Author Topic: Warped crankshaft case? Blown gasket?  (Read 1712 times)

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Offline jaasonkirk

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Warped crankshaft case? Blown gasket?
« on: October 04, 2018, 09:04:29 PM »
After several months of slowing working on my bike I got it running for the first time. After riding around for a bit I noticed it was smoking quite a bit. My first thought was jus all the nasty road grime and oil was burning off. But when I stared closely examined the engine block, it looks like on the left side, thereís a gap between what I believe is the camshaft case and the cylinder head. On the right side, it looks seated with a gasket. Forgive me if Iím not articulating that correctly, Iím very new to working on bikes.

Offline dailydose1

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Re: Warped crankshaft case? Blown gasket?
« Reply #1 on: October 04, 2018, 10:03:28 PM »
Did you re-torque your head bolts?

Offline jaasonkirk

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Re: Warped crankshaft case? Blown gasket?
« Reply #2 on: October 04, 2018, 11:11:58 PM »
No, but I guess that would be a good place to start though!

Offline dailydose1

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Re: Warped crankshaft case? Blown gasket?
« Reply #3 on: October 05, 2018, 02:06:38 AM »
Yes, do it and report back. I'd do a bolt check all around too and tighten them all to spec

Offline jaasonkirk

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Re: Warped crankshaft case? Blown gasket?
« Reply #4 on: October 05, 2018, 08:38:44 PM »
Will I need to remove the cams to tighten the head bolts?

Offline dailydose1

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Re: Warped crankshaft case? Blown gasket?
« Reply #5 on: October 05, 2018, 09:51:18 PM »
No I'm talking about the big bolts on the engine. I dont think you need to even take a single cover off of the engine. Atleast I dont on my 78 xs500.

Offline dailydose1

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Re: Warped crankshaft case? Blown gasket?
« Reply #6 on: October 05, 2018, 09:51:52 PM »
Look on the top of the engine and there are 8 big bolts to torque down. I think they are Allen keys on early engines and bolts on later engines

Offline dailydose1

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Re: Warped crankshaft case? Blown gasket?
« Reply #7 on: October 08, 2018, 12:14:46 AM »
So what's the verdict?

Offline jaasonkirk

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Re: Warped crankshaft case? Blown gasket?
« Reply #8 on: October 08, 2018, 09:24:06 PM »
From what I can tell, to get to the head bolts on my 74 tx500 I need to remove the camshaft case cover and I havenít had the chance to do that yet. But upon some closer inspection, it looks like Iíve got a bolt missing on that left side that seems like it would be holding the camshaft case to the cylinder head.

Offline jaasonkirk

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Re: Warped crankshaft case? Blown gasket?
« Reply #9 on: October 08, 2018, 09:26:00 PM »
Here is what that missing bolt looks like.

Offline dailydose1

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Re: Warped crankshaft case? Blown gasket?
« Reply #10 on: October 09, 2018, 05:12:14 PM »
Yes indeed u do have a missing bolt, and I think there should be two allen bolts that you can tighten down to make that side tighter on the outside of the engine halfway down on intake and exhaust sides on the right of the engine

Offline jaasonkirk

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Re: Warped crankshaft case? Blown gasket?
« Reply #11 on: October 10, 2018, 12:52:08 AM »
Any idea where I might find a replacement for the missing bolt?

Offline dailydose1

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Re: Warped crankshaft case? Blown gasket?
« Reply #12 on: October 10, 2018, 01:06:17 AM »
I'll be working on my bike Thursday or Friday and can let you know bolt size and pitch

Offline jaasonkirk

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Re: Warped crankshaft case? Blown gasket?
« Reply #13 on: October 10, 2018, 05:27:18 PM »
Thanks!

Offline guylr

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Re: Warped crankshaft case? Blown gasket?
« Reply #14 on: October 10, 2018, 10:10:13 PM »
The bolt is a hex socket 8 x 50mm and is part number 91317-08050-00. Babbits says it's still available from Yamaha.

https://www.babbittsonline.com/oemparts/p/yamaha/91317-08050-00/bolt

Here's the page it's on.

https://www.babbittsonline.com/oemparts/a/yam/504f8f1cf870023338d0dcf5/cylinder-head-cylinder

You guys need to use the available online parts sellers like Babbits. The catalog drawings are helpful and they sometimes have the parts you need.

Guy
Now Retired Yamaha guy. Cut me and I bleed "Cinquasia Red"