Cold motor start

Discussion in 'Motorized Bicycle General Discussion' started by wes, Sep 23, 2009.

  1. wes

    wes New Member

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    This motor runs really well once it warms up but it takes up to 100 yards before it will fire up when its cold, sometimes it only takes 30-50 feet, all of my other motors fire as soon as i let out the clutch. I have the needle at the top and i still have the stock plug in it, anyone had this problem??dnut
     
  2. BarelyAWake

    BarelyAWake New Member

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    Um no - but I just wanted to mention the stock plug is a total POS, replace it with a NGK BP6HS.

    ...and needle at the top? Do you mean the clip setting? This would put it at it's leanest - so check your plug color & try a lil choke to start.

    Last but not least try just a tap or two on your primer to give it a bit of fuel before attempting to start ;)

    It's all I can think of...
     
  3. EnFlaMEd

    EnFlaMEd New Member

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    Mine was good till I changed to a higher comp head. Now its a bit of ***** to start on cold mornings but when the weather is warmer it starts piece of piss.
     
  4. Sydneysider

    Sydneysider New Member

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    air leaks at the intake no matter the size will make the motor harder to cold start.. its probably running better after warming up because gaskets expand and seal up the holes
     
  5. xlite

    xlite New Member

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    I noticed this too. Hard to start and takes longer to warm up. With my new tuned expansion chamber it's much worse. Unfortunately I'm addicted to both hop-ups and there's no going back. :)
     
  6. wes

    wes New Member

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    Ummm I thought i solved the air leak problem, but come to think of it i have not put any rtv on the intake to cylinder mate, this motor runs strong when its cold and cant hardly choke the thing either, the clip is at the top setting and i willl check the plug in a while, what do you think of the bp7hs i herd this is a cooler plug for NGK, but i have one that is still new!!!
     
    #6 wes, Sep 23, 2009
    Last edited: Sep 23, 2009
  7. Venice Motor Bikes

    Venice Motor Bikes Custom Builder / Dealer/Los Angeles

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    Hard starts aren't a plug problem! They're mostly a carb problem.
    Stick with the #6 plug.
    The trick to starting a hard to start engine is just finding that "sweet spot" on the choke!!! It's usually around 2/3 - 3/4 of the way closed.
    Also, beefing up your ignition system will help! (better wire & boot, & solder the CDI wires)

    One more thing... too much oil can cause plug fouling (& hard starts). Use regular 2 cycle oil mixed 24:1 for the first two gallons, then switch to 32:1 after that.
     
    #7 Venice Motor Bikes, Sep 23, 2009
    Last edited: Sep 23, 2009
  8. wes

    wes New Member

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    Thanks man i tried the choke at half way and put that ngk plug in that i have, this was the first time ive checked the plug in the first 500 miles and it looked good but was a little dirty probably due to the break in period, this fixed the problem, and as far as mix i ran 24:1 for break in of decent standard oil and now rum amsiol at 50-60:1
     
  9. chrisme

    chrisme New Member

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    To start I generally twist in the idle screw, put the choke all the way on, pick up the back of the bike and step on the pedals. Just a quarter turn the engine fires right up in 40° weather. I then close the choke, let it idle high for a bit to warm up, turn down the idle and ride.
    I ALWAYS let the engine run for a bit before I ride to make sure all the bearings are being well oiled. 2-strokes are prone to cold seizure if run hard without being warmed up. This has worked for over 3000 miles, so I'm keeping it up.
     

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