Gearbox bearings

[Primax]

OK Jibber, how many guesses do I get!

[dzl]

Thr XTZ660 and the last of the 4PT XT600's did get the best/ widest of the 5th gears of all the XT range with the 3YF fifth gear. The rest of the gears same as rest of XT's. In theory 5th gear may last longer in these. In reality any big bore thumper that does lots of kms is going to have gear wear/ pitting issues not just XT's. DR650's which are used in the same manner also have the same issue. The transmissions in these bikes have a tough life with big shock loads due to the nature of the type of engine. Lugging the engine/ poor oil quality/ overheating will accelerate the wear. Better to open engine up and repair what is causing noise as the bits of metal breaking off can circulate and cause more issues and damage. Plenty of info on this in other threads here.

[jibber]

What he said, there have been failures through the whole range

[bum bum]

Would metal shavings show up in the oil filter?

[Primax]

dzl, thanks for the insight.