Low Power Trouble

Discussion in '2-Stroke Engines' started by dillondonnelly1, Mar 31, 2014.

  1. dillondonnelly1

    dillondonnelly1 New Member

    Hello, everyone. I need some help with my bike.

    Recently my bike lost a lot of its power. It used to go right up hills, but now I really have to pedal for it to go anywhere. I max out at around 23 mph. It used to hit 40 mph on a flat stretch with no problem. I tried a few things to fix it, but they seem to have failed to work.

    Here is a list of the things I did/checked:

    - Replaced carb (twice)
    - Adjusted the clutch wire
    - Checked Gas Mixture
    - Replaced Spark Plug
    -CDI and Magneto (Used a multimeter and set it on 2k. The readings were fine.)

    The magneto read 337ohms and the CDI read 740ohms.

    I hope someone can help me figure this out!


    Regards, Dillon
     
    Last edited: Apr 2, 2014

  2. jaguar

    jaguar Well-Known Member

    take the engine apart and make sure the rings aren't stuck or broken. Plane down the head and cylinder top to be perfectly flat to prevent power loss thru compression loss.
    tighten the screws holding the stator coil on.
    make sure the air filter isn't clogged.
    check the crank seals for air leaks.
    make sure there isn't a dead mouse in your exhaust. ha!
     
    dillondonnelly1 likes this.
  3. butre

    butre Well-Known Member

    Does it sound like it's hitting the same RPM that it always has? If so, maybe the clutch is slipping.
     
  4. dillondonnelly1

    dillondonnelly1 New Member

    It does. Could the clutch be slipping already? I just bought this motor 2 months ago. But then again it could be a defect.


    Also, do you think it could be the throttle?
     
    Last edited: Apr 1, 2014
  5. dillondonnelly1

    dillondonnelly1 New Member

  6. velzie

    velzie Member

    Have you already done what has been suggested? What are your results? My poor running conditions, I believe, are because of big temperature changes (it also may be a leak, but i havent had time to check). Check for leaks then see what jet you have vs what you may need for your temp/elevation. Do a plug chop to see how lean/rich you are running.
     
    dillondonnelly1 likes this.
  7. dillondonnelly1

    dillondonnelly1 New Member


    Yes, I have done everything as suggested. Nothing worked so far. I don't think there are any air leaks leaks because I switched it out with a few different carbs and none of them worked. Also, I know it isn't the temperature change or the oil mixture because my other bike is using the same gas as this one and it runs just fine. They are both the same motor too. It's not the CDI or the magneto. I tested both the magneto and the CDI with a multimeter (yes, it was on 2k) and the readings were just fine.
     
  8. jaguar

    jaguar Well-Known Member

    the multimeter don't tell you ****
    I know. I'm an electronics technician.
    There is no good way to test for spark strength other than possibly greatly increasing the gap and see if the spark can jump it.
    When I test the CDI I make, the plug I use has a big gap.
    But I don't have a specific recommendation for you. What complicates things is that inside the engine the compression makes it harder to spark.
    Until you swap out the CDI and stator coil you can't rule it out as being the culprit.
    All sparks are not created equal. The stronger the spark, the better the engine runs.
     
    dillondonnelly1 likes this.
  9. ua2pants

    ua2pants Member

    i'm amazed nobody said anything about your head gasket or base gasket.. even your exhaust gasket. make sure none of those are blown. if any of them are, that would cause an almost complete loss of compression resulting in power loss with the same rpm.
     
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  10. ua2pants

    ua2pants Member

    and dont get me wrong jag, but the head and jug wont matter if the gasket is bad. to test if its a leak like that without any other types of tools, release your clutch to lock your rear wheel and put some body weight on your seat from your chest. slowly try pushing the bike forward, if it moves easily, you have a leak somewhere, if it doesnt, then it's probably dealing with your carb or cdi as jaguar suggested.
     
  11. mrfubs

    mrfubs New Member

    if you lost that much power check the condition of the cylinder wall, piston and piston rings. make sure to use the same blend of fuel and octane of fuel as before. if the engine sounds like it it revving high soon after you start off then your clutch is slipping and you will need new clutch pads, replacing the carburetor will not help although i recommend a cns carb and do lots of research how to tune it you will need to buy jets and a jetting hand drill to drill out the pilot jet if needed. you will see a big power incresase if your cylinder and piston/rings are in good condition. also be sure the carb is tightly fastend to the intake, is it possible you have a bad crank seal and sucking in air through crank seals.
     
  12. jaguar

    jaguar Well-Known Member

    velzie already said "check for leaks" which includes crank seals, base gasket, crankcase, head gasket, spark plug cracked or not screwed on completely, intake manifold leak.
     
  13. velzie

    velzie Member

    A few thoughts:

    Have you done anything to the motor recently? Are you running stock compression? Could the carb jet be blocked? Maybe exchanging parts from the poor running motor to the better running motor will help diagnose the issue( spark plug, carb, cdi, rotator magnet). What kind of leak testing are you doing? i.e. are you spraying aerosol around the motor and listening to rev changes??? Check around the bearing seals too...

    hope that leads to something.
     
    dillondonnelly1 likes this.
  14. dillondonnelly1

    dillondonnelly1 New Member

    It doesn't move at all. The wheel stays locked.
     
  15. dillondonnelly1

    dillondonnelly1 New Member

    I didn't notice something kind of strange with the spark (on all of the spark plugs used too). It seems like the spark isn't very bright. I'm not exactly an expert with motors so I don't know if this is normal or not. The reason I suspect something is because in one of the diagnostic videos I watched, the spark looked way more powerful. But then again, it could just be me.
     
  16. Fabian

    Fabian Well-Known Member

    What are you complaining about.
    That's faster than my bike goes and it has just about every aftermarket and billet performance part thrown at it.
     
  17. dillondonnelly1

    dillondonnelly1 New Member

    Yes, that is indeed fast. But the problem is that the bike has low power. In Pennsylvania, (the area where I live anyways) there is a lot of hills. I just want to go for a cruise without putting too much work into it. Yes, I like to pedal from time to time, but sometimes I just want to relax.

    By the way, I think you might be experiencing a problem as well. Your bike should go well over that.
     
  18. Fabian

    Fabian Well-Known Member

    Have you thought of not being so concerned about the 40 mph number and fixing the problem by properly calibrating your bike speedo to give a more realistic and accurate top speed figure?




    I might be more to do with the fact that my bicycle speedo is properly calibrated and i haul a little extra weight.
     
  19. dillondonnelly1

    dillondonnelly1 New Member

    What are you talking about? I can tell it's a lot slower. I compared it with the other bike I have (same kit).
     
  20. Fabian

    Fabian Well-Known Member

    Maybe you were not actually going 40 mph, unless it was gravity and wind assisted top speed.
     
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