1. Dismiss Notice
  2. Hey Facebook people... We've created a group for XS650.com members to connect. Check it out!
    Dismiss Notice

too hot, cuts out

Discussion in 'The Garage' started by blacklav, Nov 20, 2020.

  1. blacklav

    blacklav XS650 Member

    15
    7
    3
    lincs
    Hi all. My xs D model has started to cut out, it happens when ive been for a ride and then have to idle in traffic for a while ( getting very hot ). It will not start again for about 20 seconds and then its fine. Its done this the last three times out and always on a hot day. Now ive checked the ignition wiring for any loose connections that could seperate due to the heat and all ok.
    Someone suggested its the fuel evaporating in the carbs. It certainly seems like a temporary fuel blockage, but why would it happen on both carbs at the same time?
    If its evaporation, surely the fuel would instantly refill the carbs from the tank as the floats go down, or am i missing something about the workings of the carburetors.
    Any suggestions appreciated.
     
    Paul Sutton likes this.
  2. RustiePyles

    RustiePyles Semper Fortis

    Is your cap venting? Try opening the gas cap next time it does it. Also could be a vacuum issue, try turning the petcock PRI next time and see if that helps.
     
    Paul Sutton likes this.
  3. blacklav

    blacklav XS650 Member

    15
    7
    3
    lincs
    Thanks for the reply.
    Tried that, it only does it on idle not when riding. There isn't a prime on my taps, just on and reserve.
     
    Paul Sutton likes this.
  4. RustiePyles

    RustiePyles Semper Fortis

    What's your Idle set at? these bike dont really like anything <1300rpm
     
  5. blacklav

    blacklav XS650 Member

    15
    7
    3
    lincs
    About 1100. Only does it when the weather is really hot. I've left it idling in the garden for 10 mins on a cooler day with no probs.
     
    Paul Sutton likes this.
  6. gggGary

    gggGary I'm listening, change my mind XS650.com Supporter Top Contributor

    If they are "vapor locking" Try full throttle for bit while cranking. a vapor lock is pretty much like a flooded cylinder the fuel vaporizes and displaces all the air so no combustion can occur. WOT will pump the vapor through, let in some air. Typically normal starting throttle, ie just a bit above idle, then slowly go to WOT, crank for a few seconds then back to normal starting throttle, try again. Lot of times the motor will catch as you open throttle,
    This could be a sign of leaking float valves or high fuel levels in the float bowls.
     
    Paul Sutton likes this.
  7. Paul Sutton

    Paul Sutton Still Looking Good Top Contributor

    When I first added an inline fuel filter the extra tubing was closer to the engine and the line would vapor lock. Petrol starts forming vapor bubble at about 30 - 40 Celsius. I had to relocate the filter and fuel lines further back to solve the issue.
     
    gggGary likes this.
  8. Paul Sutton

    Paul Sutton Still Looking Good Top Contributor

    Forgot to mention the vapor lock was particularly bad where the tubing made a U bend down then up to the carb T connector between the BS34s (81SH). So try to keep the tubes as direct as you can to the carbs.
     
    gggGary likes this.
  9. blacklav

    blacklav XS650 Member

    15
    7
    3
    lincs
    Thanks Paul. All the tubes run down wards so no air block and are away from the heat.
     
    Paul Sutton likes this.
  10. blacklav

    blacklav XS650 Member

    15
    7
    3
    lincs
    Thanks Gary I will check the float levels.
     
    timbeck, Paul Sutton and gggGary like this.

Share This Page