without shims. Face markings on the inside face.<o:p></o:p>
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    <o:p></o:p>
    #1
  2. Max Kool

    Max Kool Xtankteam™

    Joined:
    Jan 19, 2004
    Oddometer:
    3,873
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    Los Angeles
    Very well documented!!
    #2
  3. shoco

    shoco Not So Gnarly Adventurer

    Joined:
    Nov 27, 2005
    Oddometer:
    476
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    Southern California
    Excellent write up. Thanks for taking the time to post this! :clap
    #3
  4. dgunther

    dgunther rides ugly bikes

    Joined:
    Feb 18, 2006
    Oddometer:
    226
    Location:
    Marietta, GA
    Nice write-up.:clap

    I realize the need to make do with what is on-hand, but it is best not to use a torque wrench for breaking loose the sprocket nut. You might damage it or cause it to fall out of calibration, increasing the chance that you could over-torque something important in the future.

    I use a cheap extendable 1/2" breaker bar I picked up at Harbor Freight or Northern Tool - you can try to mess up a whole bunch of those for less than the price of even the cheapest torque wrench!
    #4
  5. klr650tr

    klr650tr Adventurer

    Joined:
    Oct 17, 2006
    Oddometer:
    17
    Location:
    upstate,NY
    how about 17teeth?
    too much? anyone has it?
    #5
  6. Kbetts

    Kbetts Long timer

    Joined:
    May 25, 2005
    Oddometer:
    1,259
    Location:
    Location, Location
    I didn't put the locking plate back on with the prevailing torq nut....

    I thought the whole idea was not to need a locking plate for field swaping the CS.....

    Do I need to take the PT nut back off and stick the locking plate behind it and bend it over?

    Keith
    #6
  7. colomtnbiker

    colomtnbiker wimpy old guy

    Joined:
    Jan 19, 2006
    Oddometer:
    539
    Location:
    mountains of western Colorado
    The locking plate is not needed with the prevailing nut. That's the joy, just use a crescent wrench or something similar and you don't have to go through so many steps to change sprockets. I can change sprockets (13 tooth) on two bikes ( mine & my wife's) in about 30 minutes when we are going offroading. The prevailing nut is awesome.
    #7
  8. klm4755

    klm4755 Been here awhile

    Joined:
    Jun 19, 2006
    Oddometer:
    577
    The lock washer was just added for additional security. You know, I dress with a belt and suspenders.
    Keithm
    #8
  9. East Coast

    East Coast East Coast

    Joined:
    Feb 18, 2007
    Oddometer:
    144
    Location:
    PEI, Canada
    Just tried to do the gear swap this evening - "prior to reading this article", and was not sucessfull due to inability to get the nut off. I'll try your method. Did you make any changes to your chain tension?

    Thanks. Jt
    #9
  10. klm4755

    klm4755 Been here awhile

    Joined:
    Jun 19, 2006
    Oddometer:
    577
    Yes, the rear axle was moved forward just a tad to compensate for the slightly larger drive sprocket. No new chain needed though. Still very happy with the extra tooth.
    Keithm
    #10
  11. East Coast

    East Coast East Coast

    Joined:
    Feb 18, 2007
    Oddometer:
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    PEI, Canada
    Why did you remove the rear axle. Did you just loosen it to move it forward?
    #11
  12. klm4755

    klm4755 Been here awhile

    Joined:
    Jun 19, 2006
    Oddometer:
    577
    I removed the rear axle so I would not have to re-thread those chain adjusters. I have the fuji lockbolts.
    Keith
    #12
  13. CA Stu

    CA Stu Master of air potatofication Super Moderator

    Joined:
    Aug 27, 2004
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    Location:
    Riverside, CA
    [​IMG]

    <?xml:namespace prefix = o /><o:p></o:p>Hey man, I'm pretty sure that those washers are for the early model bikes (pre-96) that used a different method of mounting the drive sprocket that was prone to chatter and wearing out the splines, not for your bike...

    Do some homework and get back to me!

    Thanks
    CA Stu

    EDIT: from the FAQ:
    Mid-1996: Changed valve cover, added bracket to hold cam chain bumper; changed crank to heavier unit; improved clutch basket with more clutch plates; changed countershaft sprocket retainer from slotted plate to large nut; changed 2nd and 3rd gear ratios. Kickstarter no longer fits with new clutch basket

    On '95 and earlier models, two hex head screws hold a slotted retaining plate. Remove the screws, rotate the plate, and pull it off. Note that the retaining plate can get chewed up. Sagebrush Machine Shop makes a stronger replacement part, that gives full engagement of the splines rather than half.

