96 GTX top end rebuild question

[BachelorF16]

Just rebuilt the top end of my 787 motor with a SBT kit and am trying to get the motor dialed in. While doing a post run check on the ski, I noticed a hissing soud (air leaking)when I wiggled the grey electrical connector that goes into the front of the motor (mag side). My question is this: Is some pressurized air in this compartment normal after running the motor for a few minutes? It doesn't seem to have a whole lot of presure but it definitely leaks air when I wiggle the connector (and only when I fool with the connector, otherwise no air noise). Maybe I am just paranoid of blowing the motor again and am looking too hard at everything. Thoughts anyone? Thanks.

[dsolie]

Re: 96 GTX top end rebuild question

There is no pressurized air in there. In fact, it should be an airtight assembly. Does it make the same noise with the key on and off?

[BachelorF16]

Re: 96 GTX top end rebuild question

Yes, after shut down there is definitely air in the compartment, not a bunch but I can definitely hear it leak out if I mess with the grey plug that goes into the magneto compartment. I heard from a tech at SBT that a little air is OK but my other 96 doesn't have the same problem and I am concerned about it.

[BachelorF16]

Re: 96 GTX top end rebuild question

Also, does anybody know how much trouble it is to replace the front crankshaft seal if it comes to that? Thanks.

[dsolie]

Re: 96 GTX top end rebuild question

Pull the motor, PTO, flywheel, and housing. Separate the case halves, replace...

Pretty much a PITA

[BachelorF16]

Re: 96 GTX top end rebuild question

Dan, thanks for the answers. I have run the ski for the break-in and it runs great (after getting the carbs dialed in). Still have the slight amount of air that will leak out if I mess with the gray connector going into the mag compartment but the ski doesn't seem to care. Spark plugs are a perfect chocolate brown so I don't think I have a suction leak into the crankcase at all. Just wanted to follow up on this for the forum folks that might go to school on all of this.

Ken