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2001 Seadoo Sportster LE. Just got it!

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Ok. I will push the pin out of the pistons tonight and bring pistons and cylinders to the dealer first thing in the morning.
Got a conference call tonight. If I cannot make it I think I still bring the cylinder to the dealer in the morning.
Here is some pictures inside the cylinder. They are not super smooth at those lines.
541.jpg


542.jpg



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Bonmotwang said:
Are those cross lines from the bore bar?

Edit: also the base gasket has 5 holes.

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Click to expand...

Those are from a finish hone, used after the boring bar. The purpose is to create a crosshatch pattern in the cylinder to retain oil in order to assist your rings initially seating to the new bore.
 
Did a quick measure with my caliper.

Top of the cylinder max measurement: 87.95mm, 87.90mm

Flip over the cylinder
Bottom of the cylinder max measurement: 87.90mm, 87.88mm.

According to the manual, cylinder is tapered by 0.1mm max.
My cylinder tells me the top is bigger than the bottom. Is it true?

Moving around the caliper for biggest measure for ID, couldn't get the reading over 88mm.
Based on the pitting and score condition (cannot catch figure nails), Is 0.25mm more than enough to get it straight?

Based on stock number 88.00mm, these cylinders have not ever been bored.

Then the piston must be stock too.

So my question is how come the stock piston crown diameter is 87.25mm which is 0.75mm small than the cylinder?
It is the ring stopping the piston from dancing in the cylinder? or "dancing/wiggle" is legal?
According to the inspection tolerance in the manaul, piston/cylinder wall clearance should be less than 0.2mm (0.09mm new), so the skirt must be bigger than the crown?

And this tells me for the piston: the top is small than the bottom?
 
Bonmotwang said:
According to the manual, cylinder is tapered by 0.1mm max.
My cylinder tells me the top is bigger than the bottom. Is it true?

Moving around the caliper for biggest measure for ID, couldn't get the reading over 88mm.
Based on the pitting and score condition (cannot catch figure nails), Is 0.25mm more than enough to get it straight?

Based on stock number 88.00mm, these cylinders have not ever been bored.

Then the piston must be stock too.

So my question is how come the stock piston crown diameter is 87.25mm which is 0.75mm small than the cylinder?

And this tells me for the piston: the top is small than the bottom?
Click to expand...

The top of the piston expands as it reaches operating temp, this is why it's normally tapered and probably now it is worn more than the skirt area as well, just as the bore at the top is worn more. This is b/c there is not as much oil in the top of cylinder as the bottom, and the temps are higher there as well.

So normally the piston is tapered, to allow for heat expansion.

These precise measurements are not within the capability of most home garage mechanics IMO, these are CNC machined in the ROTAX factory and the expansion rates of the alloys are calculated precisely during the design phase.

That cylinder liner is rather ugly!
 
Are those puddles of aluminum at the chamfered lower edge of the liner?

Even the choice of metals is not arbitrary, the piston and cylinder liner materials must be chosen to avoid galling, thus they cannot be made from the same material. I really would have liked to see these motors made with nikasil plated liners(rust proof and wear proof) but ROTAX may be saving money and I'm sure there are various other reasons.

http://en.wikipedia.org/wiki/Nikasil
 
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Sportster-2001-951C-Stock said:
Are those puddles of aluminum at the chamfered lower edge of the liner?

Even the choice of metals is not arbitrary, the piston and cylinder liner materials must be chosen to avoid galling, thus they cannot be made from the same material. I really would have liked to see these motors made with nikasil plated liners(rust proof and wear proof) but ROTAX may be saving money and I'm sure there are various other reasons.

http://en.wikipedia.org/wiki/Nikasil
Click to expand...

Yes. good eyes! they are hard metal puddles.

So the the scoring happened at the liner!?

PS. Just off the phone with red ears. Good meeting. So business is taken care of, back to the side business :-D
 
Waterluvr said:
That's your pistons melting, and you found it before it destroyed your engine. Gold Star award for you! :)
Click to expand...

Nice. I like gold stars :-)

I will have time in the morning to visit the ex seadoo dealer and bring the cylinder with me.
I will ask him to use the dial bore gauge to check it and give a firm lead time and price. (he said if the bore size is too big he has to order parts in).

I should ask him to trim the rave blade too, just to stay at the safe side?
 
Sportster-2001-951C-Stock said:
Are those puddles of aluminum at the chamfered lower edge of the liner?

