79 XS1100 Standard Questions

[blue giant]

Re: " Despite the blown motor "

Originally posted by fredintoon
Hi Paul,
so how "blown" is the motor?
One assumes it don't run but is there just a nasty noise when you crank it or is there a big hole in the crankcase with a broken connecting rod poking out of it?
And don't worry about mix'n'match parts because Yamaparts swap like Lego so don't think of your new machine as a dog's breakfast, it's unique is all.

Hi Fred,

Big ugly hole in the lower case with a pretty smashed up con rod sticking out!
I'm going to do a restore on this one and already have a line on two partial engines. (both with good lower ends)

79XS11F is going to give me a hand, although he doesn't know that yet.

[79XS11F]

First thing to do is discover why it let go like that? Is the top end over bored?, Have the cases been split in the past to do other work. Was it run without oil flowing in it? There has to be a reason why it let go like that? After you check it out closely you may discover that the top end is TOAST as well? Start by pulling the engine and doing some investigation of the condition of the rest of the engine. You may find that a complete undamaged engine is the way to go. Cost may not be much different then a partial engine.
Rob

[blue giant]

Originally posted by 79XS11F
First thing to do is discover why it let go like that? Is the top end over bored?, Have the cases been split in the past to do other work. Was it run without oil flowing in it? There has to be a reason why it let go like that? After you check it out closely you may discover that the top end is TOAST as well? Start by pulling the engine and doing some investigation of the condition of the rest of the engine. You may find that a complete undamaged engine is the way to go. Cost may not be much different then a partial engine.
Rob

Hey Rob,

Engine is out, and I'm leaning on a complete engine. I'd like to get together and ask for more of your experienced advice.

I drained a liter of oil and water out of the beast. Think I found the cause of the failure.

Cheers,
Paul

[79XS11F]

Pop out those cams and check out things in the top end
Rob

[blue giant]

Originally posted by 79XS11F
Pop out those cams and check out things in the top end
Rob

Should I be looking for anything specific?

[79XS11F]

Once the cams are out you can check the head parts for gouging, scoring and heat damage if it was run with not enough oil in it. There are no bearing inserts in the head so you have steel cams running on alloy bores. You can also write down you pad numbers for future use if the head is good and gets reused
Rob

[blue giant]

Originally posted by 79XS11F
Once the cams are out you can check the head parts for gouging, scoring and heat damage if it was run with not enough oil in it. There are no bearing inserts in the head so you have steel cams running on alloy bores. You can also write down you pad numbers for future use if the head is good and gets reused
Rob

Thanks Rob!

[blue giant]

Well now........

#1 piston conecting rod is broken away from the crank shaft and smashed a hole in the lower cases. It has also destroyed the piston and cylinder wall. #4 cylinder is scored. I also pulled out from the bottom of cylinder #1 what appears to be the remnants of a crankshaft bearing and block. Not sure what caused the failure, there was plenty of oil on the camshafts and no signs of overheating. Maybe this one was long overdue for an oil change. I have only removed the head and not the jugs. Lots of aluminium filings in the bottom end.

Damn!

Rob- I'll send you some pictures from work tomorrow.

[79XS11F]

Sounds pretty ugly Paul. But the clutch, head and its components and other parts will be salvageable.
Rob

[blue giant]

Originally posted by 79XS11F
Sounds pretty ugly Paul. But the clutch, head and its components and other parts will be salvageable.
Rob

The rest looks good.

I think

[blue giant]

Pictures

Here is a link to pics of my blown engine,

Blown Engine


Paul