CRF450X Starting Issues
  • OneWound
    Posts: 28
    Joined: Fri Nov 10, 2017 4:09 pm

    Re: CRF450X Starting Issues

    by OneWound » Mon Nov 26, 2018 7:44 pm

    To WRT to the images, it was one link with four photos within that link. Lesson learned!

    Anyways,

    I ran my hand over the grooves on the piston and the cylinder wall and they felt smooth. When I ran my fingernail over the cylinder wall, it felt rough (but that makes sense... cause don't you want the cylinder wall to be rough?). The roughness did feel consistent, however.

    I'll order a new piston (Wiseco with a 13:5 compression rating, adherant to the box I found). I am curious - what did you see that drove the piston change? Was it the ridges? (I'm asking because the assumed OEM piston had the same ridges, but further up).

    Finally, I'll order a new timing change. Shesh! ;)

    Also, final question. With this brand-spanking-awesome-piston, I should be able to put close to 2k Miles on it before I have to change it, correct? (I'm asking because ideally - I'd like to do some pre-runs and make sure the bike is reliable before I make my great race)
  • Aussiecrf230
    Posts: 1587
    Joined: Fri Jan 06, 2006 11:11 pm

    Re: CRF450X Starting Issues

    by Aussiecrf230 » Mon Nov 26, 2018 8:30 pm

    Use some wd40 or the like with the scotch brite to help remove carbon from the cylinder cross hatch. It will probably look brand new then
    Ray
    Australia

    CRF230F 2004
    C30F Power Up needle
    Mains 132
    Idle 45
    2 turns out
    Baffle out, Screens In

    It starts,it runs,it gets to where all CRFs can get to without the valve or valve plate dramas
  • User avatar
    JimDirt
    Posts: 3419
    Joined: Sat Nov 25, 2006 6:31 pm

    Re: CRF450X Starting Issues

    by JimDirt » Tue Nov 27, 2018 8:27 am

    To WRT to the images, it was one link with four photos within that link. Lesson learned!

    Anyways,

    I ran my hand over the grooves on the piston and the cylinder wall and they felt smooth. When I ran my fingernail over the cylinder wall, it felt rough (but that makes sense... cause don't you want the cylinder wall to be rough?). The roughness did feel consistent, however.

    I'll order a new piston (Wiseco with a 13:5 compression rating, adherant to the box I found). I am curious - what did you see that drove the piston change? Was it the ridges? (I'm asking because the assumed OEM piston had the same ridges, but further up).

    Finally, I'll order a new timing change. Shesh! ;)

    Also, final question. With this brand-spanking-awesome-piston, I should be able to put close to 2k Miles on it before I have to change it, correct? (I'm asking because ideally - I'd like to do some pre-runs and make sure the bike is reliable before I make my great race)
    Yea with IMGUR , go to the picture and click , then when the image opens you see the links to the right , use the second to last code (near bottom) that says BBCode (message boards & forums) , copy and paste each link (paste , then hit ENTER then paste the next link right below the prior) do that with each picture , as I posted in my example and it will show up fine

    What I saw on the skirt was the wear , you notice the grooving and patterned part of the skirt , that is a Teflon coating , when it wears thru , the piston will have side to side slop , in other words the piston can rock back and forth while going up/down in the cylinder , possibly leading to the skirt breaking and causing all sorts of havoc inside the engine , basically when the skirt is showing signs of wear (even less than what showed in your picture) then its time to replace the piston , you will note on the new piston , it will have a nicely coated skirt (the same Teflon in your frying pans , so you know when it wears the food sticks and the pan does not work as well , same goes for the piston) , not to mention that layer that is now worn off , now makes the gap between the piston and cylinder larger , so it contributes to side to side slop , and oil blow by , as well as compression loss , as well as rattling , put your hand inside a drink pitcher , then bang your hand around inside the pitcher , that is what the piston is doing in the cylinder....

    This is a worn piston on the left and new on right (same piston) , notice the difference in the wear on the skirt , yours looks much worse than that
    Image

    I would not see any reason why you could not put a few thousand miles on the new piston , if you keep the oil clean , and don't bounce the engine off the rev limiter , and don't allow it to overheat , it should last thru your riding adventure and then some .... , I track ride one of my bikes and get 2-3 seasons out of a piston , its all about keeping the inside of the engine clean (make sure your air filter is always clean , and oiled properly , you do not want to see dirt on the inside of the airbox snorkel on the inside boot towards the carb , past the filter , this is what scratches pistons , and takes out your valves real quick) ;)

    And yes , any time you tear the top end down , its good practice to replace the Timing Chain , they are relatively inexpensive , and they do stretch just like a drive chain does , so when doing a tear down , make that part of your "maintenance" .........
    02 CRF450R
    06 CRF450X
    Image
    Weiser , Idaho
  • OneWound
    Posts: 28
    Joined: Fri Nov 10, 2017 4:09 pm

    Re: CRF450X Starting Issues

    by OneWound » Tue Nov 27, 2018 7:46 pm

    To WRT to the images, it was one link with four photos within that link. Lesson learned!

