Just wondering if anyone has had a similar experience with xr? I purchased a 02 xr 400 from my brother in law a year ago. He kept it in really good shape always changed the oil religiously using Hondas semi synthetic oil. Before my last desert trip I wanted to do an oil change and bought some Honda gn4 standard oil, the same oil I've always used in all my older xrs. Right after I changed the oil my brother in law saw the container and told me he's always used Honda semi synthetic. I talked to a couple people who said I should be okay. Now a half hour into the first ride I notice some clutch slippage that wouldn't go away. The bike does have a few thousand desert miles on it, but it seems like to big of a coincidence that the clutch starts slipping after the oil change. But maybe I just didn't notice because it slowly got to this point. Hard to tell. Can going from semi synthetic to standard gn4 cause this, or was it time for new clutch plates and springs? Also, if it was the oil, did I do unreversable damage or can simply changing back oils do the trick. Probably 1 hour of trail riding after it started slipping slightly at high rpms.