Clutch not engaging suddenly?

quaternium · Mar 9, 2015

I have a two-stroke China girl 49cc. Suddenly, while riding, I had loss of power to the drive and a high engine rev, and pedaling was EASY / not the usual tension I'm used to with clutch engaged. I took off the clutch cover and noticed the large screw holding the small bevel wheel is loose. Could that be it? I'm not even sure if this is a clutch problem. The clutch handle moves the clutch plate as I assume it should.
Bear with me, please, as I'm entirely new to working on these motors (or any motors)
Would this be considered a total compression loss? Clutch slipping? I'm not sure if I should/have to tighten the screw holding the small bevel wheel? Or start messing with the clutch plate and flower nut? Sheared woodruff key? I'm lost.

Kioshk · Mar 9, 2015

It sounds like that small gear has slipped off its woodruff-key; that's the little orange-slice looking chunk of metal that slips into the crank's notch and mates with the slot in the bevel-gear.

The key may still be in the crank-slot...it looks like this:

...and it keeps the gear from slipping. If it needs replacing...do that, then replace the bevel-gear, and then torque down that big screw. You can use LokTite Blue on the screw to keep it from loosening.

quaternium · Mar 9, 2015

Thanks Kioshk. I did figure out that the woodruff key was missing. I tried finding these online. About 3 sources for $3 a piece, but all wanted $10 or more for shipping! I'm mad, so haven't yet.
Rumor is that a 3/16" woodruff key from US hardware store MIGHT work. What do you think?

fatdaddy · Mar 9, 2015

I just buy key stock and make my own keys rather than pay that much AND wait a week or two for shipping, And you can usually get a better grade metal doing it this way. BUT it is a P.I.T.A to get it shaped to exactly the right size.
fatdaddy. usflg

2door · Mar 10, 2015

My local Ace Hardware has both SAE and metric woodruff keys. They have three drawers of keys in every size you'd ever need for small stuff like our engines.

SAE keys can be sanded/ground a little thinner to fit a metric keyway.

Tom

fatdaddy · Mar 10, 2015

2door said:
My local Ace Hardware has both SAE and metric woodruff keys. They have three drawers of keys in every size you'd ever need for small stuff like our engines.

SAE keys can be sanded/ground a little thinner to fit a metric keyway.

Tom

Never even thought to check ACE for woodruff keys, And there's one just down the road from me. Thanks Tom.
fatdaddy.

Tyler6357 · Mar 11, 2015

Once mine fell out, I used a magnet reacher to slide around inside the case and when I pulled it out there was a woodruff key stuck to the magnet covered in grease. Yours might be in the case or stuck to grease too, look carefully. You don't want it to get sucked into the cylinder after you put a new one on.

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Clutch not engaging suddenly?

quaternium

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