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Pre-spring tear down questions.

Discussion in 'The Garage' started by Garrett411, Mar 19, 2016.

  1. Garrett411

    Garrett411 XS650 Enthusiast

    Hey guys.

    This fall my '79 Xs was popping fairly badly and pulling some heavy vacuum through the right side carb. I suspected a burnt valve or something of the like when i stored it for the winter. Well here i am getting the itch to ride on the nice MN days were getting. So today i pulled the motor from the frame and have proceeded to take the head cover and the head off. The right side head looks pretty dirty and crummy compared to the left. I currently have parts washer fluid in both heads to see if any is leaking past the seats to indicate a bad valve/seat. Early indication seems to be pointing to the right intake to be letting a little by. Anyways just wonder if you guys have dealt with anything like this. Looking for some insight because this is the farthest i have dug into this motor, i've done rebuilds befoer but never on the XS. Do you guys have any suggestions on what else to check while im this deep? I've heard that replacing the front cam chain guide would be a good idea? What about replacing the cam chain? Let me know anything that ya'll would suggest! Thanks guys!
  2. Garrett411

    Garrett411 XS650 Enthusiast

    Also to be clear i tried replacing the old carb boots because they were a little cracked thinking this was the problem right away. Well the new ones that i had purchased were chincy as hell and bowed when tightened to the head. Any suggestions on what i should do with the originals or new ones to buy?

    Another quick question is that im not sure if this is a crank position indicator wire or what but i has come off the top of the crankcase and is a real bitch to get it to stay on. is it necessary? What is it, if it's needed ill just splice in a better attachment and call it good? I've attached a picture of it.
    Thanks guys
  3. weekendrider

    weekendrider Iron Horse cowboy Top Contributor

    S.W. MO
    Your neutral safety switch wire? Blue with a black boot on it?
    Some early ones were spring loaded, later ones had a screw to keep the wire in place.
    Maybe squeeze the tangs tighter?

    You didn't mention mileage but I would consider changing the guide and cam chain at one time.
    Clean up the rough stuff in the exhaust ports. How much you clean is up to you.
    5twins is good to leave his photobucket account open to visitors(send him a pm of thanks) so clicking on any of his pictures will get you there. He has some great shots of his head work. And a ton of other valuable stuff.
    Inspect the valves and valve seats. Lap them before re-assembly.
    You are there so have the cylinders and pistons checked for wear.
    A new set of standard size rings may get you back to snuff.

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