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Thread: Grind 'em?

  1. #1
    Join Date
    Mar 2003
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    Grind 'em?

    Clymer states that the valves in the honda atc engines are specially coated and failure WILL result if it is removed. This has been challenged in another thread. So, how many of you have succesfully ground their valves? The specific engine I'm interested in is an 82 200.

  2. #2
    Howdy's Avatar
    Howdy is offline Putting Priorities in Order, Busier than ever. Catch me if you can
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    I have ground the valves in a couple machines and never had a single problem. The one motor was out of a Late Model 125m ( it has a atc200 head on it ). This motor was put into a 1988 TRX125 ( The Wrecker ) and has been running good for over 5 years. I did the valves in my 350x also and it runs like a top also. It was done 2 years ago.

    So, I personally don't think there would be a problem.
    Has anyone else ground their valves?
    Howdy

  3. #3
    Join Date
    Nov 2002
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    Kirkville, NY
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    Bought new valves for my last 200s and ground them in, no problems. I have reseated the old valves in my friends 200s and several yamahas and have not had any problems with them so far.
    1984 Yamaha YT 60 Tri Zinger(current project)
    1983 Yamaha YTM 200 (rear suspension kit)..... long term project
    2004 BMW R1150R
    1972 Honda CT 70
    2007 Lifan 110

  4. #4
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    Nov 2001
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    I do believe that what the manual is trying to tell you is in the event the valve tip is mushroomed do not grind it smooth. That is the end that is specially heat treated. The large valve head is always servicable, so grind/lap away!
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  5. #5
    bbechtel16 is offline At The Back Of The Pack Arm chair racerAt the back of the pack
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    I don't know much about internal engine work, but I don't think them refering to the tip would make any sense because then the cams/rockers wouldn't open the valves as far? Anyone follow me and agree/disagree?
    -'86 ATC 250SX: No longer mine... Complete 350X front end, Corbra Megaphone system, 350X carb with UNI dual stage foam & outerwear bolted driectly up, Powroll/Rocky 260cc bore 10.5 to 1 compression piston.

  6. #6
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    Even if it were ok to grind the tip, the adjusters would take up the slack. Your lift is determined by the cam, and any geometrical lift lost from the different rocker angle is extremely negligible.
    Again the tip is hardened, and any grinding there will seriously impair the rocker to valve durability.
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  7. #7
    bbechtel16 is offline At The Back Of The Pack Arm chair racerAt the back of the pack
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    Ohhhhh, I get it now... If you ground the valve tip when you adjusted the valve clearance that would take up the space is what you're saying?
    -'86 ATC 250SX: No longer mine... Complete 350X front end, Corbra Megaphone system, 350X carb with UNI dual stage foam & outerwear bolted driectly up, Powroll/Rocky 260cc bore 10.5 to 1 compression piston.

  8. #8
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    Yes, but DO NOT grind the tip and reuse! It has been heat treated for long life. With that surface removed, it will wear almost instantly. The manual recommends grinding only to remove the mushroomed end to remove it from the head.
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  9. #9
    Join Date
    Jan 2003
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    What does grinding the valves mean?

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