beating head against wall. broken shaft?

Discussion in '2-Stroke Engines' started by spunout, Feb 11, 2008.

  1. spunout

    spunout Member

    i searched the posts. but the truth, friends, is that time is always against me.

    thats a powerking P.O.S. and after 13 miles, the drivetrain wont fully engage. look at the small gear on the right, with the X...that shaft will only sometimes turn with the gear. i tried tightening and loosening the slot, to no avail.

    i know its supposed to turn all of the time.
    thanks in advance, Happy

    Attached Files:

  2. cooltoy

    cooltoy Member

    It's your lucky day. You broke your "key" and for a couple of bucks and an hour of your time you will be back on the road. Have a great day.
    Try searching "key"
  3. fetor56

    fetor56 Guest

    You said it only "sometimes" that means it does turn?
    Under what conditions does it turn and when it does turn does the engine run properly?

    PS...looks like cooltoy answered your question...he's pretty accurate so i expect your problems solved.
    Last edited by a moderator: Feb 11, 2008
  4. spunout

    spunout Member

    aw, CARP! a key! just like the drive sprocket, huh. thanks cooltoy.

    fetor: when i say 'sometimes' i mean while i was diagnosing the patient, and turning clutch disc gear by hand. it never 'caught' again with engine running, so its painfully (and ashamedly) obvious cooltoy is right.

    thanx guys
  5. iron_monkey

    iron_monkey Guest

    Make sure you reuse the stock washer or use another 'flower washer'.

    I found that using a normal flat washer in place of the stock flower washer means the small gear will move back and forth along the shaft making a clanging noise as the flat washer wont secure the gear properly.
  6. dgray56

    dgray56 Guest

    Consider yourself lucky....

    It would appear you have *possibly* just sheared the gear key on the final drive shaft. This can happen from something as unpredictable as a pre-ignition firing occuring opposite the normal stroke-firing pattern that vectors thrust at just the wrong time. Hopefully the shear pin gave up and it didn't toast the drive shaft.... Anyway, I had a much worse situation where the flywheels, needle bearings and rod siezed on my 70cc at high rpm (well over 40 mph). At decceration, the bottom end of the engine experienced severe oil starvation that immediately toasted the bottom end of the engine. You can't buy just a new rod and bearing set. You have to buy the entire lower end that will cost you about $54 bucks. That's still pretty cheap but it'll take a couple of hours of time to do the rebuild. After considerable testing and modifications I have come to the overall conclussion that these 2 stroke engines are in general pretty crappy. It has taken considerable re-machining and modifications to make this one reliable and get real performance out of it. I'm getting flat out speeds around 50 mph, and pretty decent acceleration, but what I was really looking for was durability. I've switched to a 4 stroke application with a pull start, centrifigal clutch and 2 speed trans. Heavier and less hp but much more torque, smoother, less noisy, no fuel mixing, no clutch issues, simpler to operate and above all else.... durable. The two strokes can be made to work much better, but not by a novice. If only there was a way to get the manufacture to put more effort into overall quality control this could be a winner, but the bottom line is the effort to clean this power plant up, just kills it's practical application. Of course this is just my informed 2cents worth of opinion ;-)
  7. gone_fishin

    gone_fishin Guest

    hi dgray...nice post, you do seem informed. i just noticed you joined some time ago, there's been a change since's forum policy to "introduce yourself" sure goes a long way towards validating your opinions and advice if we know who's giving it :)
  8. azbill

    azbill Active Member

    you will be surprised at how many people say HI ! as well

    happy, I hope your up n runnin soon :D
  9. iron_monkey

    iron_monkey Guest

    This must be a joke; its got nothing to do with reliability/durability or quality control. You were clearly abusing your engine.

    Actually, I dont even think its even physically possible to go 50mph with these engines even with a 36t sprocket. You must be crazy and lucky to be alive that the engine didnt seize/jam/implode/etc at 50mph.
    Last edited by a moderator: Feb 17, 2008