2008 crf 250 x starting issues
  • Abcooper
    Posts: 1
    Joined: Sat Apr 10, 2021 8:26 pm

    2008 crf 250 x starting issues

    by Abcooper » Sat Apr 10, 2021 9:11 pm

    So I have a 2008 crf250x and it is has been having a tough time starting up. Both electric start and kicking it are not working and I am having to bump start it every time. When I bump start it it works great! I’m confident it is the valves but I had the valves adjusted about 5 rides ago and it is already struggling again. My fear is the It needs a full top end rebuild but should i just get the valves adjusted again or could it be something else?
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    JimDirt
    Posts: 4406
    Joined: Sat Nov 25, 2006 6:31 pm

    Re: 2008 crf 250 x starting issues

    by JimDirt » Sun Apr 11, 2021 12:07 am

    Welcome to the site !! \:D/

    Was the reason for the valve adjustment because of the same symptoms ?? , if so , then most likely the valves are toast , the issue is , once they start moving , it is only a matter of time before they zero out again , once they get down to the point of a 1.25 shim , there is no more adjustment left , if they were recently adjusted and little time was put on , then they are at the limit and beyond adjustment , as the next adjustment is going to be less time than this last one , till it needs it again .... and as mentioned , once it gets to the point of no shim small enough , then you have no choice but to replace

    So I am guessing this is one of several valve adjustments that have been done , which is normal and leads to the eventual need for replacement .... depending on how much time/hours/miles you have on the bike , will determine what it needs for a "rebuild"

    If you have more than 150 or so hours , it most likely needs a piston , maybe sooner depending on how you ride it .... usually the valve wear is exacerbated by dirt getting past the air filter , usually via the seal where the filter goes up against the airbox opening , or sometimes thru the filter itself due to inadequate oiling , the best remedy for that is to keep the filter sealed and greased , or a heavier oiling and more frequent filter replacement/cleaning , I generally change my filters every ride , , my 450X was less than 6 months old when my Intakes went .... I replaced them with Stainless (in 2006) and have not had to adjust them since

    So to summarize :

    Piston is dependant on how the bike was ridden , revved , and maintained ... mileage may vary , some people change them every season , some change them every 100 or more hours , my 06 X is still on the original piston , and the compression is still within spec , my 2020 450R has 62 hours on it , I plan on a piston at 100 hours because I track ride it , and rev it to about 10,000+ rpm regularly ... if I did it per Manual schedule , it would be at every oil change or 15 hours ...I change my oil at 10 hours , and use full synthetic , and don't beat on it like a Pro racer would , so I can extend the maintenance schedule

    The thing you have to do , is do what you can , within your budget restraints , if you can afford a decent valve job (like the one's Ken does here) , plan on $500+ for the head (he even has exchange heads , where you send in yours , and he sends you a complete ready to bolt on head , so you don't have to wait for yours to be rebuilt) ,or you can go with a jiffy valve job and new (Stainless) intake valves , for about $150-$200 , which is basically someone (hopefully that knows what they are doing on these bikes) to cut the valve seats , and install the new valves ...... $150ish for a Piston and about $50-80 for Gaskets , about $30-$50 for a Timing Chain ... if you went complete rebuild , a new Crank will set you back $300+ .... then if you have someone else do all the work , then Labor on top of that , which could add up to a lot ... you can walk away with a couple hundred invested at minimum , or $1500+ , depending on how you approach this .... , that depends on your budget and what concerns you have , if you think the piston has tons of time , then yes , replace it , along with the timing chain , they go hand in hand .... if the bike felt like it had great compression till the valves started going , and you have not racked up tons of hours on the bike or abused it , then just do the valve job and ride till its time to do a piston ..... there are many variables here .... but at the very least , yes I would recommend replacing the valves .......... its time ...
    2020 CRF450R
    2006 CRF450X
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    Weiser , Idaho

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