As some know I have removed the engine from the FZ1 to investigate the lower crankcase trying to diagnose my engine noises. I have found the the bottom rod cap and bolts, as well as the surrounding area od the number 3 piston rod is a burnt black color. The other 3 are a normal clean appearance. To any who are familiar with rod bearing issues does this sound like a blown rod bearing?
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Current Bikes:
2001 Yamaha FZ1 (bought same one back) -
20201005_182446(1).jpg
The burnt one.Current Bikes:
2001 Yamaha FZ1 (bought same one back) -
20201005_182456(1).jpg
The other 3 look like this.Current Bikes:
2001 Yamaha FZ1 (bought same one back)Comment
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The huge majority of failures like that trace to oil starvation. There is a very good chance that the crank is scored on that journal. Hopefully you can find some good, but cheap, parts to fix it up.Ed
To measure is to know.
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Those motors are readily available in pieces or as whole units. Great lumps, those.
"Thought he, it is a wicked world in all meridians; I'll die a pagan."
~Herman Melville
2016 1200 Superlow
1982 CB900fComment
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My first question - are there any metal particles on the oil pump pickup screen ?
If so, then yes, you've done a rod bearing for sure. Until you split the crank you don't know what you're dealing with.
I've done several of this family of engines - FZR1000 based range. The early ones had a well known problem of stretching the rod small ends but later rods don't do this.
None of them have what I'd call well finished cranks. When you do split the crank, look at the edges of the oil holes at the crank surface. Frequently they've been left sharp.
This sharp edge peels the oil film off the bearing leading to early failure.
If you buy a used crank, I'd prep it properly, radius the oil hole edges and get it linished by an engine shop.
Rod bolts can be reused - they're not torqued to yeild point. If the shells look good, reuse them too.Comment
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Thank you. My problem originated when I installed the cam chain tensioner incorrectly, not realizing they do not retract under spring load, so it was waaaaay too tight. It ended up causing the cam chain to grind away at the intake side chain guide leaving ground up black plastic all over everywhere around the top of the chain opening at the top of the head. I cleaned it all out, then took off the oil pan and found it all in there too, as well as clogged up the pickup screen. I cleaned it all out there too, but I suspect it got into the oil ports supplying the rod bearings and blocked that one out. I did find several crank shafts for sale on ebay in case I need to get another. I'm currently waiting a some tools to be able to remove the alternator rotor so I can split the crankcase and get to it.Current Bikes:
2001 Yamaha FZ1 (bought same one back)Comment
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I chose it because it was one of the (purportedly) nicer examples."Thought he, it is a wicked world in all meridians; I'll die a pagan."
~Herman Melville
2016 1200 Superlow
1982 CB900fComment
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I think I may need another crank. Looks scored.
20201011_154007(1)(1).jpgCurrent Bikes:
2001 Yamaha FZ1 (bought same one back)Comment
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That thing really got hot. Before pulling the cap off, I could grab it and rattle it back and forth, hense my mysterious engine rattle. One half of the bearing was rotated halfway overlapping the other half.
20201011_155528(1).jpgLast edited by ddaniels; 10-11-2020, 04:45 PM.Current Bikes:
2001 Yamaha FZ1 (bought same one back)Comment
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Ouch!!!!!!"Thought he, it is a wicked world in all meridians; I'll die a pagan."
~Herman Melville
2016 1200 Superlow
1982 CB900fComment
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