View Full Version : 787 balance shaft oil

robin savell lloyd
02-24-08, 08:30 PM
I was reading one of seadoosnipe's post about the 787 balance shaft oil. I have never seen this before does this shaft have a place were oil can be added from out side the engine or is this something you can only do by taking the engine apart. if the lattter is true I am not sure if I would like that type of engine. I allso read somewhere else that one of the bearings is a sealed bearing with grease in it. I am not in dout. it just sound unusual for an engine. I just have never seen one like this before.

02-24-08, 08:53 PM
Looking from the back of the engine, the balance shaft is on the port side of the engine. You can see the outline of the balance shaft through the casing. Near the back of the balance shaft (PTO side), you'll see a small plug. That is where you add the 1 oz of SAE, 30 weight engine oil. But this oil is only necessary during an engine rebuild. You should never have to re-fill that oil. It's not even listed under routine maintenance as being there. It only serves a small purpose to the roller bearings of the shaft. I have never had or heard of anyone ever having a problem with this design.
I might also add, that I wasn't the one who brought this to light in the forum. When it was first posted, I don't remember by who, I thought they were off their rocker. Then, I believe DAWG made the discovery that it was a fact. I have since researched it and now understand it's function.
It truly isn't something we should have to worry about, unless we do a rebuild. Even if the engine floods, it isn't stated to re-check that oil in the "flooding" procedure.

The "zirc" fitting for the rotary, although I don't have any hard core research to support it, I'm against the idea of it even being possible. Let me tell you why. We have grease (zirc) fittings on mechanical products all around us. The only time I ever see the grease fitting in service, is to lubricate a roller bearing. The rotary chamber, which is suppose to be flooded with the 2-cycle oil, is a worm gear. I've never seen a worm gear lubricated by grease. So for me, I don't think this is a suitable substitute for the oil. I do not approve of that procedure. I only hope who ever that was that purchased this engine in this type configuration, can take care of it, and hope that there hasn't already been damage to the shaft.

robin savell lloyd
02-24-08, 09:02 PM
i do agree. i did notice you said the oil tank should be left in the ski if bypassing injection. I heard from racers this is not good because you can get air in oil line if rolled over, but a boat is ok because you do not roll it over hopefully.

02-24-08, 09:22 PM
I'm not quite sure how the injection tank set-up is designed in the skis, but I will assume, that it's close to the same design as the boats. Not to sure about gettnig the air in the lines, don't think it would matter if you've blocked the injection system off and using premix. The air bubbles in the line would only affect the use of the oil mixture in the fuel. To the rotary chamber, it wouldn't matter. If the boat went upside down and the oil in the rotary chamber was able to drain out, when the boat was righted again, the oil would drop back into the chamber. It's only used there for lubrication, it's not burned there.
Since we are talking about oil and blocking off or close to it. Doing premix isn't for all Sea-Doo engines. The DI motors need the oil injection because to block off the injection lines and go with premix would take away the lubrication of the rotary valve. On the DI motors, there is only air through the induction of the rotary valve and the oil and air lubricates the crank and bearings before mixing with the fuel for combustion. I also cite DAWG for that discovery......:cheers:

robin savell lloyd
02-25-08, 08:15 PM
decide for your self if info is usefull

02-25-08, 09:13 PM
I have seen that before on seadoo source before...I think it is a good idea.