gearbox, second gear tooth loss

[tea5ive]

Went for first test ride after a full engine rebuild. After about half a mile going downhill nice and steady the back wheel locked up pulled in the clutch thinking it had seized it , but the engine was still running but back wheel still skidding. Anyway after I got it stopped and bit of rocking back and forth in got it rolling again. So back to garage for a gearbox strip down. 2 teeth missing off second gear and the two teeth found in the bottom of the case. Never known second gear failure before, main cluster seems okay no damage. Gearbox is an Li125s any one seen this before?, maybe it can't handle the power of my home tuned 185 lol.

[rosscla]

Anything else loose in there?

We're you in 2nd or changing into 2nd when it went? If not then it shouldn't really have been loaded.

[tea5ive]

Anything else loose in there?

We're you in 2nd or changing into 2nd when it went? If not then it shouldn't really have been loaded.

No, I was in top mech down hill going steady. I was thinking the same about the changing into 2 nd which would give you a reason for the failure, not unless when going up the gears the damage was done but maybe only cracked the teeth then they let go and bit further on??. Luckily I had 12 yes 12 spare second gears for the Li125s/gp125/200 gearbox lol

[vespanic]

Quite a few years ago on a mildly tuned engine with a cryogenic frozen gearbox I had teeth break on the second gear. Same gearbox as yours. Had been running engine for at least a couple of years. Never found out why.

[rosscla]

50 year old metal....do you need another reason?

[vespanic]

50 year old metal....do you need another reason?

[tea5ive]

will be going for another test run today after the gearbox rebuild, wish me luck