How To: Crank Replacement Part 1
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    euromike_85
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    Joined: Tue Apr 29, 2008 10:24 am

    How To: Crank Replacement Part 1

    by euromike_85 » Sat Apr 18, 2009 7:05 pm

    Hey everybody, so i wasnt able to get a solid answer anywhere about my crank play problem so i gave in and bought a wiseco crank kit as well as a piston kit while im in there. just thought id let everyone know how i got about doing it. i know im gonna get a lot of yelling at for this but i DONT have a service manual, so hopefully ill do it right. please feel free to correct anything that i may have missed or did improperly. on a side note, the CRF compared to other bikes is actually quite accesible and forgiving to work on, even compared to some two strokes IMO. the disassembly (with patience) so far has gone quite smoothly, im looking forward to assembly.

    so first off here are some of the products i bought to do the job:
    Image

    iv got my crank kit, piston kit, clutch kit, timing chain, and some other things that arent detrimental to a bottom end rebuild.
    so hopefully ive got everything... unless i break something while dissassmbling :shock: , just have to be patient, so start stripping the bike down (plastics, muffler, gastank, subframe, and airbox, kickstarter lever, rear brake foot lever and drain the fluids.

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    clean the motor with engine cleaner and a tooth brush to get into tight places, i also had a vacuum cleaner handy to clean some dirt from recesses in the engine (spark plug hole etc...) so anyway, after it was relatively clean and the motor accesible i got to work taking off the right side engine cover (the cover on the clutch side). remove all the 8mm engine cover bolts and make sure that you get them ALL! dont force the case to "break free" it should come off with relative ease

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    as many of you allready know, this is the right side of the engine with the cover removed... what i noticed (and am not completely sure of) is the markings on the gear wheels, refer to next pic.

    Image

    Like i said, i dont have a service manual so i took special interest in this. correct me if im worng but it seemed to me that when the dimples on the inner gears (i think they have the same amount of teeth) line up, the motor is at TDC and the counter balancer shaft is at its lower position as in the pic below. what i was wondering is why there is a dimple on the second (smaller) gear on the crankshaft? (maybe just to line up to the case dimple in the case?) on the flywheel side its pretty simple to remove the cover just remember to unplug and free up the wireing that goes to the cover, and be mindful that the stator is mounted ON the cover itself. if a pic is required i can provide.

    Image

    anyway, so this is the position of the counterbalancer when the motor is at TDC and the dimples on the opposite side (of engine) gears line up.
    The next step was to get all the bolts and nuts loose on the crank gear, flywheel, sprocket, counterbalance shaft... I say "LOOSE" because i will remove them later on when i have the motor out of the frame (it prevents anything from unexpectedly falling out of place). unfortunately i dont have air, thus i dont have an impact wrench, but either the flywheel or crank shaft gear bolt can be loosend by putting a wrench on each one, and loosening one side while the other side is held. (it may happen that the fastener being held comes loose instead of the one your loosening, this is fine) however, once one of em breaks free then your gonna have to hold the shafts some other way, i used an old trick that worked in my 2stroke days. i put a piece of HARD wood inbetween the sprocket and swingarm, put the bike in gear and turn it over till it gets tight

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    then i put a wrench onto the fastener i wish to "break free" applying a fair bit of pressure onto the wrench but not forcing it furthur than necessary, I then tap the end of the wrench with a fairly big hammer (you need inertia) kinda like a cave mans impact wrench!

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    im not sure if this is a good method or not, but cant figure a better way when you dont have a clutch holding tool etc... ive used this method many times before and its always worked (of course you need to be patient and concentrate)

    Image

    all smiles so far. After loosening the crank shaft bolt, flywheel nut, counter balancer nut and drive sprocket bolt, i start to disassemble the clutch by removing the five clutch spring reatainer bolts, remove the clutch stack as a whole (its faster and more "hassle free" to remove the whole stack at once) carefule you dont lose the pressure plate thrust bearing on the end of the push rod. the pushrod and thrust bearing assy can now also be removed.

