Yamaha Beartracker Gear Case Plug Leak
#1
Yamaha Beartracker Gear Case Plug Leak
Hey everyone I cant seem to find any answers to my problem, hoping for some help. I have a 2004 Yamaha Beartracker 250. I have an issue where my plug (don’t know name) on the middle top back of gear case where the transmission halves merge was leaking. I was actually able to push it down but it comes back up from presssure when engine cranked. The snap ring that holds the plug doesnt look like original but i put an O ring under it to hold pressure and it literally blew the whole plug off from pressure. My question is: is this plug suppose to have a lot of pressure under it like this? And what is the purpose of this plug and what is directly under it to cause so much pressure? The manual or any parts diagram doesnt acknowledge this plug or the snap ring holding it so im real puzzled at all this. I can see oil when plug came out and the oil level slowly goes back down into engine when not running. My PVC valve is hooked up and patent as should be and my gear box vent and hose is hooked up and just freely open to air. No oil comes out of any of the other hoses and this oil leak/ pressure problem has happened with low oil and when engine full of oil. Any help with this is greatly appreciated! Thanks guys! Pictures of plug attached.
#2
Welcome to the forums.
Checking to see what I can find on this for you. I did come across a owner manual you should be able to download for free. Not sure if it's a 2004 model version, but pretty sure a lot of it is the same. I'll try to confirm the year on the manual while I'm checking.
Owner manual.
Checking to see what I can find on this for you. I did come across a owner manual you should be able to download for free. Not sure if it's a 2004 model version, but pretty sure a lot of it is the same. I'll try to confirm the year on the manual while I'm checking.
Owner manual.
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This is what I was looking for. This is the service manual. May be able to tell you what the part is, and what it may need.
Service manual.
Service manual.
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Your second picture shows a big fat breather tube from the cam chain cover, and a smaller breather from just behind the plug you wrote about. Both these breathers take the pressure built up as the piston descends, and blows it into the airbox. Any blockage results in higher pressure in the crankcase, so if the gearbox and crankcase run in the same oil, pressure will build up in both crankcase and gearbox. The breathers have difficulties in shifting 250cc of air out and in, every rev of the crank anyway, so there is a bit of pressure in the crankcase.