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Cam Chain Adjustment

Discussion in 'The Garage' started by gene xs, May 23, 2020.

  1. gene xs

    gene xs XS650 Enthusiast

    My apologies - I know that this has been done to death....

    1980 XS650 Special II. Just reassembled after changing the front cam guide and tried to adjust the tensioner. Haynes says tighten it until the rod is flush with the top of the threaded piece. I do that but it feels way tight, so I remove the tensioner to take a look. When the rod is flush with the top, there is zero travel. The nose is bottomed out. So I reinstall and adjust so that the rod is 1 mm below the top and does not reach the top as I spin the engine.

    I figure that I am OK here, but what the heck? I've seen on the forum that the rod should be 1 mm proud of the top, but that would not work here either.
  2. thuban

    thuban Horse Scratcher XS650.com Supporter Top Contributor

    Unless the planets are right, your never gona get the rod end to stay even with the end of the adjuster as you turn the engine. That rod is going to move in and out a bit because of wear on the chain, gears and movement of the valves. Your shooting for a happy medium of not too far in and about the same amount out as you turn the engine, with the ideal of flush and just barely pulsing. If things are really too tight, well, it should not be if the guide was the same in all respects as the one removed and installed correctly. Only you know that. Your on the right track. Put it where you think, then start it and see whats , whats.
    If it's a new chain, mine was tight!
    gggGary likes this.
  3. 5twins

    5twins XS650 Guru Top Contributor

    Best, easiest, and most foolproof way to set the cam chain tension is to do so while the bike sits there idling. Adjust it so that you get just a small amount of in-out movement of the plunger, maybe a MM or so. No movement means you've set it too tight so you can momentarily do that then back it off until you get the small amount of movement required.
    thuban likes this.
  4. gggGary

    gggGary Stop that! XS650.com Supporter Top Contributor

    What 5twins said but it can most easily be done with the spark plugs out, using the electric start. So nice not having a hot motor to deal with. :wink2:
    Don't forget to put the plugs on the wires and ground them before cranking.
    Expect to reset in a hundred or 2 miles as the new chain beds in.
    thuban likes this.
  5. GLJ

    GLJ Never go faster than your guardian angle can fly. Top Contributor

    Something there doesn't sound right. Can you remove it and post some pics?

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