    Anyways,

    I ran my hand over the grooves on the piston and the cylinder wall and they felt smooth. When I ran my fingernail over the cylinder wall, it felt rough (but that makes sense... cause don't you want the cylinder wall to be rough?). The roughness did feel consistent, however.

    I'll order a new piston (Wiseco with a 13:5 compression rating, adherant to the box I found). I am curious - what did you see that drove the piston change? Was it the ridges? (I'm asking because the assumed OEM piston had the same ridges, but further up).

    Finally, I'll order a new timing change. Shesh! ;)

    Also, final question. With this brand-spanking-awesome-piston, I should be able to put close to 2k Miles on it before I have to change it, correct? (I'm asking because ideally - I'd like to do some pre-runs and make sure the bike is reliable before I make my great race)
    Yea with IMGUR , go to the picture and click , then when the image opens you see the links to the right , use the second to last code (near bottom) that says BBCode (message boards & forums) , copy and paste each link (paste , then hit ENTER then paste the next link right below the prior) do that with each picture , as I posted in my example and it will show up fine

    What I saw on the skirt was the wear , you notice the grooving and patterned part of the skirt , that is a Teflon coating , when it wears thru , the piston will have side to side slop , in other words the piston can rock back and forth while going up/down in the cylinder , possibly leading to the skirt breaking and causing all sorts of havoc inside the engine , basically when the skirt is showing signs of wear (even less than what showed in your picture) then its time to replace the piston , you will note on the new piston , it will have a nicely coated skirt (the same Teflon in your frying pans , so you know when it wears the food sticks and the pan does not work as well , same goes for the piston) , not to mention that layer that is now worn off , now makes the gap between the piston and cylinder larger , so it contributes to side to side slop , and oil blow by , as well as compression loss , as well as rattling , put your hand inside a drink pitcher , then bang your hand around inside the pitcher , that is what the piston is doing in the cylinder....

    This is a worn piston on the left and new on right (same piston) , notice the difference in the wear on the skirt , yours looks much worse than that
    Image

    I would not see any reason why you could not put a few thousand miles on the new piston , if you keep the oil clean , and don't bounce the engine off the rev limiter , and don't allow it to overheat , it should last thru your riding adventure and then some .... , I track ride one of my bikes and get 2-3 seasons out of a piston , its all about keeping the inside of the engine clean (make sure your air filter is always clean , and oiled properly , you do not want to see dirt on the inside of the airbox snorkel on the inside boot towards the carb , past the filter , this is what scratches pistons , and takes out your valves real quick) ;)

    And yes , any time you tear the top end down , its good practice to replace the Timing Chain , they are relatively inexpensive , and they do stretch just like a drive chain does , so when doing a tear down , make that part of your "maintenance" .........
    Final question before I wait for parts to arrive. Is there a good chance that the piston became very worn after just 500 miles of use (with my oil messup)? Or is there a good chance this is from the previous owner? Or is it hard to tell?
  • Aussiecrf230
    Posts: 1587
    Joined: Fri Jan 06, 2006 11:11 pm

    Re: CRF450X Starting Issues

    by Aussiecrf230 » Tue Nov 27, 2018 9:12 pm

    Looks like long term wear on the skirt, so think that issue is ok. The little end of the rod might have got some wear, but the skirt normally suffers if it binds. You normally replace the little end bearing anyway, so check the surface of the rod to be sure.
    Ray
    Australia

    CRF230F 2004
    C30F Power Up needle
    Mains 132
    Idle 45
    2 turns out
    Baffle out, Screens In

    It starts,it runs,it gets to where all CRFs can get to without the valve or valve plate dramas
  • User avatar
    JimDirt
    Posts: 3419
    Joined: Sat Nov 25, 2006 6:31 pm

    Re: CRF450X Starting Issues

    by JimDirt » Wed Nov 28, 2018 9:19 am

    Ray pretty much summed it up , it looks like long term wear ..... What I showed in the 2 piston picture is what "normal" wear looks like , yours seems to be extended long term or abusive/lack of regular maintenance wear .... basically , the piston was overdue for replacement .....
    02 CRF450R
    06 CRF450X
    Image
    Weiser , Idaho
  • OneWound
    Posts: 28
    Joined: Fri Nov 10, 2017 4:09 pm

    Re: CRF450X Starting Issues

    by OneWound » Fri Dec 21, 2018 3:32 pm

    Alrightly, well I am back trying to figure out what actually happened to this motor. I was replacing the timing chain and once I removed the flywheel - I found metal shards as below. Did the bearing from the rock arm exhaust go down into and shear the little panel thingy? I'm assuming I have to replace the flywheel - can the left side crank case (when all the metal shards are removed) be used as is?

