as long as it doesnt have any lubrication additives in it, it will work for the trans. however, yamalube trans oil has a no foam characteristic that stops frothing and thinning of the oil. also proper 2stroke gera oil has better shear resistance, in other words it holds up to being cut by the gears better therefore offering better gear tooth protection.
anti friction additives like in some engine oils will affect clutch grip and or release.
use proper transmission oil if possible, otherwise straightforward engine oil with no friction additives will be fine