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  1. #1

    need replacement valves

    re doing top end did a cp big bore a few years ago been drinking oil ever since finally tore it apart and it looks really good other then intake valves are worn. What are good stock replacements stick to yamaha only or is there any others that are good? Checking everything over the only thing i see wrong that may cause it to use oil is it looks like the oil scrapers had way too much gap like .05-.06 the new rings cpn-4016 are different and the oil ring gap is good but now i have a nitrided top ring the cp kit came with ductile iron did cp do an update on the rings? The top and 2nd rings only have like an extra .002-.003 of gap since the first rebuild.

  2. #2
    Administrator WV Hot Rod Rhino's Avatar
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    Sounds like the ring gap is too big...top ring should be.018 and second ring .020

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    James Davis
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  3. #3
    Quote Originally Posted by WV Hot Rod Rhino View Post
    Sounds like the ring gap is too big...top ring should be.018 and second ring .020

    Sent from my Moto E (4) Plus using Tapatalk

    ring end gap on the top 2 rings isnt all bad i had gapped them when first put in and are sitting at .021/.024 now but its the oil scraper rings that have way too big of gaps.
    the new rings i got are diff then the ones that came with the piston my new rings have a nitrided top ring and a "j hook" 2nd cast one now where the ones that came with were both iron.

    The new oil scraper rings have .014" gap i think i remember checking the originals and all it said was .015min but do not file and it had more so i just figured they were right

    found some new yamaha valves not far from me

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