    I see that that there are some lines (assumed stress fractures). Is this typical?





  • OneWound
    Posts: 28
    Joined: Fri Nov 10, 2017 4:09 pm

    Re: CRF450X Starting Issues

    by OneWound » Sun Dec 23, 2018 9:39 pm

    On second thought, is it a possibility to keep the fly while and just deburr the sharp edges? Or will the CG be that much offset from the amount of scrapes?
  • User avatar
    JimDirt
    Posts: 3419
    Joined: Sat Nov 25, 2006 6:31 pm

    Re: CRF450X Starting Issues

    by JimDirt » Mon Dec 24, 2018 4:57 pm

    Its really hard to tell in those pictures with those cracks , as sometimes there are casting imperfections that look like cracks , What you could do is get this kit , and check it yourself https://regismanufacturing.com/kwik-che ... gLRIvD_BwE

    It will help you find out if its just surface mold imperfections , or actual cracks , as far as the flywheel goes , I think if you just deburr the stuff that is sticking up and jaggad , you should be fine , the amount of material gouged out should not significantly affect the flywheel balance to where it would cause a failure or anything , so I think you would be just fine .... , It would be nice to know where all this material is originating from , and that you have found and removed it all ..... , something caused this to happen , you need to make sure it does not happen again , as it might end up catastrophic if there is something you missed and it lets go .... 8-[
    02 CRF450R
    06 CRF450X
    Image
    Weiser , Idaho
  • OneWound
    Posts: 28
    Joined: Fri Nov 10, 2017 4:09 pm

    Re: CRF450X Starting Issues

    by OneWound » Tue Dec 25, 2018 11:34 am

    So there’s a small tab that the non-bolted cam guide sits in (I tried to show it in the initial pictures; but I’ll try to get a better picture later). There’s enough of a tab left for the cam guide to sit on; however.

    My theory on why it broke is that some of the bearings from the exhaust rocker went down between the cam chain and the cam chain guide. From there; it was pinned by this shelf..and out of everything, the aluminum shelf sheared first. I found one or two bearings on the bottom of the left side crank case during initial disassembly.

    To clean it; I plan on flushing oil down the top and side and make sure there’s no more bearings or aluminum shavings. For the record; I haven’t found any aluminum in the oil.
  • OneWound
    Posts: 28
    Joined: Fri Nov 10, 2017 4:09 pm

    Re: CRF450X Starting Issues

    by OneWound » Sun Dec 30, 2018 9:48 pm

    As promised; attached are the photos for the cam chain guide and its broken pieces. While I had the bike apart; I poured some oil under the piston (and let it drain out) and no metally bits came out. As well, there were some small chunks in the crank case (and on the old timing chain!) but they have since been removed.

    I'm in the process of rebuilding the bike now.. the piston is replaced; rings are replaced; etc. In the process of replacing the rocker arm exhaust & cam (I hate those small retention rings).

    As an FYI, (and Jim, you may have alluded to this/previously mentioned this); I think the real cause is that the piston was very well-worn. This caused oil to get past the rings.. and burn up.. etc (I also did a little googling and other people said similar things). In addition, there are some burn marks on the bottom side of the piston (images also attached):

    Pic #1 of Cam Holder Tab


    Pic #2 of Cam Holder Tab


    Pic #3 Under the Old Piston


    Pic #4 Under the Old Piston
  • OneWound
    Posts: 28
    Joined: Fri Nov 10, 2017 4:09 pm

    Re: CRF450X Starting Issues

    by OneWound » Sun Jun 16, 2019 8:03 pm

    I suppose I'm due an update... since it IS 6 months later. Long story short, the bike runs now (and I only had to tear it back apart with the new piston once!) I do appreciate all the help; I apologize for the late update. The only hiccup I ran into re-assembling the bike was I somehow mistimed the bike; and it wouldn't run.. however that was a simple (albeit somewhat of a PITA fix).

    For those who really care, no the bike isn't fully running. I installed a Baja Designs headlight and now I'm dealing with new wiring gremlins \:D/

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