The reason your YZ requires crank (transmission) oil is because the motor and transmission are together as one.
Your TB's motor and gearbox are seperate. The motor itself only requires the oil thats mixed with the gas. The gearbox DOES require oil. The dipstick is on the right side down by the front sprocket.

 

I picked up a 97 Sport 400 about a week ago. I didnt notice a fill hole/plug for the counterbalance. Actually never heard of that so never looked.

Could you please specify its location? Thanks

 

Its to the left and behind the recoil.

It has a large quarter sized diameter "****" with a slot on it .
You need a reeeeal long screw driver or a crow bar with a slotted end to access it.
Look down from the right side of the airbox when seat is removed.



Jim

 

If you ride a 400 you need to check that counterbalancer on a regular basis. Some of them tend to get rid of some oil and some tend to get water in the oil.

Back when I rode them I checked this at least once a week.

These are really good engines and it is fairly cheap to rebuild and maintain them as long as the counterbalancer does not come apart. As long as you have good clean oil in the CB it will never give you any problems.

Let it slide and get low on oil or full of water and it WILL completly destroy the entire engine where it can't even be rebuilt.

It has been my experience that over half of the people that own 400's don't even know they have a CB. These are the ones that have serious problems with the 400 two stroke engines.

 

Very very sound advice. I learned this the hard way. I took lots of money to get it back to running. The water pump seal went out and let water into the counterbalancer cavity and locked up the bearings (bam) just like that. I check it now on a REAL regular basis. But FoQrs you don't have a counterbalancer so not to worry. The only other oil you will have to worry about is the tranny oil.

 

Thanks for everyones help on the 400.