Even the choice of metals is not arbitrary, the piston and cylinder liner materials must be chosen to avoid galling, thus they cannot be made from the same material. I really would have liked to see these motors made with nikasil plated liners(rust proof and wear proof) but ROTAX may be saving money and I'm sure there are various other reasons.

http://en.wikipedia.org/wiki/Nikasil
Click to expand...

I think it's primarily because there's no boring one, and Iv'e seen my fair share of expensive air cooled Nikasil saw cylinders relegated to the bin on account of heavy scoring in the plating with pretty short run times. I was able to save a few with 320 ball hones but most were junk at that point.
 
Waterluvr said:
Me to, I'm not sure if our friend fully understands the timing of these things and he really has gotten into this just under the wire. Not to many more full throttle planing events left in that top end before the odds go the wrong way.
Click to expand...

:cheers: and :thumbsup:

Wow, these little puddles will cause troubles in the crank case? I guess at high speed, little things become big.

Back to theoretical part (with some evidence)
What is the cause for this scoring and puddling?
- Screw settings were to lean?
- Air leak at the PTO carb seal?
- Wrong oil (blue color) used by PO and PPO and PPPO?
- Overheating, but it links back to lean right?
- Cooling system? is it possible the water intake blocked by weeds?
 
Bonmotwang said:
Nice. I like gold stars :-)

I will have time in the morning to visit the ex seadoo dealer and bring the cylinder with me.
I will ask him to use the dial bore gauge to check it and give a firm lead time and price. (he said if the bore size is too big he has to order parts in).

I should ask him to trim the rave blade too, just to stay at the safe side?
Click to expand...

Yes, for my motor I want the maximum tolerance for clearance in order to allow for any unusual wear. I'd turn beat red and say bad words if the Rave's ever took out the rings in my motor. In my minds eye, if the pistons and rings are growing then the Raves need to be trimmed accordingly even if it's the first over bore size.

I'm surprised that shops don't insist on just doing it as part of the service when they bore the sleeves.
 
Bonmotwang said:
:cheers: and :thumbsup:

Wow, these little puddles will cause troubles in the crank case? I guess at high speed, little things become big.

Back to theoretical part (with some evidence)
What is the cause for this scoring and puddling?
- Screw settings were to lean?
- Air leak at the PTO carb seal?
- Wrong oil (blue color) used by PO and PPO and PPPO?
- Overheating, but it links back to lean right?
- Cooling system? is it possible the water intake blocked by weeds?
Click to expand...

Yes Sir, those little puddles cause the destruction of the entire bottom end of the motor when that material makes it into the crank bearings and oil windows of the rods.

Air leak lean condition for sure thanks to one gasket being improperly installed and in my opinion the rest of it is very normal wear and tear from nothing more than normal use. The visible wear patterns in you top end are very consistent with having enough hours put on it to warrant a tear down and rebuild.

Nothing in there looks like it failed prematurely to me at all. Welcome to 13 years later on a motor that routinely see's 7000 rpms.
 
Waterluvr said:
Yes, for my motor I want the maximum tolerance for clearance in order to allow for any unusual wear. I'd turn beat red and say bad words if the Rave's ever took out the rings in my motor. In my minds eye, if the pistons and rings are growing then the Raves need to be trimmed accordingly even if it's the first over bore size.

I'm surprised that shops don't insist on just doing it as part of the service when they bore the sleeves.
Click to expand...

This just remind me one thing I noticed when I was disassembling the RAVE and putting them together:
The plastic piston will screwed on the slide blade. But I when took it apart, it was not even finger tight. Then I was thinking, oh, not big deal, it has so so many threads to hold it and it does!
But when I put them together I realized that if it is not all the way screwed in, the RAVE is more into the cylinder, isn't it?

But in my case, the blades looked OK.
 
Waterluvr said:
Yes Sir, those little puddles cause the destruction of the entire bottom end of the motor when that material makes it into the crank bearings and oil windows of the rods.

Air leak lean condition for sure thanks to one gasket being improperly installed and in my opinion the rest of it is very normal wear and tear from nothing more than normal use. The visible wear patterns in you top end are very consistent with having enough hours put on it to warrant a tear down and rebuild.

Nothing in there looks like it failed prematurely to me at all. Welcome to 13 years later on a motor that routinely see's 7000 rpms.
Click to expand...

Ok, that should make me sleep well tonight.
I am covered the crank case opening with paper towel right now. Do I need to vacuum it before I put on the new top end :-D
 
Waterluvr said:
Yes, if the threads aren't tight when it opens you create additional length to the blade end. Good catch on that!
Click to expand...

Yes, and back to your point, why increase the cylinder size without backing of the blade to keep the SAME clearance?
They must think everything else is still in "factory tolerance" :-D
 
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