Reply To: Crankcase Assembly Discussion

[Don]

Like Bill says, the primer is not necessary, unless you are planning to fire up the engine that same day…. But, I would only apply the sealer to one side of the block. I would apply the sealer to the crankcase cover half only because the crankshaft isn’t in the way. You must be very careful with the sealer, you don’t want to plug any passages or have it ooze into a bearing. A tiny dab of the needle bearing grease around the bearing cages and passages will keep the sealer out of these areas. Again, this is such an important operation that you want to take time doing. Too much sealer will plug up passages, get into bearings, and may actually shim the halves apart slightly. Improper prep, or not enough sealer will result in the dreaded external leaks once the powerhead is fired up…

Theoretically, the rod screws should be replaced, but that seems like an extreme safety precaution. Those screws are hardened, and breaking them is highly unlikely. But, if I had pulled a powerhead apart that had been exposed to some questionable work previously, I would probably replaced the screws. Make sure the fracture joints line up properly before assembly…If you can’t get the rods to line up satisfactorily, this usually indicates someone has been in there before, and tightened the rods when they weren’t properly oriented or aligned. Like Bill says, use only some two stroke oil on the rod screw threads on this style rod.

The only other thing I will add is to determine whether or not an oring is used on the upper bearing of this engine. This may be one of the engines with that crazy recirc system that draws the oil away from the bearing/seal where the oring is not used. Check all the passages to ensure this system will work properly, you sure don’t want oil all over the points.