Second one on my 2011 ZX-10R and this one is a doozy. KHI apparenly screwed up when they machined the cases in the area of the starter mount and the starter boss is cracking in the 90 degree fillet area. Oil can leak onto the rear tire and ......that's all folks! A real confidence builder. The "fix" is the dealer will have to tear your bike down including draining the coolant and removing the throttle bodies to gain access to the repair site. Then they are instructed to punch 10 small dents in the affected area to give "tooth" and apply a structural epoxy. This is a bandaid repair, the real fix is a new set of engine cases with proper wall thickness in the starter mounting boss but that would bankrupt KHI. I wonder what effect this will have on ZX-10R resale values?

This is a bandaid repair,

Sounds like that to me too but you know how these recalls go....my busa has a rectafier recall fixed by being replaced free at auth dealer shop. 3 years now and my rectafier is just fine. Like most, my 14s rod bearings are fine too. i would wait ... see how many 10s are effected. Might be only a few. Doesn't sound like that patrt would recieve a lot of stress. Prolly leak before it lets go.

Hardly enough to bankrupt KHI if all the cases were replaced!

A lot of the guys are bitchin they want a crate motor or a new bike, ain't gonna happen. The problem is not that big a deal, apparently only a small number of bikes had the leak but they're recalling all of them to be on the safe side.

It is caused by porosity in the cases during the casting process, air bubbles became trapped in the molten aluminum and when they machined it with an endmill to accept the starter boss it cuts into the porous metal and you have a leak or crack from the weakened wall thickness.

The fix is structural epoxy since there is no real mechanical load on the area and no real oil pressure behind it.

This is with the starter removed, you can clearly see the discolored area where the porosity exists.

[image assist... -bg]

* Last updated by: bgordon on 8/21/2012 @ 8:45 AM *

If I may... generally speaking porosity is NOT considered deleterious to a materials mechanical properties. This is due to pores forming as spheres and as such, they don't contribute to fracture propagation.

Obviously a mega shit-ton of pores, concentrated in a small area, are going to have some impact on a materials fatigue life. But what I'm seeing in this thread is a minor weeping issue and nothing more.