Hard starting when hot after sitting 30 minutes
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  1. #1
    Junior Member garyg200's Avatar
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    Hard starting when hot after sitting 30 minutes

    Greeting from a TW200 newbie.
    I have a 2006 TW with only 1700 miles that runs great. But after riding for a while and shutting off it is very hard starting after sitting for 20-30 minutes. Starter just cranks; choke, no choke, it doesn't matter. If I hold throttle wide open and continue cranking it sputters and will eventually, reluctantly, come back to life and then run fine. I suspect some type of a vapor lock issue but have not seen any similar problems from fellow TW owners. Next time it happens I am going to open the gas cap and see if there is a venting issue but in the meantime I thought I would see if anybody has additional suggestions. Thanks Much

  2. #2
    Senior Member SportsterDoc's Avatar
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    When shut off, is the petcock also shut off?
    If not and if float valve is leaking, it may be flooding.

    When it will not start right away, pull plug to see if it is wet.

    If this is the cause, then cleaning carb should be done and oil changed, as it is likely dilluted with fuel

    ...and welcome to the forum.
    Last edited by SportsterDoc; 07-22-2019 at 09:18 AM.
    2014 Honda CB1100
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    2017 Yamaha TW200
    2012 Triumph Bonneville
    2002 H-D Sportster 1200 Sport
    2003 H-D Sportster 883
    1976 Honda CB750F
    1975 Honda CB360
    1970 Yamaha CT1
    1972 Yamaha CT2
    1972 Yamaha AT2/CT2
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  3. #3
    Senior Member SportsterDoc's Avatar
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    BTW, vapor lock occurs when fuel vaporizes on the inlet side of a fuel pump, typical with an engine mounted mechanical pump.
    In the seventies, this was mitigated by recirculating unused fuel.
    With tank mounted electric pumps, pushing fuel, this is not a common issue, even in very hot weather.

    For a gravity flow system, this should not be a concern.
    2014 Honda CB1100
    2018 Yamaha XT250
    2016 Moto Guzzi V7 II
    2017 Yamaha TW200
    2012 Triumph Bonneville
    2002 H-D Sportster 1200 Sport
    2003 H-D Sportster 883
    1976 Honda CB750F
    1975 Honda CB360
    1970 Yamaha CT1
    1972 Yamaha CT2
    1972 Yamaha AT2/CT2
    1970 Honda SL350
    1970 Honda CL350
    1967 Honda CL160
    1967 Honda CB160
    1962 Honda CA110

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  5. #4
    Senior Member RaZed1's Avatar
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    If you need to hold WOT for a while before it sputters to life it sounds like it's flooding out. Most likely from a leaking float valve.

    The way to diagnose this would be to turn the petcock off maybe 30 seconds before shutting the engine off. This should use up the fuel in the line and isolate the tank so there is no head pressure "pushing" fuel against the valve, and thus potentially into the engine's intake side.

    Let it sit for 20 minutes or whatever and then go to restart it. If it starts easily, you found the problem. Replace float needle. I'm fairly sure this will be the case.

  6. #5
    Junior Member garyg200's Avatar
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    Interesting. Never thought of doing that. I will give it a try. Thanks for the tip

  7. #6
    Junior Member garyg200's Avatar
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    Thanks SportsterDoc. Hoping the float valve isn't leaking. I always shut the petcock off as soon as I shut the bike off. It has a fresh oil change. Oil level is right where it needs to be and there is no gas smell in the oil. I will try pulling the plug next time to give it a look...THANKS

  8. #7
    Senior Member SportsterDoc's Avatar
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    With the petcock shut off, leakage past the float valve would be limited to what is in the fuel line, assuming the petcock shuts off completely.

    Although this is not the only possibility, it is probably the most likely.

    Excellent suggestion from RaZed1 re shutting off petcock early, although needle may be OK, if the issue is debris.
    2014 Honda CB1100
    2018 Yamaha XT250
    2016 Moto Guzzi V7 II
    2017 Yamaha TW200
    2012 Triumph Bonneville
    2002 H-D Sportster 1200 Sport
    2003 H-D Sportster 883
    1976 Honda CB750F
    1975 Honda CB360
    1970 Yamaha CT1
    1972 Yamaha CT2
    1972 Yamaha AT2/CT2
    1970 Honda SL350
    1970 Honda CL350
    1967 Honda CL160
    1967 Honda CB160
    1962 Honda CA110

  9. #8
    Senior Member MtnMan75's Avatar
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    Quote Originally Posted by garyg200 View Post
    If I hold throttle wide open and continue cranking it sputters and will eventually, reluctantly, come back to life and then run fine.
    There is also the possibility your mixture is just set too rich, which could make starting cold not an issue but hot starts, a problem. If you aren't shutting off the petcock every time you're done riding, I wouldn't suspect the float valve as the problem as it would still be an issue even on cold starts. If you do always shut it off, then the float valve is suspect. I know a lot of folks tend to think a cold engine doesn't need choke, but unless it hot as heck outside and the bike has been sitting in the sun, you really should have to use it if only for a few moments on the initial startup. If it turns out the float valve doesn't seem to be the issue, check your mixture setting while the engine is hot and adjust your idle RPMs to stay between 1300-1500 (I tend to run toward the 1400-1500 side of it). Adjusting the mixture will make this drift along with it, and especially on a smaller engine, correcting the mixture if it is too rich or lean tends to move idle RPMs out of specs. Hope you figure it out!
    Last edited by MtnMan75; 07-22-2019 at 08:21 PM.

  10. #9
    Senior Member SportsterDoc's Avatar
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    Good suggestions re mixture, but float valve would not be eliminated from cold starts, as fuel in the line from petcock to carb may drain then dissipate during cool-down
    2014 Honda CB1100
    2018 Yamaha XT250
    2016 Moto Guzzi V7 II
    2017 Yamaha TW200
    2012 Triumph Bonneville
    2002 H-D Sportster 1200 Sport
    2003 H-D Sportster 883
    1976 Honda CB750F
    1975 Honda CB360
    1970 Yamaha CT1
    1972 Yamaha CT2
    1972 Yamaha AT2/CT2
    1970 Honda SL350
    1970 Honda CL350
    1967 Honda CL160
    1967 Honda CB160
    1962 Honda CA110

  11. #10
    Senior Member SHAG's Avatar
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    Quote Originally Posted by garyg200 View Post
    Greeting from a TW200 newbie.
    I have a 2006 TW with only 1700 miles that runs great. But after riding for a while and shutting off it is very hard starting after sitting for 20-30 minutes. Starter just cranks; choke, no choke, it doesn't matter. If I hold throttle wide open and continue cranking it sputters and will eventually, reluctantly, come back to life and then run fine. I suspect some type of a vapor lock issue but have not seen any similar problems from fellow TW owners. Next time it happens I am going to open the gas cap and see if there is a venting issue but in the meantime I thought I would see if anybody has additional suggestions. Thanks Much
    Bike sitting for 30 minutes is not hot anymore. Try half choke (or none) and no throttle depending on any carb changes (if any) from stock.
    Go like hell, You'll get there quicker!

    2005 BMWR12GS Rock Red 106k miles
    2013 TW200 - 8k- miles
    2018 X-MAX - 6k- miles

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