Engine Trouble Woodruff key keeps coming out

anonvx

New Member
Joined
Jan 2, 2019
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19
Hi, so I posted about a similar issue before. I bought a bike kit and built it. I drove it for about 3 hours with breaks in between each use so I wasn't driving it for longer then 20 minutes. I was about to make a turn so i engaged the clutch and when i disengaged the clutch I had no power. The engine ran but no power. I suspected the clutch but upon further investigation I found that the gear that was connected to the crankshaft was spinning freely. I bought a new one and installed it. It only temporarily fixed the issue. I took it out for a quick test drive and it started fine and drove about 6 feet when i engaged the clutch to turn and when i released it had no power again. Any ideas?
 


FurryOnTheInside

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Sep 23, 2013
Messages
3,357
So the Woodruff key under the small gear broke again?
Is the keyway damaged?
Does the piston move freely in the bore, rings not hanging up on anything?
 

anonvx

New Member
Joined
Jan 2, 2019
Messages
19
So the Woodruff key under the small gear broke again?
Is the keyway damaged?
Does the piston move freely in the bore, rings not hanging up on anything?
It didn't break again. It just came out. The key way does not appear to be damaged. piston moves fine
 

Will'smotobikes19

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Apr 9, 2018
Messages
1,356
Yeah unless his screw came off the shaft It either partially sheared and started grinding or idk what. All I know is if there's too much slop in the key way it will start "hammering" and won't hold. I think he said it happens when he engaged the clutch meaning he's releasing the lever pretty fast probably. He also said the small gear was spinning freely, it should spin it's connected to the whole rotating mass, crank, rod, piston. Maybe he isn't tightening the screw enough for the gear? sometimes the gears are tricky as they should ideally be flush with the clutch wheel but on most engines they aren't fully seated from factory.
 
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FurryOnTheInside

Well-Known Member
Joined
Sep 23, 2013
Messages
3,357
Yeah unless his screw came off the shaft It either partially sheared and started grinding or idk what.
I thought a too-small key would break or chew up the keyway and it would have to be absolutely tiny to actually escape from under the gear, but I haven't tried it lol.
As blindfolded mechanics we can't assume that the engine ever had a screw holding the gear on. :ROFLMAO:
 
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