    Image

    the nut holding the clutch basket can be removed using the same method as stated above, Just be carefull not to strip the bolt as the previous owner did on my bike!!! (i needed a hand getting this loose, because a socket tends to buckle when you use only one hand. i needed a buddy to hammer on the end of the ratchet handle while i kept pressure on the nut and held the socket square to the clutch basket nut. otherwise i would have stripped the nut bare!!!) also NEVER re-use the locking washer just behind the nut (again to my dismay the previouse owner opted to reuse the washer which, thank god! didnt fail on me and trash my tranny!)
    once this is off you can disassemble the clutch assy. i left mine on for the time being.

    Image

    a tool which you MUST have when doing anything in the bottom end is a flywheel puller. its allways been important to have this tool in the past to prevent damage to the flywheel and crank, but its much more necessary on the CRF due to the integrated oil passage, seen on the end of the flywheel side crankshaft.

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    the flywheel puller hase a seperate part which screws over the oil jet so that the puller pushes on this "cap" and not the oil passage. mine required quite a bit of force to break free. once the flywheel is removed, begin to disassemble the head... refer to valve adjustment in the "HOW TO" section of these forums to get the cameshaft off. once your camshaft is off you can remove the cam chain from the engine.

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    at this point you may be wondering why we havent removed the motor... TRUST ME! getting the previousely mentioned fasteners off while the engine is on a bench is a chore even with the proper tools. keeping the engine in the frame assists in disassembly. with that said we can begin to remove the head. assuming that the airbox and subframe have been removed as previously mentioned, you can pull the carb "with boot" off of the head, then we can remove all cooling hoses from the motor.

    note: its not necessary to remove the radiators from the frame, but the U-shaped hose located at the bottom and connecting both radiators can get in the way of the exhaust bolt on the head.

    Image

    The engine stay mounted on the head can be removed and the 8mm bolts located on the cam chain side of the head and cylinder can also be removed. after these are removed you can loosen the four main Head nuts in a criss-cross patern.

    note: the reason i remove the 8mm bolts first is to prevent any extra pressure to act on them if the 4 main head bolts are released.

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    remove the head using a rubber mallet, and then the cylinder. i tried removing them both at the same time, in short... it doesnt work!

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    once the head and cylinder are off you can remove the drive sprocket (that we previously loosened) from the motor and then the whole motor itself from the frame. it would be a good idea to clean the motor AGAIN! please excuse my lazyness in not completely cleaning the motor.

    Image

    now like i said before, ive loosened the hard fasteners, they should come out nice and easy and you can lay each part out in the reverse order that they are assembled

    http://www.flickr.com/photos/37543534@N06/3453700843/

    i find that this way you have less of a chance of loosing track of parts. take off the clutch assy, crank drive gear(s) counterbalancer gear(s), kick starter spindle, kickstarter intermediate gear, and gear shifter shaft from the right side of motor. the counterbalancer is removed from the left side of the motor (take care when removing the balancer that you dont loose the plastic gear underneath it which is not held in place by any fasteners.

    once the motor is clean (once again i appologize for my sloppyness!) you can begin loosenging in a criss cross "ish" patern the 8mm engine bolts on the left side (there are no fasteners on the right side which hold the engine together. also remember to remove the tranny drain plug as well if you havent allready done so, as this also fastens both cases together.

    ive got to give a big shout out to user 124 who has provided dimensions for a rather usefull "bench" for supporting the motor. the dimensions are (inside width=140mm and inside length=324mm) made of 2x4. this helps alot when splitting the cases and working on the sides of the motor.

    Image

    placing the motor "right side DOWN" into the bench alows you to grasp the left side case. get a buddy to use a rubber malet to tap on the ends of the crankshaft and drive shaft while holding the motor suspended a bit over the bench so that your driving the right side case AWAY from the left side. DONT HIT HARD! the left side crank is on a cylindrical roller type bearing which slides easily. Rather tap evenly and alternate from crank to drive shaft depending on seperation gap.

    NOTE (IMPORTANT): if you are reusing the crank use the flywheel puller cap over the crankshaft end when hammering to prevent damage to the oil passage integrated into the crank.