    I believe those washers were sold as part of a remedy for this problem.


    And not to come off like a know it all, but even with zero maintenance, a stock OEM sprocket is good for at least 15k miles, the chain maybe 9 or 10k miles, and it's best to replace all 3 items (both sprockets and the chain) at the same time.
    Preferably before they look like this:

    [​IMG]
    #13
  14. CA Stu

    CA Stu Master of air potatofication Super Moderator

    Joined:
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    Um, what is the point of bending the washer over the prevailing torque nut?

    It's silly.

    A bent splined washer isn't going to magically flatten itself out and allow a sprocket that is on a splined shaft to fly off. :lol3

    Are you now or have you ever been inside a garage? :lol3

    Thanks
    CA Stu

    PS here are my instructions

    1) remove old sprocket
    2) Install new sprocket
    3) Go riding


    And, FWIW, I've tried other tooth count front sprockets, and here is my conclusion;

    The 15 is the best for every day riding.

    If you are one of those morons that enjoys thrashing your KLR where it should never go, the 14t is really good (sweet spot in rpm and speed for tough offroad in 2nd gear), and the 16 is OK if you live in Florida and hardly ever use your clutch.
    #14
  15. wheatwhacker

    wheatwhacker It's raining here

    Joined:
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    3,115
    Location:
    Cork, Ireland
    Wow, what a great article...........
    I did mine a year ago, went as follows.

    Step 1. Loosen rear wheel and slacken chain a little.
    Step 2. Take off 15 tooth sprocket.
    Step 3. Install 16 tooth sprocket.
    Step 4. Retighten chain, tighten rear wheel.
    Step 4. Check for gas, start motor, ride.

    Total time..............15 min
    #15
  16. klm4755

    klm4755 Been here awhile

    Joined:
    Jun 19, 2006
    Oddometer:
    577
    Stu,
    You seem to be very knowledgeable. I'm a relatively new KLR owner in learning mode here. Thanks for your thoughts. As described in the post, I added the tab washer for extra safety. I have an avaiation background. We have special captive fastener requirements for non fail-safe requirements. These requirements are outlined in the "FAR's". FAR 25.607 requires that each removable fastener have two separate locking devices if loss of the fastener could prevent continued safe flight and landing or if its loss would materially degrade the controllability of the airplane. So, if the drive sprocket nut un-threads, while at high speed, could this lead to loss of bike control? Most likely. Therefore, I added the tab washer for safety. It consumed about 30 seconds of effort. Adding the tab washer is not absolutely necessary, however I do not find it "silly".
    Keithm
    #16
  17. CA Stu

    CA Stu Master of air potatofication Super Moderator

    Joined:
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    What are the torque specs for the heads on an airplane?

    They are just as irrelevant to your KLR as the FAR you quoted. :D

    I have owned KLRs for almost 9 years now, have been active in several online forums and attended numerous Tech Days and rallies, and have never, ever heard of a countershaft nut coming loose at speed. Have you tried to remove the front sprocket without loosening the chain? It's physically not possible.
    Add the sprocket cover, it's also a physical barrier, there's your "belt and suspenders".

    Maybe "silly" wasn't the best choice of words, and I apologize.
    "Redundant and pointless" would have been better.

    I can respect your airplane mechanic's knowledge and experience. Can you respect my KLR mechanic's knowledge and experience?

    Thansk
    CA Stu

    PS The fact you were using the shim washers from a different year to alleviate a problem that Kawasaki eliminated in 1996 is kind of a tip off that you are totally clueless about KLR mechanics.
    #17
  18. CA Stu

    CA Stu Master of air potatofication Super Moderator

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    Would you please explain exactly how a splined sprocket (with no threads) can "unthread", too? :ear

    Thanks
    CA Stu
    #18
  19. larryboy

    larryboy Chopper Rider

    Joined:
    Jan 9, 2005
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    18,202
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    Über Alles,California


    Don't worry about him, he's a total asshole and should go for a ride and stop his nitpicking.

    Us morons that thrash our KLR's understand why you shimmed from the back to center the sprocket. Using the locking washer is overkill, but it's your bike..do what you want. It's actually needed since you put it on and lost a little thread engagement on the nut, personally I'd pull it and toss it.
    #19
  20. CA Stu

    CA Stu Master of air potatofication Super Moderator

    Joined:
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    Hi Larry!

    I am one of those morons (it was a joke, man), I have ridden my KLR on the AMA LA-B-V ride 5 times.

    The last 4 times with a 14t sprocket.

    And thanks for the ad hominem attack!

    Thanks
    CA Stu
    #20