2004 crf450r doesn't stay in TDC
  • crfnovice123
    Posts: 2
    Joined: Tue May 16, 2017 11:19 am

    2004 crf450r doesn't stay in TDC

    by crfnovice123 » Tue May 16, 2017 11:33 am

    I just re shimmed my valves following the guideline in the manual and then following along with several videos at the same time. The bike will not start now. I have checked and re-checked my measurements while the bike is in TDC and the gaps are all withing spec.
    Here is what i know:
    I am getting a spark
    The kick start is very stiff
    When I have Tdc showing on both the upper flywheel and the lower crank (right clutch side) and then manually turn the lower crank clockwise using an Allen wrench stuck in the clutch side the fly wheel will turn with the chain partially then stop, not returning to TDC when the crank I am turning does.
    I have no idea why this is doing this but I would really like to get this issue resolved so I can start riding again.
    Any advice?
  • User avatar
    JimDirt
    Posts: 4406
    Joined: Sat Nov 25, 2006 6:31 pm

    Re: 2004 crf450r doesn't stay in TDC

    by JimDirt » Tue May 16, 2017 6:45 pm

    Welcome to the site !! \:D/

    It sounds like you might have a few things going on here , it sounds like the timing chain adjuster is either allowing slack in the chain , or you might have it a tooth off , you did not mention the slash marks on the cam gear , as they should be even with the head as well at the same time the other 2 marks are aligned , so like - - for the cam gear marks , along with the other 2 marks aligned , generally the kicking should be somewhat easy , so you may have the de-compressor gap too loose which would account for the hard to kick issue even 2mm difference will make a difference in how easily or hard it kicks

    With the timing , with the cam facing the rear (2 O'clock position looking from the left/ignition side) and the cam gear marks level with the head , you should be able to look in the small plug on the ignition side and see the mark , you should also be able to see the arrow/dot on the clutch side 2" round plug , all aligned at the same time , if not , then it has to be either a stretched timing chain or a issue with the tensioner , or when you assembled the cam you got it a tooth off on the chain and when the chain is on the mark on the cam , the others are off , the clutch side and ignition side should be aligned automatically due to the gears being connected thru the balancer shaft , so the main culprit would be the cam installation , or a issue with the tensioner and/or chain stretched
    2020 CRF450R
    2006 CRF450X
    Image
    Weiser , Idaho
  • crfnovice123
    Posts: 2
    Joined: Tue May 16, 2017 11:19 am

    Re: 2004 crf450r doesn't stay in TDC

    by crfnovice123 » Sat May 20, 2017 5:37 pm

    It looks like the issue is the timing chain keeps coming off the fly wheel, once I am able to get the chain back on the fly wheel, I just have to say a prayer, and then keep a little tension on the chain while I get it on the top end and reassemble the bike. That is the theory at least. There has got to be a better way to keep the chain on the fly wheel though while the chain has slack.
    Thanks for all the help and advice.
  • User avatar
    JimDirt
    Posts: 4406
    Joined: Sat Nov 25, 2006 6:31 pm

    Re: 2004 crf450r doesn't stay in TDC

    by JimDirt » Sun May 21, 2017 10:44 pm

    When i remove a cam , i put a string around the chain or wire thru one of the links (metal coat hanger or bailing wire) , and tie it off to the frame spar , that way its out of the way , but keep the tension on it , then when i get the cam back in and put the chain on it , and then put the tensioner back in , that keeps it tight , if the chain is worn , it will have excessive slack , there "should" be a tab down by the crank gear bolted to the case that keeps the chain from falling off (its behind the flywheel) , its possible that it got bent down somehow if the engine got rotated with the chain slack and is allowing the chain to fall off the gear when its slack
    2020 CRF450R
    2006 CRF450X
    Image
    Weiser , Idaho

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