Topic: cracks behind oil pump

[artguess70]

I'm rebuilding 1977 CB550 motor and found all these cracks behind the oil pump am I screwed or is this repairable etc

[70CB750]

That's from production.  When you die cast aluminum, it happens sometimes.   It was alaways there, don't worry about it.

[artguess70]

Wow that is great news thank you so much I've been quite depressed thinking it was ruined 😂

[Don R]

 It's scary looking but if it was going to be a problem it would have been one by now. I ran a die cast machine for 6 hours once, making lawn mower engine cases. The QC guy came by and threw away all except two.

[70CB750]

It's scary looking but if it was going to be a problem it would have been one by now. I ran a die cast machine for 6 hours once, making lawn mower engine cases. The QC guy came by and threw away all except two.

My first professional job after college - mech.eng - was preparing manufacturing processes in tool and die factory plus designing tools and electrodes.  I loved that job.  There was a small foundry casting limited series of aluminum pieces - learned a lot from old hands and the whole production.

One motorcycle relevant customer was Yezdi from India - we made new forms and refurbished old ones for engines.

[artguess70]

That's cool and I'm glad to know that it is okay just the way it is so I will continue rebuilding and not worrying about what looks like cracks behind the oil pump

[dave500]

youll notice other fake cracks aswell all over these,they have been posted before as cracks but turn out to be castings flaws or flash.

[artguess70]

Ok thanks for the info!