04 CRF250R engine rattle, help appreciated
  • spacefone
    Posts: 3
    Joined: Mon May 14, 2018 7:17 pm

    04 CRF250R engine rattle, help appreciated

    by spacefone » Mon May 14, 2018 7:19 pm

    So I got a bike that had been sitting in the garage for years running again and heard a rattle in the engine, but reading up on it I saw some people online say the 04's have a "noisy top end". I chalked it up to that as it gave me some piece of mind.

    Fast forward to this week and I'm at the track and a couple of guys I'd been talking to brought the noise up. One guy said it's the piston rings and another said that would never cause a rattle and that it's valves.

    So here I am reddit, can you help me figure out what this rattle is before I go blowin' up an engine that looks to have very low hours on it

    here's a video so you can listen for yourself. The exhaust kind of resonated in the garage which makes the rattle seem a bit quieter than it really is.

  • spacefone
    Posts: 3
    Joined: Mon May 14, 2018 7:17 pm

    Re: 04 CRF250R engine rattle, help appreciated

    by spacefone » Mon May 14, 2018 7:30 pm

    Disregard me addressing reddit, copying and pasting doesn't always go as planned
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    JimDirt
    Posts: 4406
    Joined: Sat Nov 25, 2006 6:31 pm

    Re: 04 CRF250R engine rattle, help appreciated

    by JimDirt » Tue May 15, 2018 11:54 am

    Welcome to the site !! \:D/

    It sounds like a Timing Chain rattle to me , i would be looking at either a stretched timing chain , or the Tensioner going bad

    It could also be piston slap , if the bike has a lot of hours on it , the piston could be worn and rocking side to side in the cylinder , which can lead to the piston skirt breaking and causing cylinder damage , if the bike has been ridden a lot and then sat (I am assuming you recently purchased this bike , or has it been yours and it just has been sitting ?? , if so how many hours do you estimate are on it ?? ) ,if it was recently purchased , its possible it sat because it was getting time for a rebuild and the prior owner was putting it off or did not want the expense , , so it might be a good time to do a quick rebuild , replacing the piston/rings , and timing chain and tensioner , doing it yourself you can get away with a few hundred bucks and your back riding , if the valves have been replaced you should be good with them for a while , if not check the lash , if it is tight then i would also recommend doing a valve job , once all that is done you will have a fresh engine that will last several riding seasons depending on how its ridden ...... I track ride my 02 CRF450R and i get several seasons out of the engine before a rebuild is needed , i currently have 2 full seasons on it on the same piston/rings/timing chain , etc.. ....
    2020 CRF450R
    2006 CRF450X
    Image
    Weiser , Idaho
  • spacefone
    Posts: 3
    Joined: Mon May 14, 2018 7:17 pm

    Re: 04 CRF250R engine rattle, help appreciated

    by spacefone » Tue May 15, 2018 9:47 pm

    Thanks so much! There's hardly any boot wear on the case so I'm guessing the hours are pretty low. The bike was purchased many years ago and has been collecting dust until now.

    By lash you do mean valve clearance right? If so, they are way out of spec on the tight side. Would that require valve/spring replacement, or just adjustment?

    I'll pick up a piston/rings and just get that out of the way if i'm already going to be in there anyways.

    Again, thanks for your reply as it's been very helpful
  • User avatar
    JimDirt
    Posts: 4406
    Joined: Sat Nov 25, 2006 6:31 pm

    Re: 04 CRF250R engine rattle, help appreciated

    by JimDirt » Thu May 17, 2018 7:50 am

    Thanks so much! There's hardly any boot wear on the case so I'm guessing the hours are pretty low. The bike was purchased many years ago and has been collecting dust until now.

    By lash you do mean valve clearance right? If so, they are way out of spec on the tight side. Would that require valve/spring replacement, or just adjustment?

    I'll pick up a piston/rings and just get that out of the way if i'm already going to be in there anyways.

    Again, thanks for your reply as it's been very helpful

    Yes by lash i am talking about Valve Clearance , generally once they start going out of adjustment , its only a matter of time (sometimes only a few rides) till the valves "zero out" which means you will not find a small enough shim to "adjust" the valve clearance , which means the valve face is worn or cupped and the valve seat in the head itself will need to be re-cut or replaced depending on the damage/wear done , (basically you need a valve job) , if your not "racing" at a professional level where every ounce of weight is saved , you can switch to Stainless intakes , and your valve maintenance will be mostly non existent , i race my 450R with Stainless Intakes with no issue , you just need matching valve springs for the Stainless valves as they are heavier than Titanium and need stiffer springs (Ken , the owner here does valves , his work is excellent and his prices are very reasonable especially compared to big name places like Pro Circuit , etc , and his work is on par with them , and he has a very quick turn around
    , so you will be back up and riding in no time) https://www.crfsonly.com/catalog/index.php/cPath/258

    And yes , doing the valves now while your tearing it down would be the best time , then you will have the rest of the riding season (which is just underway) to enjoy riding
    2020 CRF450R
    2006 CRF450X
    Image
    Weiser , Idaho

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