CRF 450R 2008 Piston stuck
  • Charlesvw
    Posts: 1
    Joined: Mon Feb 18, 2019 10:31 pm

    CRF 450R 2008 Piston stuck

    by Charlesvw » Tue May 14, 2019 10:25 pm

    Hi Everyone
    I bought my first bike about 3 months ago and put about 10 hours on it. The guy I bought it from had the piston replaced, crank shaft bearings with new crankshaft connecting rod bearings with new connecting rod, and it was all done by Honda. This was 30hours ago.
    Now two weekend ago we where out riding and only about 20 mins in I was in 5th gear flat out when I felt the bike losing power so I geared down and it got worse until the motor locked and back wheel dragging along. I took the the bike to Honda as they where the ones that worked on it not to long ago. They recon it is because the bike's oil level wast correct or bike was over heating and piston melted. But from my limited knowledge this is clearly an impact on the piston as it is one side of the piston bent and as I can see to the head on the exhaust valves side the impact was there. So what I think happened maybe when they replaced the connecting rod they tightened it to much and the bearing collapsed and that is what caused the piston to have the extra travel to hit the head?
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  • User avatar
    Posts: 3658
    Joined: Sat Nov 25, 2006 6:31 pm

    Re: CRF 450R 2008 Piston stuck

    by JimDirt » Wed May 15, 2019 9:24 am

    Welcome to the site !! \:D/

    From what I can see in the pictures , it looks like the skirt is missing/broke on the one side , this would cause the piston to cock sideways in the cylinder as the skirt is very short to begin with , this would lead to the piston being shoved sideways and hitting the head as you have seen , the most likely cause from this would be a frozen wrist pin , I would think , the reason for it freezing could be any number of reasons , from lack of oil to improper installation , if the wrist pin is blue , it would suggest heat caused by lack of oiling , most likely the wrist pin bearing would have similar signs

    Saying this is the dealers responsibility , is going to be hard to determine , as lack of oil could cause it , or a installation issue ...... I would ask the dealer if they would be willing to split the bill , since its going to be really hard to pinpoint the cause , unless you have some physical evidence of improper installation , like a missing C-Clip for the pin , or something , or that the piston was installed backwards or something ..... the other alternative is to convey to them , that (this is providing there is no evidence of such) that if the engine had a lack of oil it would also have done damage to the cam bearings/lobes , as well as main bearings , etc , if there is no evidence of that , then it is unlikely that it was a oil starvation issue as they are claiming .... and if it fact that is the case , then they should cover all parts and labor .... but again , you need to show evidence that is the case ......
    02 CRF450R
    06 CRF450X
    Weiser , Idaho
  • Aussiecrf230
    Posts: 1671
    Joined: Fri Jan 06, 2006 11:11 pm

    Re: CRF 450R 2008 Piston stuck

    by Aussiecrf230 » Thu May 16, 2019 12:28 am

    Sorry to see the results of your troubles.
    Have to agree that it lost a skirt on the piston and rotated hit the head and valves. Doubt it was reversed piston as there would be more damage to top of the piston and inlet valves.
    Did you check the oil before the ride and after you had trouble?
    Do the insides of the cases smell like burnt oil?

    Be interesting if you could post up a picture of the bore and the piston skirt.
    Was the broken bit of skirt found?

    If the bore and skirts don't show any pickup or scoring then it wasn't heat and maybe not oil. The little end condition will be a tell tale as Jim said.

    CRF230F 2004
    C30F Power Up needle
    Mains 132
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    Baffle out, Screens In

    It starts,it runs,it gets to where all CRFs can get to without the valve or valve plate dramas
  • Back2-2
    Posts: 879
    Joined: Tue Jan 04, 2011 3:31 pm

    Re: CRF 450R 2008 Piston stuck

    by Back2-2 » Thu May 16, 2019 11:27 am

    That there is one of the nastiest top end wipe outs I have seen on a 4 stroke. Looks to me like it was piston slop that was the problem not lack of oil. Lack of oil causes over temp and seizing but the piston stays square to the bore and seizes in place. Its obviously hard to tell from a couple pictures and more investigation to the connecting road and crank will tell the story. I have seen piston skirts bust off but they usually get down into the crank and jam up.
    But damn, that is a bad one. :shock:
    Black Hills of SD
    Life without Motorcycles would just be boring, really boring

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