08-31-2010, 05:05 PM #1
- Join Date
- Aug 2008
2000 Yamaha SUV 1200 Rebuild or buy shortblock?
My buddy Has a 2000 Yamaha SUV 1200 that has blown a piston. the ski has been used almost every day during the winter months here in Hawaii, once a week at minimum. It has at least 600 hours on the stock motor. Recently he noticed it had no power. We did a compression check & the readings were 0-20-20 if we can trust my compression checker. We pulled the head off & found that the piston closest to the back of the ski has a small chip out of it. it appears that it over heated, there is some sand packed in around that cylinder wall where the cooling water goes. There is a lot of corrosion around the cooling chambers. The bad cylinder wall has scratches that you can feel with your finger nail but not that deep. the other 2 pistons seem to have some play in them but look good. The head has 2 small pinhead size dings like a nail poke in it on the bad cylinder, the other 2 look fine. See Photos attached.
Our questions are... 1st should we do a complete rebuild including crankshaft bearings etc. or just replace all three pistons & rings & have the cylinder walls bored or honed.
or 2nd just buy a short block from SBT or comparable dealer,
or 3 buy a used 1200 motor from someone on this site that has a low hours lake used ski??
If we were to do a rebuild what would you guys recommend doing.. Do I need to have anything done to the crank or case?? what should I do about the cylinders, who does this kind of work, Is the head OK & reusable. Who makes a good rebuild kit that would come with all the pistons rings bearings etc..
P.S due to all the corrosion we are wondering if these ski's have any type of zinc plate which would help cut down on the electrolysis & Corrosion inside the motor.
Mahalo, & thank you for all your help.
08-31-2010, 10:41 PM #2
- Join Date
- Jan 2006
- Texas City, Texas
Well, you certainly got your money's worth out of that engine!
IMHO you should go for a total rebuild which would include new pistons rings, wrist pins bearings, seals, gaskets and at least a rebuilt crank. (There is no use having a strong top end with a crank that has 600 hrs on it). The head and cylinders are reuseable, but will have to be cleaned up by some one who knows what they are looking for. You should not have any trouble finding someone on the islands that can put a 65U engine together.
You will also have to take the time to go through the cooling system (pump, hoses, and exhaust pipe) to make sure that there is no sand/dirt in them that would reduce or inhibit your cooling.
There is a lot more to putting the boat back together, but I hope I have you thinking along these lines.
09-01-2010, 12:22 AM #3
- Join Date
- Sep 2009
- Grass Valley, CA
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