Cracked engine - leaking oil

[CVSensei]

So I just started the first oil change on my 400 mile MT.

Changed filter no problem.

Drained oil no problem.

Went to tighten up the bolt when I noticed there was a crack about 4cm long running underneath the casing.

I'm sure I didn't over tighten it, I only have a little torque wrench and I hardly gave it any effort which makes me think it might have already been there and I just made it worse.

Spoke to dealer and Yamaha assist about warranty and both of them got very tight lipped when I said I was changing the oil myself.

They're picking it up in the morning to take it to the dealer to check it out - anyone have any advice?

 

[Igor]

Has to be a material failure. No way you could have overtorqued it to crack the sump!

The threads would have stripped before that happened surely?

 

[CVSensei]

I sincerely hope they share your opinion!

 

[Gee]

Why were you changing the oil at 400miles on a new MT?

Was it because the oil level was low or you noticed it was using a lot of oil?.......hence could it have been cracked on delivery/inital setup?

Catch my drift

 

[shadowmonkey]

Was it because the oil level was low or you noticed it was using a lot of oil?.......hence could it have been cracked on delivery/inital setup?

Catch my drift

Like what gee said.

I remember when I took my Ktm 690 smcr to a track day and blew the lower piston ring, never told the dealer though and got a rebuild under warranty.

 

[Noggie]

there is no way you could do that with the oil drain bolt.
There would have to be a weakness in the casting of your engine.
Like Igor said, you would strip the threads or snap the bolt before you would crack the housing.

 

[CVSensei]

Yes yes I like this keep it coming. Can you confirm my suspicions that a sump case should be made of very tough material that I should not be able to crack?

Just so I can speak with confidence when I go to war!

The oil light had actually been coming on when I start the bike but would disappear when I started ignition. Is that normal procedure or is that something I can use?

It was actually one of the reasons I went to change myself because I was getting paranoid. Oil was so dark I couldn't even read the meter as well.

 

[shadowmonkey]

Oil light should come on-on start up and go off when started, as there is no pressure until the engine is running and moving oil around.

 

[Ralph]

Hard to tell off the pic but is the washer still in place? if not I would think about
installing it before the dealer gets his hands on it.

 

[Yaminator]

Where's the crush washer...?

 

[Noggie]

as some has pointed out there should be a brass crush washer between the bolt and the sump.
however even without that washer you would have to put some serious torque on that bolt to crack the sump.
I would suspect there was some defect in the casting, or in the machining of the drain hole.
looking at the crack should give a good indication on why it cracked, also if the crack is old or new.

 

[CVSensei]

Hard to tell off the pic but is the washer still in place? if not I would think about
installing it before the dealer gets his hands on it.

There seemed to be one that was virtually attached to the bolt, I couldn't get it off.

 

[Ralph]

If there's no washer the bolt will go slightly further into the threads and may allow the bolt to
bottom out or maybe try to engage a un-machined part of the bore this could cause the problem
you have hence to suggestion you fit the washer if its not there.

 

[CVSensei]

Well the bike is now at my dealer so I'll have to wait and see what they say. Thanks for your input.

 

[nobull]

I agree with all of above - one other point, did you reuse the original sump plug or fit another yam one(as opposed to omitting it completely)? If it was aftermarket change it to OE and put a crush washer in BEFORE it gets inspected. A marginally oversized bolt could do it but wouldn't be easy to put in in first place, or if you put it in without washer in theory the last, unthreaded bit might be able to split the sump (but still highly unlikely). If you used OE parts & didn't forget washer, threaten to get an independent engineers report in writing to prove metal/manufacturing defect, and demand original parts be returned to this effect, if need be put it in writing. After dealings with Honda and Suzuki UK (both outstanding customer care), I have been appalled at Yamaha's attitude to my dealer problems. Let us know how you get on.
Oops! Just read last post - its already at dealer!

 

[Nuggets]

there is no way you could do that with the oil drain bolt.
There would have to be a weakness in the casting of your engine.
Like Igor said, you would strip the threads or snap the bolt before you would crack the housing.

Steel bolt vs alloy casting? My money is on the steel bolt all day long. The casting will fracture long before the steel bolt failed.

 

[Noggie]

Steel bolt vs alloy casting? My money is on the steel bolt all day long. The casting will fracture long before the steel bolt failed.

that depends on the steel alloy. bolts tend to be soft, as getting out a broken bolt is easier than re-tapping and threading a hole.
I once used an impact wrench on a cars suspension bolt, I ended up twisting the bolt and stretch it until it snapped off, no damage to the casted hole, just removed the old bolt with a a pair of vise-grip pliers and put in a new bolt.

Not saying its not possible, but with normal hand tools I find it hard to believe. had OP used a 3ft extension on a 3/8" ratchet I would agree.
Having worked on car as a hobby for 20 years, 10 years as an aircraft tech, and 9 years building oil rigs I have not seen casted metal crack very often, even when seriously over torqued.

 

[CVSensei]

Update:

Yamaha accepted my warranty claim and a new sump is in the post!! HUZZAHHHH!!!

You guys had me convinced they were dishonorable swines

So fitting the new sump, my Zard Full System and a HID, happy days indeed.

 

[Igor]

Good to hear you're getting it sorted. Doed depend on the dealer sometimes as to who's side they are on.

 

[CVSensei]

You mean from Yamaha's point of view? Like whether they want to help out that dealer?

Because surely the dealer doesn't have the final say on it, purely up to Yamaha right?