Cracked crank case

[Simon]

After the final race of 2012 in Redding, I noticed an oil leak on my good motor. I assumed it was a side cover gasket sucked in and thought "I'll fix that before the first race of 2013". At the weekend I pulled the sidecover off and found the cause of the leak. A crack in the crank case.



What is also interesting is that the bottom surface of the motor is no longer perfectly flat. If you sit it on a motor mount plate, you can rock the thing slightly across the diagonal.

I assume this crankcase is toast and I need to replace it. I'm also thinking 90% of the good work that was done when it was blueprinted is now for nothing when I move all the components to a new crankcase.

[Dan Pell]

Ouch! A flexible motor mount just might be the contributing factor? It's no secret these things flex, so a rigid mount will help to diminish the potential under throttle. Never have seen a crack there, so a collision with the floor first came to mind until you shared the uneven base. As for blueprinting, the same crank & cam will not equate to identical cam & ignition timing because the side covers are cast at a different time than the block.

[ron90]

Mar 5, 2013 15:40:38 GMT -5 Dan Pell said:

Ouch! A flexible motor mount just might be the contributing factor? It's no secret these things flex, so a rigid mount will help to diminish the potential under throttle.

For the 2013 season I bought two rigid mounts for my two engines. They are supposed to reduce the flex.

www.cometkartsales.com/store/briggs/images/animalpics/an-guard.jpg

They are made specifically for the Animal so modifications are required for the mounting plate, and the starter placement. Nothing a good grinder and 5lb sledge couldn't fix.

[Brad Wunder]

Ah man, that totally sucks. All due to the MM?

[ron90]

I remember when I cracked my head . I don't know what is worse cracking my head, or my bottom. ;D

[brad42]

There is also a stiffening system built in to a chainguard.

www.fastermotors.net/Chainguard.html