The bike blues

Discussion in 'Motorized Bicycle Trouble Shooting' started by JangAlang, May 9, 2017.

  1. JangAlang

    JangAlang Member

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    Hello everybody. I got a dilemma with my bike. 79 80 cc motor flying horse. Got about 500 miles or more on it. Stock NT carb. Runs great for about 20 minutes then start acting like it isn't getting gas and just kind of jerks ins acts like it wants to slow down a little bit more like the clutch is slipping. My question is wouldn't the clutch slip from the get-go if the key was slowly coming out. I have an idol it runs fairly good. Until it starts jerking that is. Check the float level everything seems fine but I do notice when it's sitting still the gas disappears from below the fuel filter. Mine C clip is still set at stock. I have a little leak from the case gasket I believe and I tried to gasket it up but only had the black Permatex. Had a loose Jet the other day.im looking at it now so any input is valued..also my mix is 50:1, my plug is choc brown and after i get home i stop and look down and see a "vapor" coming out of my carb filter if that helps. .appreciate it guys beaner
     
  2. crassius

    crassius Well-Known Member

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    after about 8 or more miles, the motor is finally getting up to a stable temperature - you may be going lean at that point or maybe the 50:1 isn't enough then, or maybe fuel flow is lessening a bit

    I'd try opening drain plug and watching flow for a bit - if that looks good, I'd try 32:1 for a tank or so and see if that helps.
     
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  3. Slogger

    Slogger Member

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    -Runs great for about 20 minutes then start acting like it isn't getting gas-
    You may not have a good fuel cap vent. If the tank isn't vented the gas stops after a while. Next time it does that loosen the cap. If you hear a swoosh of air, that's it.
    It could also be getting too hot if it isn't jetted right or ran too hard.
     
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  4. JangAlang

    JangAlang Member

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    Sorry so slow. My gas cap is venting well still..thanks for your input..much appreciated slogger. so a host of problems like a dead spider blocking my crap valve petcock, n a leaky thread in the gas tank. Then my mag side seal came out n stuck to the cutout. So i put a new one in and a week or so later it did the same thing. Tried a new one now n tried not to push it so far in. This motor has the ball looking bearing instead of a sealed bearing (mag side). A 2008 motor from bb. Anyways just thought if ya had any thoughts on why they keep sucking to cut out. Bearings only have slight up n down play but no side to side. Could it be im giving too much gas n blowing it out?i have throttle set for slight turn of handle to pull up slide..always worked before though..anything is gold in my book
     
  5. Greg58

    Greg58 Well-Known Member

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    Not trying to disappoint you but I had this happen to one engine and ended up replacing the bearings. If you have any up and down movement that could be the problem. Think about the crankshaft moving around at 6 to 7k rpms and it easy to see the seal working out, I ended up ordering sealed bearings and removing the inner seal and leaving the outer. I've only test run the motor so I don't know if the problem is solved, I'm going to use that motor on the bike I'm about to build.
     
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