premature bevel gear wear - what's causing it?

brens_gbikes

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i've got maybe 400 miles at most on this engine. what's causing this thing to wear out so quick? anybody had this problem and fixed it? or should i stock up on bevel gears ......

my crank isn't balanced and i never cracked the bottom end when i put it together. maybe the clutch or crankshaft are sloppy and wobbling around?

i've noticed the teeth on it getting sharper for a while. i've greased it a few times but it doesn't seem to do a lot, the grease just gets flung all over the clutch cover.

i just fixed the back wheel last night (broke half a dozen spokes a few weeks ago) and went on a test rip, half way through it let go. the sound was very bad, lol. at least the wheel is working well enough.
 

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Did you put grease on the gear ? Your suppose to grease it

Or it's a defective gear and wasn't heat treated properly
Get a New Gear
yea i greased it a few times but it didn't help much. i just ordered a new one on amazon. actually i ordered 5 of them lol. a 5 pack of it for 20 bucks aint bad. just in case it's a recurrent problem. probably easier to just keep spares. the clutch bevel gear teeth seem totally fine so your defective idea would make sense. you'd think if it was a mechanical issue that both gears would be worn down
 
yea i greased it a few times but it didn't help much. i just ordered a new one on amazon. actually i ordered 5 of them lol. a 5 pack of it for 20 bucks aint bad. just in case it's a recurrent problem. probably easier to just keep spares. the clutch bevel gear teeth seem totally fine so your defective idea would make sense. you'd think if it was a mechanical issue that both gears would be worn down
A gear that's hardened properly won't wear out

BTW just a dap of grease because ya don't want it flinging all over the place
 
yea i greased it a few times but it didn't help much. i just ordered a new one on amazon. actually i ordered 5 of them lol. a 5 pack of it for 20 bucks aint bad. just in case it's a recurrent problem. probably easier to just keep spares. the clutch bevel gear teeth seem totally fine so your defective idea would make sense. you'd think if it was a mechanical issue that both gears would be worn down
The clutch gear was hardened and the little bevel wasn't and the big gear had the little one for lunch.

If you put a big screwdriver between the case and the little gear, can you lift up on the gear any? Maybe the crank bearing wore out. Is that an eBay engine?
 
I recall a few months ago there was someone who had this issue, but he was too impatient to have his issue resolved and the thread went no where. Maybe your crank is out of true and the gear has a wobble in it
 
When something is over stressed then replaced with a strengthened part, the next weaker thing down the line is the next to go.

Even if both gears are the same hardness the smaller one will wear out first. The reason being is there's 82t in the large one and 20t in the small one. So the smaller one's teeth are being used 4.1 more times than the larger one.

The cause of the wear is due to excessive stress being put on it. For example: such things as using something like a 36t rear sprocket while trying to climb steep hills. Things like not using enough pedal assist on take offs etc.
 
This pic is a little out of focus and closer in would have been nice. Am I seeing this..........it appears to me that the teeth are not making total conatct, like only half a tooth. Not much you can do about something like this.
 
The clutch gear was hardened and the little bevel wasn't and the big gear had the little one for lunch.

If you put a big screwdriver between the case and the little gear, can you lift up on the gear any? Maybe the crank bearing wore out. Is that an eBay engine?
the motor is a zeda 80 that i put together in like november. so i can't see the bearings being bad in just a few months and a couple hundred miles. but i guess it's not impossible if the crank is way out of whack, which maybe it is, since i never opened up the bottom end. i'll check it out tomorrow.
 
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