89rz350

It's a kind of wining noise, it's strange that it's happening only in 6th gear ... looks like there's too much backlash of something like this. First I tried to use yamaha transmission oil 10w30, the noise was there, I was experiencing clutch slip and it was hard to shift into 6th gear. Now I'm using motor oil 10w30. No more clutch slip, the 6th gear is easier to shift when the oil is colder but the noise is still there. For the oil temp when I mean cold it's room temp. When warm it's like after 15 min of riding. It looks to me that the problem is between the cases and need to put the engine appart. Does anyone ever had problems such like this ? Thanks !

Hi guys ! I'd like to know if anyone already experienced this problem, there's a straight gear type noise only in 6th gear. It doesn't seems normal. It's on a Rz350, I bought the bike and I didn't have the road to ride it in 6th gear and I tear the bike appart to make my project bike. I rebuild the engine but i didn't touch the transmission guessing everything was fine. When I inspected the gears everything looks ok. During my road test I also realized that the 6th gear is harder to engaged when the oil is cold. Now I think I need to dissasemble the engine again ... can anyone help me ? Thanks !