Got a New baby. 1997 SPX

[Bonmotwang]

Yes, it accelerated with many many G's when I hold on the throttle from idling.

OK, I can sleep well now :-D

But still hanging on understanding and learning about the 2 strokes since there is no sign of hope to bring the ski out one more time this year.

I posted my questions in the picture about the fine machined lines on the piston.

 

[Bonmotwang]

Dang! That's some rust and some nasty nasty raves

The rubber is very soft. seems like no elasticity, comparing the ones on my 951.
Is it normal or I need to replace this 17 years old rubber?

Looks like I am setting up my second shoping list :-D

 

[Bonmotwang]

That motor is probably the second strongest untouched all original 787 left anywhere, you saw number one in a boat bilge when you visited There might be more out there, but I haven't seen any.

Don't lose any sleep that exhaust scoring is so light there's no loss in performance yet, you'll get plenty of hard use out of that engine before it's time to break the glaze on the cylinders with a hone and wake it back up with a set of standard size pistons and rings and you'll be doing that right at home, no machine shop needed.

Man, I was a little upset and also more excited about I am into a rebuild of 787 engine. LoL

Well, because I need to sleep well, I have no extra time for the rebuild :-D.
Maybe next time. Find a stuck new FULL BORE engine as yours for my project.

 

[Waterluvr]

Man, I was a little upset and also more excited about I am into a rebuild of 787 engine. LoL

Well, because I need to sleep well, I have no extra time for the rebuild :-D.
Maybe next time. Find a stuck new FULL BORE engine as yours for my project.

Disclaimer required, that was not FULL BORE's fault and was nothing more than a ring that stuck and broke on account of someone being to cheap or lazy to make use of a can of fogging oil, the cylinders still had water in the bottom of the jackets amazing there wasn't freeze damage. That engine was bone dry when I pulled the head, not a drop of oil on the liners anywhere in there and it sat like that all of the previous winter and this summer.

I was lucky a light honing cleaned it up so well, that took next to nothing to make it right again.

 

[Bonmotwang]

The rubber is very soft. seems like no elasticity, comparing the ones on my 951.
Is it normal or I need to replace this 17 years old rubber?

Looks like I am setting up my second shoping list :-D

The bellows are full of black oily stuff. I guess this is normal because the exhaust directly goes into the bellow to push the blade open?
It should show a good seal if I block that small hole, right? The rubber seems to be ok, doesn't see any cracks or holes.


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[AdamXP800]

Did my "usual" piston inspection. A little surprised by what I saw:
MAG piston looks ok. PTO side has a lot of lines, not like the lines i found on the 951 in my boat.
The rings are not seized, I used a screw driver to push them, they moved a little.
You can see in the picture, looks like the white stuff is white paint??!!
MAG side :
View attachment 28013
View attachment 28014
View attachment 28015
PTO side:
View attachment 28016
View attachment 28017
View attachment 28018

More work for winter :-D


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Waterluvr, you're saying this scoring is nothing to worry about?

I've seen a engine with 150/150 compression before ride take of and 5 minutes later be doodoo compression from lean runs from tempo lines,oil filter gunked and from brittle oil lines/cracked OEM painted oil lines.

 

[Waterluvr]

Waterluvr, you're saying this scoring is nothing to worry about?

I've seen a engine with 150/150 compression before ride take of and 5 minutes later be doodoo compression from lean runs from tempo lines,oil filter gunked and from brittle oil lines/cracked OEM painted oil lines.

Neglected oil injection lines are probably the culprit I see take out more motors than anything in excess of ten years of age, I saw ski #9 here today in about a month's time with an original line split right at the end of the injector barb. Those Tempo lines are garbage and absolutely should be replaced but if the carbs are getting any maintenance at all every few seasons they don't do the damage ethanol blended fuel does in two seasons time.

That light aluminum scoring isn't deep enough to affect performance and the liners probably look like new still. It's the deep ones that cause all the issues of heat getting past the rings.

 

[AdamXP800]

The fuel lines are not the issue (independently) we all know this.... It's the adhesive tempo lines and brass reaction with ethanol fuel that causes the goo and kills engines. You can do all the maintenance you want on the carbs but if your running the tempo lines it's Russian roulette on every ride

 

[bier9021]

How do I get a look at my pistons like bonmotwang? Removing the raves?

 

[AdamXP800]

Yes, you can pull them and take a peak. But really no need. You overhauled your fuel system correctly, it's running great and your compression is dead on. But yes you can pull the rave housings and take a peak at your Pistons

 

[bier9021]

Should I clean the raves?

 

[AdamXP800]

Yes that you should definitely do. Text me

 

[Bonmotwang]

Should I clean the raves?

Yes. Not just work better. They look better too!





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[bier9021]

Cool. Curious to see my raves and pistons.


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[Bonmotwang]

How do I get a look at my pistons like bonmotwang? Removing the raves?

I have patented it :-D but it expired the same day

remove the raves and put your iPhone camera at the port, you need a camera app that leaves the flash continuously on.
Take some nice shots and post them here.

In my boat thread I used photoshop to connect all the slides together and recreated the whole image of the piston.


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[Bonmotwang]

Cool. Curious to see my raves and pistons.


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Did you see the "before"? It was nasty.


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[bier9021]

Will do. [MENTION=60330]AdamA96XP[/MENTION] walked me through rebuilding my carbs, fuel lines and everything in between. Great site with great info.


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[bier9021]

I did. Which peaked my curiosity.


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[Bonmotwang]

Just checked the manual. I thought at the bottom of the bellow it was missing a small spring ring, but no it doesn't have one. is the rubber tight enough to stop the exhaust from leaking out? There is some black exhaust leaking marks around the rave area.


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[Bonmotwang]

Will do. [MENTION=60330]AdamA96XP[/MENTION] walked me through rebuilding my carbs, fuel lines and everything in between. Great site with great info.


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Yes. This is a great community here. We should use it and take care of it.


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[AdamXP800]

There is a small spring at the bottom of the bellow which secures the bellows to the housing

 

[AdamXP800]

This is not the one securing the bellows to the piston on top

 

[Bonmotwang]

This is not the one securing the bellows to the piston on top

Thanks. This must be the aftermarket ones. The stock RAVE doesn't have that small ring according to the shop manual.

 

[AdamXP800]

I always use the retention springs. It keeps the bellows on the housing and helps prevent melting the plastic Pistons and rave caps

 

[Waterluvr]

Later models and replacements used that small base retainer, your original bellows didn't have them.