Other 1100 Went Boom - what caused this - how bad is it?

icecoled007

icecoled007

Captain of this ship
Location
Colorado
Just bought this 1100 of Craigslist - I guess I needed a project and wanted less garage space :)

I have never completely rebuilt a ski before, or had one blow up on me (knock on wood)

Looks like this center cylinder caught the exhaust port and chipped away, the back one as well. Overall there doesnt seem to be much damage (compared to other pictures I have seen on here). The cylinder wall directly about the exhaust is scraped but everywhere else feels smooth. The head look to be in good condition also (no mashed chunks ect). The motor turns over just fine (crank not catching or seized)

What caused this? Low oil? Heat? Does it look repairable? How bad does it look? Should I do a complete tear down and open up the bottom end or just the top end?

Id like to get your opinion











 
Matt_E

Matt_E

steals hub caps from cars
Site Supporter
Location
at peace
A very cost effective way to fix this is to get an SBT topend exchange kit. They send you cylinder, pistons, all gaskets needed.
 
Matt_E

Matt_E

steals hub caps from cars
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If it were me (and it has been me on multiple occasions, but working on customer skis), I would pull the engine out. Remove the topend and pistons. Visually inspect the big end rod bearings. Spin the crank to make sure it is smooth without noise.
If the crank or cases are bad, I'd go with an SBT motor. Well, maybe not if the cases are busted. SBT charges pretty heavily for that.
 
JamesG

JamesG

Site Supporter
Location
Here
Wow that's messed up regarding the piston arrows. I agree with Matt, give us at SBT a call after you inspect it and we will work something out.
 
Matt_E

Matt_E

steals hub caps from cars
Site Supporter
Location
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By the time you figure in your own time and the hassle it can be to find competent machine shops to do your boring, the SBT options are far better values. Been there and done it both ways.
 
icecoled007

icecoled007

Captain of this ship
Location
Colorado
Thanks guys, I havent had any time to mess with it yet this weekend. Was to busy riding my other skis :) - a good problem to have

Once I pull the top end I will report back. Not to sure what I am lookign for in the crank as I havent pulled one apart before. Its a little worrysome that there is fuel/water/oil in the bottom of the hull. Could that indicate cracked or broken cases? The motor seems to turn over find (aside from piston rub)
 
Matt_E

Matt_E

steals hub caps from cars
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at peace
I've seen water/fuel/oil in a lot of sitdown hulls that did not have holes in the cases. Shade-tree mechanics pull off the oil or carb lines and don't block them.
That said, I would pull the entire motor and at a minimum, remove the topend and intake manifold so that you can get a good look at the crank and cases.
 
Matt_E

Matt_E

steals hub caps from cars
Site Supporter
Location
at peace
I've done a few. It's easier to remove the motor if you take the topend off first.

But general order of disassembly (starting in the hull) is this:
  1. Remove flame arrestor assembly
  2. Remove carbs
  3. Remove head pipe
  4. Remove head (looks like that's done)
  5. Remove as much of the exhaust between cylinder and waterbox as you can
  6. Remove cylinder
  7. Remove PTO cover
  8. Remove starter
  9. Remove wiring/hoses/etc from motor (plug oil lines!)
  10. Unbolt motor and take it out. That thing is heavy.

Once you have it out, take off the intake manifold and reeds and check for debris in the reeds and intake tract in the cases. You should also be able to give the crank a good look-over like that. If you have any doubt, take off the flywheel and stator, engine bed plate, and split the cases to remove the crank.
 
iangdesign

iangdesign

Cats, lots of cats!
Location
United States
A cut my rebuilding teeth on an 1100 stx. Ordered all the parts and did it myself. Took it to the lake and it grenaded 30 minutes in. $1300 dollars later I had a huge paperweight sitting in my garage. Go the SBT route.
 
icecoled007

icecoled007

Captain of this ship
Location
Colorado
iangdesign said:
A cut my rebuilding teeth on an 1100 stx. Ordered all the parts and did it myself. Took it to the lake and it grenaded 30 minutes in. $1300 dollars later I had a huge paperweight sitting in my garage. Go the SBT route.
Click to expand...

What caused the grenade? Pistons in backwards? j/k :)
 
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