XR650R Valve Clearance Question

Discussion in 'Thumpers' started by MikesBikes90, Jan 26, 2020.

  1. MikesBikes90

    MikesBikes90 n00b

    Joined:
    Jan 26, 2020
    Oddometer:
    1
    Location:
    San Diego
    Hello,



    Quick question about valve clearance on my newly purchased '00 XRR. The previous owner uncorked it and put an XR's only competition exhaust on it but kept the stock header. As I was going over the basic maintenance on the bike I noticed the exhaust valves were way out of spec. This is my first bike with auto decompression, so I'm wondering if that has anything to do with it, or if uncorking/changing the exhaust caused the previous owner to alter the exhaust valves but not the intake???? or maybe its indicative of an engine problem that might require looking into.



    According to the manual I got, the intake should be set at 0.006 ±0.001 inches, and the exhaust should be at 0.008 ±0.001 inches.

    My intakes were set at a reasonable 0.005, but both exhaust valves were at 0.015, nearly double where they should be! In my limited experience, valves usually tighten up with use, not loosen up.



    I'm hoping somebody could shed some light on why they might be set so high. I took multiple measurements multiple times to ensure I was TDC on compression stroke, and tried my best not to let the flywheel rotate backwards. I'm planning on setting the valves to within spec, but thought I would ask in case there is some bike specific reason why they are so far out.



    Thanks guys,

    Mike

    P.S. sorry if I posted in the wrong spot!
    #1
  2. shardival

    shardival Been here awhile

    Joined:
    Jan 27, 2016
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    Poland
    Hi man!

    If both ex were out of spec I would say that they were set wrong and needs correct. Stick with your manual. Uncorking have nothing to valve clearance. Im not 100% sure, but even if you have stage1/2 cam installed, your valve clearance needs to be set as manual claims.
    #2
  3. BikePilot

    BikePilot Long timer

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    Golden CO
    Yep I agree, someone probably set them too loose. They do tend to tighten up, so I set them to the lose end of the factory spec.
    #3
  4. greasyfatman

    greasyfatman Long timer

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    #4
  5. KneltSpin

    KneltSpin n00b

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    Make sure you are actually at TDC and also that you removed decomp cable. If you don’t remove cable, that exhaust valve will be out of spec and clatter once you start it up.
    #5
    flybynite likes this.
  6. flybynite

    flybynite So far so good

    Joined:
    May 30, 2016
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    This.
    #6