Bike is bogging bad!Need help!

Discussion in 'Motorized Bicycle General Discussion' started by fall_down_stand_up, Jun 10, 2009.

  1. fall_down_stand_up

    fall_down_stand_up New Member

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    I Have a 70cc 2 stroke motor that I bought from thatsdax,actually its my 3rd motor I have bought over the years....A couple days ago I was on my way home and it started bogging out really bad and I had to put the choke halfway on the drive....When I got home I took the carb off and the needleseat had unscrewed and was in the bottom of the bowl so I screwed it back in and put it back togeather and had the same problem....I checked the plug and it was not running lean....So I took one of my extra carbs laying around and put it on and had the same problem with it bogging out....I then checked the plug again and it was white and running way to lean....So I built a new intake gasket from a gasket kit I had laying around and put a O ring in the carb to go into the intake....Fired it up and still the same problem....When I take off I have to keep the choke over halfway on....The motor has exellent compresson....I also took the tank off and checked the filter and then checked the gas filter going to the carb to see if they were clogged but they are fine as well....Could it be a weak magneto?What is going on?Please help!

    Thanks
    John-John:-||
     
  2. NunyaBidness

    NunyaBidness Active Member

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    It does sound like you have an air leak somewhere. I had the same problem once on the way to church. When I put the choke on so it would act right, the intake kinda moved. I found that the bolts that secured it to the motor had come loose. Once they were tight again it ran like a champ. I'm not saying that you're having the same problem but from your description it does sound ilke you have an air leak somewhere.
     
  3. fall_down_stand_up

    fall_down_stand_up New Member

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    Thats what I thought but I dont think so....Im in texas and its been in the 90's so I have been running it rich on the oil mixture....Im going to take the exaust pipe off and see if it is plugged....If anyone else has some idea's please let me know what else it could be....
     
  4. fall_down_stand_up

    fall_down_stand_up New Member

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    Ok,I took the exaust pipe off and its not clogged so im getting good flow....I put a 3rd carb on it with a bigger needle and seat and its still doing the same thing....Its bogging when I give it gas and I have to keep the choke on....Im thinking its the magneto or the sparkplug....I would just put another magneto on it but I dont have an extra one and it will take 5 to 7 days to get here and that is the only transportation I have....Man im screwed....Does anyone else have any idea's of what can be causing this????Please help....
    Thanks
    John-John
     
  5. Shadeslay

    Shadeslay New Member

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    If it runs better with the choke on, it really sounds like an air leak. That air has to come from somewhere or the motor will cut out.
     
  6. fall_down_stand_up

    fall_down_stand_up New Member

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    I couldnt agree with you more,but there is only 2 places the air could get in,eather the intake going into the head or were the carb slides onto the the intake and its not leaking from what I can tell and the sparkplug is not white now so its not running to lean persay....Its the crazyest thing....I will take the intake back off tomorrow and see if the new gasket going into the head is ok....

    John-John
     
  7. Junster

    Junster New Member

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    Check the cylinder base, and look for oil coming from either of the seals on the crank.
     
  8. fall_down_stand_up

    fall_down_stand_up New Member

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    Thanks....I found out it was the magneto after all....I ordered one and it will be in monday or tuesday...
     
  9. Junster

    Junster New Member

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    Wow glad you found the problem. First I ever heard of a mag that only kinda ran. Usually they're an all or nothing kinda deal.
     
  10. fall_down_stand_up

    fall_down_stand_up New Member

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    This is the second time I have had a problem were the magneto worked barly....the other 2 just went out completely....The lasttime this happened it spit and sputtered and would cut in and out going down the road,but went out completely the next day and I had to buy another one....My dad said that if any kind of metel debree gets in on the windings that it can short and reduce the output of the magneto without completely going out....Have you had magneto problems?This is the 4th magneto I have gone through over the last 3 years on different 2 stroke motors(I have 3 of them)so I know its not just something wrong with this motor causing a short and making them go out....I found a site one time that sold a high end magneto that said that they are wraped better and eliminates this on going problem,but I cant find the site again(I should have put it on my favorites)....
     
  11. Rockenstein

    Rockenstein New Member

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    I'm sitting here thinking about the problem I'm having with my engine at the moment and wondering if on these mags the windings are not wound tight enough, not enough epoxy etc etc and the engine vibration is causing the coating on the winding wire to fail which results in complete or intermittent short.

    Last time I tried to get my bike going the magneto winding was warm to the touch...don't know if that's normal or not because I never touched the mag after running it.
     
  12. GraingerDoodTim

    GraingerDoodTim New Member

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    im sitting here thinking the same as this dood. But also realizing that, why just today, I saw some mystery oil on my bike. But when I run my bike wide open, it seems to do good until i get high on the rpms then it boggs out until I let go of the throttle. the good news is that i hate running the thing wide open anyways, but it still stinks that i could not even if I wanted to. I have to check it out, replace gaskets, and maybe the magneto. Also where do you guys get your spark plugs? Or what size are they.
     
  13. zendiecut

    zendiecut New Member

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    I swapped out carbs, changed jets, adjusted the needle. No leaks any where on the engine. I was thinking the same about the mag. I'm exhibiting the same things as granbury_man. Now I'm thinking of swapping out the mag from my other bike.

    Does any one know what the resistance of the mag should be?
     
  14. zendiecut

    zendiecut New Member

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    I don't know that yet. Haven't swapped them out yet. Or maybe you're talking to someone else.
     

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