Super Jet Is this what they call pitting?What next

[munki63]

So Ive started getting my ski ready for next year, selling parts, buying parts... So I did a compression test just to do one, 160/130 thats odd I thought there is only 1 season on the top end...Lets take a look
What happened? the other cylinder/dome are mint! and then there is this...there is also a decent "scratch" in the sleeves
What are my options?

 

[Matt_E]

Something in your motor came apart and bounced around. You need to tear that motor down to find the cause.
You also need a bore & new pistons, and new domes.

 

[XJCrawler]

Something in your motor came apart and bounced around. You need to tear that motor down to find the cause.
You also need a bore & new pistons, and new domes.

If something came apart in the bottom end, wouldn't damage both cylinders?

 

[OCD Solutions]

If something came apart in the bottom end, wouldn't damage both cylinders?

The bottom cases are not common between cylinders.

 

[Matt_E]

No. The two sides are pretty well isolated from one another.
If you lose a rod bearing in one side, it won't show up in the other side.

 

[munki63]

No. The two sides are pretty well isolated from one another.
If you lose a rod bearing in one side, it won't show up in the other side.

I never noticed any problems with the ski when the season was over...thats kinda the weird part, last season the ski dieseled on twice??
If it was a bearing wouldnt i notice something..funny? lol

 

[Matt_E]

You could put it back together and pretend you didn't see anything.

 

[munki63]

You could put it back together and pretend you didn't see anything.

I should!! But your best bet is a bearing?

 

[Boris]

How are your reeds ?

 

[munki63]

they were fine, i was running deltas and they slill looked really good

 

[Matt_E]

I should!! But your best bet is a bearing?

Since you say the reeds are fine, it's either bearings, piston pieces, or rings.
You have to tear it down, so you'll find out first-hand.

 

[orangefinger]

Piston ring, pin-clips,spark plug,pin-spacer -washer,rod baring,rode spacer, oem reeds,whatever it was ..... take the engine apart and take your time inspecting it precisly, good clean up after damage is found, and then as matt said, new bore/hone/pistons etc...

 

[munki63]

Or send it to X-metal....get a 771.... this will be the 2nd time this f***ing thing will need to be rebuilt, last time I took it to a local guy

 

[Proformance1]

I always say the disassembly and investigation is the most important start to a new build. If you don't know why it went bad you'll relive the problem again. When I had my shop I didnt even like to touch an engine unless we took it apart. You'll find the issue, just take you time, look at everything involved, well assuming you have done this type of thing before. By the looks of it, I'd have the crank gone through also.

 

[munki63]

Found it...lol how the heck does this happen??
My next worry, what kind of damage would/could this do to the cases/crank?

 

[Matt_E]

Depending on how the bearings feel, I might use the crank as-is in a stock application where I don't care if the motor blows up.
In a pro-ported motor or even an aftermarket cylinder - no way, no how.

 

[munki63]

are you talking about the crank & cases or just the bearings?
edit
just took a closer look at the crank/cases/rods they all look pretty god other then some minor scratches in the case...not sure how big a deal scratches are...

 

[Proformance1]

How many hrs are on the crank. My 05 had about 350 on it, it looked fine but I wasnt sure, so I had Pat pull it apart and one rod and one bearing were going, so good thing I did. If you have alot fo ride time on it, replace it. Its not worth the time and effort to have it go again on you.

 

[munki63]

Ive probably got about the same amount of hours on it as you had, other then just spinning it and feeling for imperfections are there other tricks to checking out if your crank is ok, Ive done lots of wrenching but never touched the cases or crank

 

[#ZERO]

Don't bother with checking it, your lower rod bearings are toasted and SBT cranks are 200 bucks.