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    The crank in my case came out of the right side bearing with little effort. if the crank is difficult to remove from the bearing, you can dissassembly the components on the right side case OR try overhanging the bench on a table. clamp the other end down so you dontdrop the motor on the floor. from underneath the bench use a rubber or brass mallet and drive the crank upwards. if it still wont go, use heat on the cases and bearing.

    Ok thats enough from me right now. its exactly 4:00 in the morning, ive been writting this all night so please excuse any errors. ill try and revise it in the future, part two has not been done yet. i have to install the new crank and then reassemble. i will then try and get it up ASAP
  • User avatar
    124
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    by 124 » Mon Apr 20, 2009 5:59 am

    What happened to the pics?
    Wat crank problem were you having that you couldn't get answers to?
    Where's Waldo?
    70' Honda CT70 (Trail 70; Gold)
    16' KX450
    16' KX85
    12' YZ125
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    euromike_85
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    by euromike_85 » Tue Apr 21, 2009 8:19 am

    hey there 124, i dont quite know what you mean about the pics. they show up on the page just fine for me. i had a question a while back about some vibration i was noticin in the foot pegs. naturally i thought crank so i went to open up the ignition side cover, once that was open and the chain tensioner released i noticed there was a tad of up and down play in the crank. i wanted (at the time) to change the main bearings but then i noticed that the inner race of the bearing is on he crank itself. fearing that the cranks race was worn, i purchase a brand new wiseco crank kit and decided to do the job just for good measure.

    Currently im about halfway through reassembly, im just waiting for the clutch basket lock washer to be ordered in then i can continue. meanwhile ive changed the piston, throttle cables chain guides and rollers, muffler packing. my clutch is still within spec (thickness wise) but my basket and inner hub is beginning to "teeth" :( but i have to wait until i get money for a new clutch...
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    124
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    by 124 » Tue Apr 21, 2009 10:18 am

    Hmmm...I can't see the pics. Must be an IT blockage of links of some sort from work. :-k

    Thats an interesting issue. I would assume that the bearing is worn and not the crank (inner race). The manual gives no specification (at least the 450R manual doesn't) on that feature of the crank.

    Sorry on the other post, I'm not sure how I missed it. Either way I think you're on the right track. Although, it may have been premature to buy a crankshaft right off the bat. I think only the bearing was worn. Let us know how it turns out.
    70' Honda CT70 (Trail 70; Gold)
    16' KX450
    16' KX85
    12' YZ125
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    euromike_85
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    by euromike_85 » Tue Apr 21, 2009 5:18 pm

    oh no worries about my previouse post, ive got the new crank in there and its solid, so at least i know it was a problem before. i dont know about the pics, i did want to share them. please let me know if you still cant see them at home? if not then ill try and post them on a different picture posting site
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    124
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    by 124 » Wed Apr 22, 2009 5:20 am

    euromike_85 wrote:please let me know if you still cant see them at home? if not then ill try and post them on a different picture posting site


    Ok...will do. Keep up the good work...
    70' Honda CT70 (Trail 70; Gold)
    16' KX450
    16' KX85
    12' YZ125
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    Lithium
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    by Lithium » Thu Apr 23, 2009 9:02 am

    Excellent write up euromike. Just got done doing this very same thing about a month ago. If you have any or all questions let me know.. but looks like you have a good handle on things.

    only thing I could suggest is saving up beer can money for a compressor and impact gun. Makes things go sooooooooooo much faster. That and make sure you set up the timing to the second mark on the flywheel when looking through the stator cover.

    looking forward to the update.
    Brandon
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    euromike_85
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    by euromike_85 » Sun Apr 26, 2009 11:44 am

    only thing I could suggest is saving up beer can money for a compressor and impact gun.


