787 Bottom end Rebuild

[rancher2021]

I have a 96 gtx with the 787 engine. It ran really great untill the engine seized. I took it to a dealer and they told me that the bottom end needs rebuilt. I guess some bearing in the bottom end went bad. I have some mechanical skills and am wondering if this is a rebuild that I can do or if I need to take it to a shop. I would much rather do it myself and save on labor charges form a shop, but that is dependant on the level of difficulty in rebuilding my engine. What tools are needed, are there any tricks, and any other information would be very helpful. I have also considered buying a rebuilt engine online but am unsure if this is a good approach. If anyone has been here or has a good idea drop me a line. Thanks.

 

[SabrToothSqrl]

well

I've never done a 787, but if your doing to redo the bottom end, adding a top isn't a bad idea or really any more work...

If you buy a rebuilt one then you can also get a 1 or 2 year no fault on it, adds peace of mind, and you know it's built 'right'.

I send all mine out (951s), I like the warranty!

But it's going to be cheaper if you can do it yourself...

 

[seadoosnipe]

Rancher, the 787cc is a fairly easy engine to work with. There are only two items that have to be strictly adhered to. The timing of the balance shaft and the rotor plate. The ignition timing is hard set, so you really don't have to worry about that part of it.

My biggest issue with members who have an engine lock up is, they sometimes fail to find the root cause of the failure, put a lot of money in the rebuild, to only have a 2nd failure. From your description, it seems you lost a lower crank bearing. This can be caused by a few things, but the number 1 primary cause is usually due to a problem with the oiling. The next biggest problem is a bearing going from normal wear.

There are online shops that specialize in the rebuilds your asking about. If you have some mechanical skill, a torque wrench and specs from the shop manual, you can probably do this yourself. I use SBT for my kit parts and use Seadoowarehouse.com for purchase of the individual parts. For instance, I had an oil pump let go, cause a failure in my MAG piston bearing. I bought the lower end from SBT but bought my oil pump from Seadoowarehouse. SBT only specializes in pumps and motors, they don't sell many of the individual parts.

You'll hear pro's and con's about SBT, here in our forum. But, in my experience with SBT, I've only had one issue with them in the past 7 years. It's in my opinion, that those who have horror stories to tell about SBT's customer service and quality of rebuilds, are ones that didn't find the root cause of their blown motor, then blew the one they got from SBT, thinking it was their engine that was faulty, when it could have been an oil pump, carb or a problem with any of the parts that doesn't come with a newly rebuilt engine.

If you choose to go that route, it'll cost you about $600 bucks, by the time your finished. Sometimes, you have to weigh the cost of doing just a bottom end, verses doing a complete motor swap.

Good luck, let us know how you come out. You can also look at my thread, "a look inside the 787", in the 2 stroke boat section, or click on the link in the bottom of my signature. That might acquaint you with the internal parts.