Hi, I realise the posting about small end beaeing/bush was a few posts back, I just thought I'd throw this in. In my opinion that the small end bearing is the weakest link in a 66cc China girl, but I'm with Bairdco on this. Upgrade the bearing to a quality, wider bearing rather than a bush, especially if u r going to try extracting higher performance from ur motor. Use a 10x14x15 or a 10x14x16 bearing to prevent axial drift as the pin bosses in the piston r too far apart, allowing the bearing to drift like a quarter out of the rod either side. A bush is ok for a stock motor but not so good if u want more power. The reason is that a 2 stroke (uniquely) loads this bearing uni directionally. The pin is always being pushed towards the big end side of the small end & doesnt unload thrust in that direction. I found out abour this when I got an RSE billet head & they said to make sure the motor had a bearing, not a bush there or it would fail. So, I did some research, reading Jennings etc to find out more about. The afore mentioned reason was wot I found. The more power u extract from the motor, the more forcefully the small end is loaded in this direction, meaning more chance of the lubricant film breaking down if u use a bush. Hope this helps. Cheers
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Hello, I know this post is old but...this might help you or future others 
I took a Quarter, good old twentyfive cent piece. Fits in the Flat head slot on the gear. Took a extra large adjustable wrench and tightened on the quarter with vice grips. Use a penny to jam the gears from rotating. The gears will be fine and crunch the penny a bit. Get some progressive leverage that way and or tap wrench with a BFH. Mine came right out. If anything gives first it will be the coin and wont mess up the slot. Give a light coat of grease to the gears before you put it back together. Take care NOT to get any grease inside the clutch cuz it will slip. When your in there, its good to inspect the clutch pads. Make sure they are clean and dry. They can all be flipped over to get more life out of them if they are worn. Good luck!
I took a Quarter, good old twentyfive cent piece. Fits in the Flat head slot on the gear. Took a extra large adjustable wrench and tightened on the quarter with vice grips. Use a penny to jam the gears from rotating. The gears will be fine and crunch the penny a bit. Get some progressive leverage that way and or tap wrench with a BFH. Mine came right out. If anything gives first it will be the coin and wont mess up the slot. Give a light coat of grease to the gears before you put it back together. Take care NOT to get any grease inside the clutch cuz it will slip. When your in there, its good to inspect the clutch pads. Make sure they are clean and dry. They can all be flipped over to get more life out of them if they are worn. Good luck!
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