Xr600 & xr650l aussie owners

Discussion in 'Australia' started by Kenno, May 30, 2013.

  1. GodSilla

    GodSilla I did that.

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    If the valves rotated and did as described, the bike would gain and lose power constantly. Compression-no compression-compression-no compression,......endlessly. This is not normal.

    It makes no sense unless there's some physical damage to something. I can kick mine over until the cows come home, it is the same compression every kick. Similarly, riding it there is no pulse of compression coming and going with the rotation of the valves. The description points to an underlying problem which may be the true cause of all the valve bending and camchain jumping, but who knows?

    One other thing to check. If you have raised the bars, the decomp cable can engage at full steering lock causing you to kick the piston into the valves. Worth checking.
  2. GSXR

    GSXR Trail Rider

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    Valves rotating doesn't cause any loss of compression. They are designed to do it as pointed out.

    Anyhoo.... Ron50 has provided what I consider the correct answer to bennos concerns.

    To add further... only use Jaso MA2 oil in your XR. It's on the bottle
  3. benno.h

    benno.h cageracer

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    Godsilla, I think we're saying the same thing, I just wasn't very clear earlier. Yes, compression does change exactly like that - push up to TDC (good compression) to get ready to start, decomp, sneak past TDC, give an almighty kick - nothing, and no compression for the next few kicks. A few more hard kicks and compression returns, and the cycle begins again.

    The valves *are* bent - I have the head off. They rotate in and out of positions where they seal - hence intermittent/variable compression. I can confirm this by shining a light at the bottom of the head and rotating the valves by hand.

    I don't have auto decomp or a cable for the manual decomp (home made lever down on the cylinder head).
  4. GodSilla

    GodSilla I did that.

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    :ear
  5. GodSilla

    GodSilla I did that.

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    No worries. I thought you were describing your fixed and running engine, my mistake.
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  6. GSXR

    GSXR Trail Rider

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    OK I'm out. In my 36 years engine building experience I've never seen a bent valve that will reseat itself with rotation. I'm also sure I never will. Then I read the bit about the home made lever and it's all coming together nicely. Keep it stock if you want to rock
  7. benno.h

    benno.h cageracer

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    Are you trying to say my decomp lever is causing these problems? Really can't see how that would happen.

    As for the valves, well they definitely seal better at some points when I rotate them by hand - I can see it. As to what happens when I kick, that's only my theory.

    Valve guides were checked last time I replaced the valves and the machinist re-surfaced the valve seats to match the new valves so I assume (dangerous, I know) that everything lined up as it should.
  8. lookfar

    lookfar from the land of OZ

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    Sounds like 4 new valves are needed.

    https://www.ebay.com.au/itm/New-Gen...0-Notes-W129/272213460200?hash=item3f612fc4e8

    https://www.ebay.com.au/itm/Genuine...m=361510007649&_trksid=p2047675.c100005.m1851
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  9. *perko

    *perko Adventurer

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    Perfect, makes a lot of sense now. I guessed I might have figured it out with everything pulled apart but always better to get the info straight from those who know.
    Very neat to have a way of disabling without removing and also keeping the kickback protection.

    There is definitely a lot of confusion as to how the whole system works, many people firmly believe it's black magic.
  10. lookfar

    lookfar from the land of OZ

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    Hey Benno, if you need a good head reconditioner, I use RPM Engines at Kunda Park (Maroochydore exit).

    They have done a few for me now, and also for a mate. Good value and really know their stuff.

    I have always supplied any parts that needed replacing when I dropped the job off.
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  11. Ron50

    Ron50 Been here awhile

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    I can see how it could appear that the valves are sealing better at one point of their rotation IF the guides are also bent/deformed. Definitely worth checking. Bending valve stems more than once would put a lot of strain on the guides and could lead to their moving in the head or having the through hole become oval.
  12. benno.h

    benno.h cageracer

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    Yeah, valve guides were inspected last time (I've been going to Serco at Woolloongabba) and were ok. I'm going to get some new valves and seat them and see what they look like - if they look like they seal up ok and I can rotate them without any obvious change in sealing I might not bother getting them professionally inspected.
  13. benno.h

    benno.h cageracer

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    Thanks mate, I'm actually referring to the spring on the outside of the rocker cover that returns the manual decomp lever to the normal position - the XR650L doesn't have manual decomp.
  14. lookfar

    lookfar from the land of OZ

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  15. benno.h

    benno.h cageracer

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    yeah... $60 is a lot for a spring! I've ordered one for an XR400. It's not quite the same but I'm hoping it might fit.
  16. lookfar

    lookfar from the land of OZ

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    NX650 head porn....

    Before
    IMG_1218.jpg

    After

    IMG_1225.jpg

    IMG_1226.jpg
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  17. benno.h

    benno.h cageracer

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    Man I love how clean everything looks after a bit of bead blasting...

    Got the head back on the XR today. New valves look the goods - everything lined up as it should. Here's a vid of the old intake valve:

    https://photos.app.goo.gl/BJPyfVRkPHsFjbJh7

    In the video, I'm rotating the valve (intake) by hand whilst maintaining slight traction (in the direction the spring normally would). An extremely bright LED flood light is shining at the underside of the cylinder head and the camera is pointing down the inlet tract. You can see that as I rotate the valve, it goes from no light to lots of light coming through. I do believe that at some points it's capable of generating enough compression on the kicker to make you feel like everything is normal, and then it rotates to a point with no compression at all.

    I'm still waiting on a parts order from Partzilla in the US to get everything back together. A bit under $200 AUD for cam chain tensioner, shaft, slider thingo, lower cam sprocket and a couple of miscellaneous bolts. Not too bad really - the local dealer wanted $157 for the tensioner alone.

    I've been working on cutting a blank rear guard to suit my new subframe for the last little while and it's coming up pretty good (IMO) but it's been a bastard of a job:
    https://instagram.com/p/BkI-6iinYI1/
    https://instagram.com/p/BkRzUbGHS9T/
  18. lookfar

    lookfar from the land of OZ

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    Took the XRs' camping in Northern NSW.

    Bloody cold... was -4 degrees C
    IMG_1234.jpg

    Riding on a fire trail.
    IMG_1232.jpg

    The XRs' in their element.

    IMG_1240.jpg
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  19. hoorang

    hoorang Rather be riding than working

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    ^^ that last pic looks like it should have been in the sales brochure!
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  20. lookfar

    lookfar from the land of OZ

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    If anyone has done the electric leg 650 conversion to the 600R, where did you put the battery?

    And, is the right sidecover the same between the XRL and the XR?