    LOL beer makes the job go EASIER! so it somewhat compensates :D no really your totally right, i was lucky that the nuts and bolts came off fairly easy, sometimes their a real pain :x especially the clutch basket nut! as for now im working on the reassembly, but i cut a bit of the plastic from the tensioner guide (black) while installing the cylinder head. so im gonna order one on monday. future note: install the tensioner guide AFTER the cylinder is installed.
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    Lithium
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    by Lithium » Sun Apr 26, 2009 1:50 pm

    Ohhh noo. well that sucks... but yeah the front one (white) sits down in the saddle and the back one goes on after the head and gets bolted in at the bottom as you well know now. Hopefully you will get your parts fast and hell at least now you know now that there isn't any wear on the back chain guide. :D

    While your waiting for parts you should look into getting a gear jammer http://www.crfsonly.com/catalog/product ... ts_id/2693

    It possible to go with out like I did but man this will REALLY save some time and head scratching when trying to figure out how to hold down the gears for re assembly. Especially when torquing down the primary gear.

    Best of luck.
    Brandon
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    euromike_85
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    by euromike_85 » Sun Apr 26, 2009 2:01 pm

    looks sweet, thanks for the input, but getting that purchased over here is near impossible. id have to get it off of e-bay and shipping takes about a 1-3 weeks, not to mention shipping costs duty and taxes :( i wish they'd get this stuff over here, um if its not too much to ask, i dont have the service manual for the bike, you wouldnt happen to know the torque specs for the flywheel, main gear, counterbalancer gear, clutch basket and sprocket? thanks in advance
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    Lithium
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    by Lithium » Sun Apr 26, 2009 2:52 pm

    Yeah no worries.

    Flywheel= 64Nm (47 lb ft)

    Main Gear= 108Nm (80 lb ft)

    Counter balancer= 44Nm (33 lb ft)

    Clutch Basket Center Nut= 69Nm (5l lb ft)

    Output Sprocket= 31Nm (23 lb ft)

    and while we are at it...

    Head nuts= 39nm (29 lb ft)

    Camshaft Caps= 16Nm (12 lb ft)

    That sucks about the wait time. Although you seem pretty handy with tools and aluminum is a cake to work with. If you have a saber saw, a file (mill basterd), marking pen and a piece of aluminum from the hardware store. A man could make a real nice one in a couple hours :idea:
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    euromike_85
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    by euromike_85 » Mon Apr 27, 2009 1:35 am

    Thanks a lot for the torque specs. if you'r ever in europe, get in touch and ill buy you a beer.

    A man could make a real nice one in a couple hours


    thats actually a good idea, i might try that, now only to get the dimensions somehow...
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    Lithium
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    by Lithium » Mon Apr 27, 2009 11:21 am

    Man Id love to check out Europe some day ill make it. Where in Europe are you at?

    As far as dimensions, Id try just tracing the teeth off the primary gear or counterbalancer gear and using that as a template.
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    euromike_85
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    by euromike_85 » Mon Apr 27, 2009 12:10 pm

    currently im living at my gf's house in a village right between vienna and bratislava, its central europe so you can reach a lot of great places fairly quick, prague, budapest, a bit furthur west you can get to germany or france. to the south you can get to italy fairly quickly (6 hours by car), and to the east, well, the former yugoslavia... which is OK, but havent visited often.
    oh yeah, and there are three motocross tracks just a couple of miles from where i live, one which i have yet to find but DOES exist! :D

    As far as dimensions, Id try just tracing the teeth off the primary gear or counterbalancer gear and using that as a template.


    again a great idea! so i should trace out the wedge between the main and counterbalancer? or the gear itself?

    thanks for the input by the way and heres a pic of whats holding me up for now:

    Image
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    Lithium
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    by Lithium » Mon Apr 27, 2009 1:00 pm

    wow your in a sweet spot. I looked it up on google maps and your smack dab in the middle. Man some day..

    Currently Ive got a E39 BMW540i with the sport package and the 6-speed and every time I drive it I think about how awesome it would be to roll on the autobahn. The fastest you can legally travel in the state of Oregon is 65 mph.

    Is there much for woods riding over there?

    As far as the jammer Id just trace the gear its self. That would probably be easiest. Then id cut out the template on card board and hold it in between the gears and see what it looks like. Then modify as needed. I would design it to engage at least 2 teeth fully on each gear. Probably over kill but better safe then sorry and since your fabricating it why not? :D

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