New help with replacment SS valves & piston crf250r
  • Krazy Kev
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    Joined: Mon Feb 02, 2009 1:17 pm

    New help with replacment SS valves & piston crf250r

    by Krazy Kev » Mon Feb 02, 2009 1:37 pm

    I need to replace my 2004 CRF250R piston.
    Any advice from the Gurus out there? I could use some step by step instructions, only done this on a 2-stroke.

    Also looking for some advice on valve replacment. My local shop says I can replace with stock vales and don't need any head work. But if I go to SS valves that I will need to have the seats ground?!? Do I need head work or not? if so where do I take the head?

    I have purchased Faction stainless valves, springs, stems, seals & Pro X piston.

    Thanks
    Krazy Kev
  • Ready2Close
    Posts: 82
    Joined: Thu Nov 27, 2008 6:44 am

    by Ready2Close » Mon Feb 02, 2009 3:13 pm

    I just did exactly what you are preparing to do to my 06'crf250r.

    I went with the Kibblewhite stainlees steal intakes, took off my head and sent to ~. He did an exceptional job at a good price.

    Yes, the SS valves need to have the seats cut. You may be able to get away with the Titanium fitting just right, but I was looking for longevity in my valves.

    I also put an OEM piston kit it (did myself). Don't forget to put a new cam chain in and a new gasket kit. I used the manual and got through it once I got the head back.

    Finally, when taking the head off you are going to need to release the cam chain tensioner. You can use a small thin flat head screw driver, turn it to release and then use a pair of vice grips to hold it in place. Aside from this little tricky part you should be good to go.
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    amaviper
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    by amaviper » Mon Feb 02, 2009 7:14 pm

    You need to cut the seats everytime you replace the valves and make sure the guides are true. Titanium or Stainless. Cupped valves mess up the seats.
    '06 CRF450X; '07 CRF230F; '03 CRF230F; '03 XR100R; '03 XR70F; '79 KZ1300 A-1; '71 SL350 K1
  • Krazy Kev
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    Joined: Mon Feb 02, 2009 1:17 pm

    by Krazy Kev » Tue Feb 03, 2009 8:45 am

    amaviper wrote:You need to cut the seats everytime you replace the valves and make sure the guides are true. Titanium or Stainless. Cupped valves mess up the seats.


    Thanks
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    logan6437
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    Joined: Wed Mar 04, 2009 12:07 pm

    by logan6437 » Thu Mar 05, 2009 12:03 pm

    my input from working in a honda shop, you always want to get the head ground even if its just a little, just do not use valve grinding compound it does not have lasting effects stainless valves are ok for budget replacement, titanium let your engine rev easier as being titanium has reduced weight, both last about the same titanium valves has a coating to help reduce wear, best bet for replacing the piston is to get a manual for step by step instructions, its really not a hard job if you know your way around a tool box at all it is fairly easy just dont do shortcuts, take your time and double check
    "Who ever said nothing was impossible never tried slamming a revolving door"
    "Chuck Norris can kill two stones with one bird."
    "In the bible Jesus turned water into wine, Chuck Norris turned that wine into beer"
    2004 crf450r
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    124
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    Joined: Wed Feb 16, 2005 1:37 pm

    by 124 » Thu Mar 05, 2009 12:45 pm

    logan6437 wrote:my input from working in a honda shop, you always want to get the head ground even if its just a little, just do not use valve grinding compound it does not have lasting effects stainless valves are ok for budget replacement, titanium let your engine rev easier as being titanium has reduced weight, both last about the same titanium valves has a coating to help reduce wear, best bet for replacing the piston is to get a manual for step by step instructions, its really not a hard job if you know your way around a tool box at all it is fairly easy just dont do shortcuts, take your time and double check


    Correct and incorrect sir. It is true that should cut the seats everytime you replace the valves. Cupping and pitting occur in the valve-to-seat relationship during use. You cannot use valve lapping compound with titanium, you can with stainless.

    Stainless valves are not budgetary. They cost more due to the fact you must use heavier springs. More mass = more inertia = heavier spring needed. BUT, stainless valves with proper headwork will last multiple times longer than titanium equivalents. The coating on the Ti valve wears out creating these issues.

    It is true there is a slight loss in revs, but I've yet to meet anyone that noticed a difference. C-riders to A-riders included.

    I also recommend ~ for the headwork.
    70' Honda CT70 (Trail 70; Gold)
    06' Honda CRF50
    00' Honda XR80R
    04' KTM 50 Pro-Senior LC
    11' KX450
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    Orange Squishy
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    by Orange Squishy » Thu Mar 05, 2009 2:11 pm

    124 wrote:BUT, stainless valves with proper headwork will last multiple times longer than titanium equivalents.


    Hey 124, I remember you saying you got a couple of seasons out of SS some time back when I was doing my head. Out of curiosity what's your latest valve status/history?
    2005 Honda CRF250R
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    124
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    Joined: Wed Feb 16, 2005 1:37 pm

    by 124 » Fri Mar 06, 2009 5:39 am

    Orange Squishy wrote:
    124 wrote:BUT, stainless valves with proper headwork will last multiple times longer than titanium equivalents.


    Hey 124, I remember you saying you got a couple of seasons out of SS some time back when I was doing my head. Out of curiosity what's your latest valve status/history?


    I made it about 2-1/2 seasons out of my SS. I shimmed for the first time in Dec of 08' before some arenacross practice over this past winter. I haven't ridden in a month or so. I purchased the KW intake kit from CRF's. Hopefully next week my head and bag-o-parts will be on its way to California for a visit with ~. I wanted to do it last month, but I had to put a dent into my "secret motorcycle repair stash money"... :lol:
    70' Honda CT70 (Trail 70; Gold)
    06' Honda CRF50
    00' Honda XR80R
    04' KTM 50 Pro-Senior LC
    11' KX450
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    logan6437
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    Joined: Wed Mar 04, 2009 12:07 pm

    by logan6437 » Fri Mar 06, 2009 7:16 pm

    124 wrote:
    Orange Squishy wrote:
    124 wrote:BUT, stainless valves with proper headwork will last multiple times longer than titanium equivalents.


    Hey 124, I remember you saying you got a couple of seasons out of SS some time back when I was doing my head. Out of curiosity what's your latest valve status/history?


    I made it about 2-1/2 seasons out of my SS. I shimmed for the first time in Dec of 08' before some arenacross practice over this past winter. I haven't ridden in a month or so. I purchased the KW intake kit from CRF's. Hopefully next week my head and bag-o-parts will be on its way to California for a visit with ~. I wanted to do it last month, but I had to put a dent into my "secret motorcycle repair stash money"... :lol:




    everyone has different sercumstanses in my book i just remember at the shop they were about even with wear it all depended on maintenance the customers took, when i bought my titanium valves they were more expensive then the stainless, maybe they muffed up at the counter idk.
    "Who ever said nothing was impossible never tried slamming a revolving door"
    "Chuck Norris can kill two stones with one bird."
    "In the bible Jesus turned water into wine, Chuck Norris turned that wine into beer"
    2004 crf450r

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