was ready to do first oil change on my crf450 today and just read an article in 12/03 dirtrider mag about making your 4-stroke last. they specifically say "honda crf uses different kinds of oil for the crankcase and the transmission". however when i look at my honda service manual it states "engine oil: honda pro GN4, and others" and states "transmission oil: pro honda HP trans oil, pro honda GN4, and others" Both want 10 W-40 weight. Looks to me like the "Honda Pro GN4" can be used in both engine and transmission.
what is the correct answer?
would I be better off using the "transmission" specific oil for the transmission.