MontegoMan's Water Toys are Laughing at Him!

"MontegoMan562 is a Capri RS Owner" (montegoman562) 06/26/2019 at 11:17 • Filed to: fanny, fanny pack, TheFannyPackDuo, polaris, SLT 780, Top End Rebuild, boatlopnik, PWC, Jetski, jetskilopnik

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Remember when I started the last post out with them being fixed “For now. ”?

Ha. Hahahahaha. The Fanny Pack Duo mocks me.

The Polaris (aka Fanny) needs a top end rebuild. I just got around to the compression test on it last night. When I did the test when we first bought them it was at 120, 120, 70. I knew it wasn’t great. I also mentioned in the last post that my wife told me the warning light was blinking which is what led me to do another test.

This time it was 120, 100, 50. So I’m going to do the top end before I have to replace the whole motor on this one. As of now Fanny is in dry dock until the repair is complete.

It’s just under $400 for a new complete top end from SBT (SBT is the leader in PWC engine parts and who I got the motor for the Yamaha (aka Pack) from). The only question now is .5, 1.0, or 1.5 overbore. No price difference and it’s all coming as a clean set of new cylinders and pistons that match each other. I’m also going to be doing the oil block off kit on this one when I do the top end to remove the risk of a random seized oil pump destroying my investment.

To keep you updated on the story so far from most recent to oldest :

vondon302 > MontegoMan562 is a Capri RS Owner 06/26/2019 at 12:09

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Lol 

shop-teacher > MontegoMan562 is a Capri RS Owner 06/26/2019 at 12:12

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Sounds about right :)

Pickup_man > MontegoMan562 is a Capri RS Owner 06/26/2019 at 12:17

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Two trains of though, especially since these are new pistons and
cylinders.

1. Small overbore. Pros - room to have it bored again in the future, likely zero carb tuning due to extra displacement, slap it on and go. Cons - Can’t really think of any.

2. Large overbore. Pros- more displacement = more power. Cons - no room for boring in the future, a worn out top end requires a whole new top end again. Will possibly have to tune carbs/injection for larger displacement, which adds cost, time, and frustration.

If a stock bore kit isn’t available, I vote for the .5 over. 

MontegoMan562 is a Capri RS Owner > shop-teacher 06/26/2019 at 12:48

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Hahahaha. I’m in no way surprised.

MontegoMan562 is a Capri RS Owner > Pickup_man 06/26/2019 at 13:06

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This sounds like wise advise. The difference between the kit coming with new cylinders (aka jugs, they are individual cylinder units, not a full block on this if you aren’t familiar) is 30 bucks. Which means I see literally zero advantage to not replacing the cylinders with this rebuild. Stock isn’t available through SBT. .5, 1, or 1.5 were my options. I’m guessing because they probably get back people’s core exchange cylinders and promptly bore then to .5 to make sure they’re clean to send back out to people.

The power is tempting. It’s a BIG ski, official length is 10 feet, but I think it’s a bit longer.

Maybe I’ll go in the middle... at 1.0

Pickup_man > MontegoMan562 is a Capri RS Owner 06/26/2019 at 14:14

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$30 extra for a matched set of jugs is a steal, boring your current jugs will very likely cost more than that, plus you’re out the extra time that they’re in the machine shop.

I’m not really sure what kind of power you’d really gain, some quick math will get you the gain in CC’s though. If you’re just after a fun toy and not outright performance I’d still stick with the smaller size.