1. Dismiss Notice
  2. Hey Facebook people... We've created a group for XS400.com members to connect. Check it out!
    Dismiss Notice
  3. Want an XS400.com t-shirt? Go to the store to order. Limited sizes and quantities available.
    Dismiss Notice

Top end ticking/knocking

Discussion in 'The Garage' started by MrPURPL3, Sep 12, 2021.

  1. MrPURPL3

    MrPURPL3 XS400 New Member

    Hello guys, I recently ran into some trouble with the bike and I am hoping someone can guide me to figure out what I can do. The bike turns on goes into gear well but once I try to throttle it, it seems unresponsive to actually move the bike beyond 30kph. I've checked and adjusted the valves and everything seems in spec, and I even used a jack to keep the engine at TDC for both cylinders. I am just wondering if I am going to have actually open the top end and be surprised with something beyond my mechanical capabilities.
     
  2. Buddha

    Buddha XS400 Enthusiast

    Sounds like excessive rocker/valve clearance IMHO. Explain exactly how you adjusted the valves.
     
  3. MrPURPL3

    MrPURPL3 XS400 New Member

    First I put the bike on the middle stand, removed the seat,tank etc., removed that stator cover, the valve view plugs and the spark plug to see the piston. I turned the crank until i reach LT and kept the breaker bar in place with the jack so it wouldn't turn back. I would check that the rockers were in free play and adjust the valve clearance to 0.08 - 0.12 mm for intake and 0.16 - 0.2 mm for exhaust (exhaust ones being the view ports that are at the top front portion of the engine). Once the LT was done I would move the crank forward until RT and repeat. Once done I just put everything together but never turn the crank again after adjusting for RT.
     
  4. Buddha

    Buddha XS400 Enthusiast

    Sounds like you did it the way I would have. Just double check that when your on LT or RT that the cam lobes are in the TDC to fire position for each cylinder.
    Have you checked the compression as is?
     
  5. MrPURPL3

    MrPURPL3 XS400 New Member

    I haven't checked compression yet and will need to by the tool to do so. For now based off what you hear I might try going tighter on the clearances by getting a diff set of feeler gauges. Would dropping down to 0.06/0.07 mm for intake for eg. be too tight of a clearance? I only ask bc we are dealing with an almost 40 year old engine, perhaps the wear on the engine requires a closer clearance than the initial specs of the 80s? Also I am going to try to be ultra super meticulous and ensuring that I am not moving back on TDC and that Im def on the firing position.
     
  6. Buddha

    Buddha XS400 Enthusiast

    I would set the valves to spec, you shouldn't have to go tighter.
     

Share This Page