1991 DT100 Crankcase Puncture

[Sworkl]

Hey team,

I have a 1991 DT100. Took it out on the water first time in a while. Started her up and would cut out while in idle. She’ll run in neutral with a bit of throttle but as soon as theres no extra gas she’ll just cut out.
Pulled her out the water and when I did a bit of digging around I found a hole in the crankcase and it looks like something pierced it from the inside out, or its had a blow out.
Any ideas what could cause this?
Or even where to start!

 

[99yam40]

compression test would tell of all pistons and rings are still intact and moving the way they should.

or just take it apart to see what happened.

 

[racerone]

Motor has to come apart.------Looks like a skirt broke off a piston.-----Or connecting rod broke.-----No point trying to run this motor.

 

[Chris1956]

Look in the lower cowl for bearings, pieces of rod etc.

Does the flywheel rotate 360*?

 

[brodmann]

;If you ran it a long time while it was starving for gas, that could have caused the problem. But if it has oil injection, that cylinder should have gotten oil even if it wasn't getting fuel. If a carb is clogged and there's no oil injection, the cylinder won't get fuel/oil mixture, so it runs dry and causes incredible heat/friction very quickly! I'd do a compression test. If a cylinder has little/no compression, I'd then remove the cylinder heads to see if cylinder is gouged. You may be in the market for a new motor.