Engine Trouble Engine gears grinded each other.

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Hello,
My primary gears are completely grinded up at 200km odo. Engine was in break in period.
The big gear is a bit loose - moves up and down and left-right and it has about 1-2mm of play (that's a cause of damage). I think engine was damaged from factory - it also had damaged thread on clutch flower nut lock-screw and I had to drill it.
The green stuff is a grease which I added before engine installation.

My question is: what is a cause of big gear wobble and how to fix it. I also need to buy new gears.
Thank you in advance for your help.
 

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Hello,
My primary gears are completely grinded up at 200km odo. Engine was in break in period.
The big gear is a bit loose - moves up and down and left-right and it has about 1-2mm of play (that's a cause of damage). I think engine was damaged from factory - it also had damaged thread on clutch flower nut lock-screw and I had to drill it.
The green stuff is a grease which I added before engine installation.

My question is: what is a cause of big gear wobble and how to fix it. I also need to buy new gears.
Thank you in advance for your help.
This normally occures when a bearing is bad and allows to much play(slop) on etheir the shaft or the clutch hub.
 
Thanks for your reply.
So complete disassembly is needed? Are bearings pressfitted?
 
Might be able to do it without a press by tossing it all in the freezer and putting it on the lowest setting. Metal shrinks when it gets cold.
 
wow never seen it get that bad before (note to self grease the bearings in clutch shaft)
 
Note that my 50 cc engine came without the regular clutch center bearings, also the threads on the clutch were 'pre-stripped' out from the factory, so I had to drive out the countershaft/clutch axle and bearings to inspect the clutch shaft.

Since the left bearing and clutch shaft are a light press fit in my engine cases, this was easily done by removing the clutch lever cover ,clutch cover, sprocket and by supporting the left engine case on a 2" deep socket and hitting the loosened clutch axle nut until the clutch was free. My clutch gear has about 1mm free play, but hasn't caused any damage to either the pinion or big gear. I've been giving the clutch a shot of spray can Lithium grease to lube what appears to be a new design of just having no ball bearings at all and a what appears to be somewhat loose tolerance center for the gear ring to ride on. 300 miles so far and no additional wear on the gears.

I would check to make sure your small gear is running without any wobble on the engine shaft, you can trim this up by giving it light taps with a brass hammer on the high spots. It's what Fred does with all the new 'Half breed" ZAE50 crankshaft equipped engines. You will need to pull the pinion gear and reinstall it: check to make sure the toothed washer under the pinion retaining screw isn't buggered. Mine was, it needed replacement.
 
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Hello again.
I cannot remove nut on big gear. It's stuck. I tried wd40, propane torch, I bought 19mm car wrench also. I lock sprocket on the opposite side by hardened steel rod and try to undo the nut by hammering the wrench. Wrench also cannot grab whole nut beacuse it it a bit to thick. So it cams out.
Also this 3 rod contraption in the center can rotate indepently of the big gear.
Can you give me any advice on disassembling it? I have drill stand, angle grinder and bench gridner
 

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Keep in mind there was a bad batch of small crank gears a while back that were not hardened from the factory. They were shinier than the normal ones, and if you ran a file over them you would see shavings. On a hardened gear it won't do that.
 
it's sad but lots of the small pinion gears were not cast on center. like 1000's of them but not many ppl mentioning it for months. I think you can get the pinion gear really cheap
 
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