Thread: New member Project SL750
07-02-2012, 04:13 PM #1
New member Project SL750
First off I would like to thank everyone for all the help I have found browsing this site!
Back in the Fall I purchased a 94 SL750 for 300 bucks thinking how bad can it be;
I was told the top end was new and it has been sitting since 2004, I thought if the
top end was good I might just be able to replace the crankshaft and gasket kit along
with a good cleaning. WRONG! I should have set it on fire and ran!
I pulled the motor and disassembled.
First thing I found was all 3 pistons were melted In the center, not all the way thru.
After checking the bore in all three cylinders it looked as if it was just punched out .5mm.
Second thing which I expected was the crank bearings were rusted.
The crank was welded and had hotshot rods installed, too bad it will have SBT rods now..
I pulled the trigger and ordered a rebuilt crank and three new pistons along with a gasket
Kit from SBT. Probably should have ordered a rebuilt motor but I like to do my own work.
The build up went well, I installed the motor and did all the fuel lines and rebuilt the carbs,
She fired up with no problems.
Time to check out the pump that was sitting in a box. Junk!! Bearings were rusted and housing
Looked like it was sitting in salt water for a couple years.
I ordered a rebuild kit and coated the stator vanes with epoxy and sanded. Looks good, the
Pump has a skat trak 13-18 impeller that looks almost new and ware ring looks good as well.
The housing will be inspected after a couple runs and will probably need to be replaced. Will see.
Time to install the pump. Dam!! The drive shaft splines are a ¼ gone. I should have looked
At all this stuff before I ordered all these parts! Too late, I cant stop now!
My buddy has a big box of take off stuff from his life as a diehard Polaris fanatic!
I found a good shaft and rubber dampened coupler.
Found the trim motor rusted!! Ebay is my friend!!
While I rebuilt the carbs I didn’t check what jets were in it and I would like to find out why all
3 pistons were melted!! This bothers me!! Off with the carbs, jets are stock and the ski has
Ocean pro vortex f/a. and D & G water box so I ordered 107.5 jets (are these going to be to big?) and a triple line fuel pump.
Hope to be in the water by the end of the week!! So far I have about $1200 into this project, is this
07-02-2012, 06:12 PM #2
- Join Date
- Oct 2006
- Cleveland OH
Welcome to the Hulk.
With the OP FA, DG waterbox, and the 13/18 impeller, stock settings are not going to work, so you kinda need to experiment with jetting. 107.5 mains might be pretty close to what you need. just be casreful before douing any long WOT runs until you sare confident in your jetting. Have you researched piston wash yet?
$1200 is prob the most you would ever get for that ski if you were to sell it, so hopefully it runs well for you and you don't need to sink any more $$ into it.
07-02-2012, 06:45 PM #3
I was reading up on the piston wash and plan on getting one of those borescopes.
How long before I start seeing any wash? would it start to show after 1 tank?
Do you think the stock jetting could have caused the melt down?
Thanks for the help
07-02-2012, 07:23 PM #4
Something interesting I found with the carbs, I couldn’t get the idle under 2900 rpm with the ski out of the water and one of the gaskets was wet the others were dry, I put a straight edge across the carb mounting flange and found the mag carb was not touching the straight edge. I will try to attach some pics, what I did was loosen all the screws attaching the carbs to the rail and ran the nuts on the mounting studs of the center carb agenst the straight edge and then did the same to the other to carbs to bring them in alignment then tightened the rail screws.
07-03-2012, 08:54 AM #5
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