Crank damage....how bad is this??? HELP!

shawn_NJ

Chasing waves.
Location
Daytona Beach
Pulled my motor out because I am changing the head. I pulled the reeds out to check them, and I noticed this on the rear cylinder(see below)!! Not sure what went through the motor (I overheated this motor bad once) maybe piston/ring parts???? The cylinder compression is good 165/165. The motor has long since vibrated every bolt on it loose, even if I use red locktite! The piston looks ok, should I run it or swap the crank out?

crank1.JPG

crank2.JPG

crank3.JPG
 
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Hmmm... You seeing any scraps from damage on the reed cages or head domes?? Are you the Orig. owner of the ski?? Has it ever been rebuilt by you?? Just wondering cause maybe the damage was done before you bought the ski, then reassembled with that crank??
 

shawn_NJ

Chasing waves.
Location
Daytona Beach
Hmmm... You seeing any scraps from damage on the reed cages etc.?? Are you the Orig. owner of the ski?? Has it ever been rebuilt by you?? Just wondering cause maybe the damage was done before you bought the ski, then reassembled with that crank??

I bought the motor this spring, and then a week later sent it out to be torn down/rebuilt. It was done by a well known pwc shop, so I have faith that it was not there when it was assembled. The reed cages look fine, no scratches at all. The motor still ran fine, it was soft down low but the motor was run almost nonstop in daytona.
 

shawn_NJ

Chasing waves.
Location
Daytona Beach
Did you look at the head yet?? Sounds like you should pull her apart and investigate, there may be more damage or could lead to more?? Bummer

Ya the head looks fine. Not quite sure how. I am probably going to swap the crank and pistons just to make sure its ready for the summer season.
 

WFO Speedracer

A lifetime ban is like a lifetime warranty !
Location
Alabama
Man there is no way that damage was not there when the engine was reassembled,if it happened later the head,pistons,reeds or something would also have damage to them.
 

shawn_NJ

Chasing waves.
Location
Daytona Beach
The rear piston does have a few VERY tiny indentations from something passing trough, the head looks ok with just a few very tiny indentations.
 
The piston and head are both aluminum. It don't take much to make "tiny" indentations in that soft metal. But that crank web looks like it was hammered with...... well a hammer.
 

Boris

The Good Old Days
If it was mine I would have the cases split by now.

Check all the bearings and locator pins on that thing and also take a good long look at the cases.
You mentioned that the motor vibrates quite badly, maybe it's a sign of a big boom event coming up.
 
Man there is no way that damage was not there when the engine was reassembled,if it happened later the head,pistons,reeds or something would also have damage to them.

agreed. if everything is tight between the carb and cases, and theres no damage in the bore (and your cases arent cracked), id say the damaged was already there and the reputable builder said "fuggit, its fine" (as i wouldve if thats all the damage there was... which isnt much).
 

shawn_NJ

Chasing waves.
Location
Daytona Beach
Pulled the cases apart. Top case definetly shows that something got into the motor. It has a few gouge marks. I am surprised its not worse. Checked all the bearings and everything seemed ok... Well the piston did get a little worked so I am going to throw a new set in, and I dont want to rerun this sketchy crank, so will be putting a new hot rod crank in as well.... I was pulling the motor out to remove the stock head and install an ADA girdled head, so no big deal there. This sucks, but I guess it could be alot worse.
 
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