Author Topic: Mystery Swarf Discovered In Oil Pan (CB750F)  (Read 1209 times)

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jumpjg

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Mystery Swarf Discovered In Oil Pan (CB750F)
« on: May 13, 2009, 08:03:19 AM »
Been working on getting my recently acquired '77 F on the road. Serial number checks indicate the engine has been replaced with one from a '78. I decided to remove the oil pan to check things out and investigate a wet-sumping problem. When I pulled the pan to access the pump, I found a pile of fiber flakes. They are kinda diamond-shaped, dark brown,  aproximately 3/4" long, 1/2" wide , and about .025 - .030" thick. Total number of flakes was around 30-40. At first I thought they were friction material delaminating from the clutch plates, but a subsequent disassembly and inspection of the clutch revealed it wasn't the source. Now I'm wondering if the flakes could have come from the cam chain guide opposite the tensioner (never seen one in the flesh). The flakes seem to be somewhat uniform in shape and thickness, so I suspect they came from something that is made up of many layers or serrated. They kinda look like left-over pieces from a poorly executed cover gasket replacement that were left inside the engine, but too uniform to be that. One last thing - I believe the clutch fiber plates in my clutch are not original. The factory shop manual identifies radial grooves spirialing out from the center, whereas the ones in my bike have square friction pads. Dimpled steel plates are still present. Perhaps there was a previous clutch failure and these flakes were never cleaned out. Any ideas?

Thanks for your time,

Joe in St Louis

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Mystery Swarf Discovered In Oil Pan (CB750F)
« Reply #1 on: May 13, 2009, 09:42:35 AM »
Joe,

We gotta have pictures. Pictures. We like pictures. Otherwise it's just uneducated guessing vs educated guessing.
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline robe0531

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Re: Mystery Swarf Discovered In Oil Pan (CB750F)
« Reply #2 on: May 13, 2009, 09:48:42 AM »
would be able to make a better guess with pics
but could it be a few pieces of clutch plate fibers
1978 cb750k
1968 Honda ca160

Offline IHWillys

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Re: Mystery Swarf Discovered In Oil Pan (CB750F)
« Reply #3 on: May 13, 2009, 10:08:27 AM »
...Perhaps there was a previous clutch failure and these flakes were never cleaned out....

This is where my money would lie, given the evidence.

However, I'm not a bettin' man because I don't like losing money for nothing...and I don't know the internals of these engines like many others here do.

Oh, and I first read this thread's title as "Mystery Dwarf..." hehe.

Ken
« Last Edit: May 13, 2009, 10:09:59 AM by IHWillys »

Offline Chester345

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Re: Mystery Swarf Discovered In Oil Pan (CB750F)
« Reply #4 on: May 13, 2009, 10:23:11 AM »

My first take on the title was Mystery Scarf...and I clicked it really fast because I just had to see that...

Offline mystic_1

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Re: Mystery Swarf Discovered In Oil Pan (CB750F)
« Reply #5 on: May 13, 2009, 10:29:04 AM »
Could be material from the cam chain tensioner rollers.  Not uncommon in high-mile 750's that weren't adjusted often enough.  Chain slaps the rollers and starts tearing out semi-uniform chunks.

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jumpjg

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Re: Mystery Swarf Discovered In Oil Pan (CB750F)
« Reply #6 on: May 13, 2009, 10:57:56 AM »
Sorry, not digital pic enabled, but my neighbor's boy is. I'll see what I can do tonight.

 I wouldn't suspect the chain tensioner rollers since the flakes are flat and thin. Are the guides made from a laminated material or solid?

Thanks for the help,

Joe in St Louis

Offline hapakev

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Re: Mystery Swarf Discovered In Oil Pan (CB750F)
« Reply #7 on: May 13, 2009, 05:24:09 PM »
The first clutch plate should be spiralled and the rest are square chunks.  Could it be your oil filter?
Smoking Jack
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jumpjg

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Re: Mystery Swarf Discovered In Oil Pan (CB750F)
« Reply #8 on: May 14, 2009, 08:56:28 AM »
Upon closer inspection last night, I've concluded that the flakes came from an earlier installed (failed) clutch plate. They look to have a cork texture, and some flakes showed the undercutting that form the slots between the friction pads. I guess it has been a while since the oil pan has been removed :o

Anybody else ever seen this?

Thanks for your time,

Joe in St Louis

Offline robe0531

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Re: Mystery Swarf Discovered In Oil Pan (CB750F)
« Reply #9 on: May 14, 2009, 07:21:46 PM »
i seen it on a busa after a few hard 1/4 mile runs but not in my cb750
1978 cb750k
1968 Honda ca160

Offline Scrubs

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Re: Mystery Swarf Discovered In Oil Pan (CB750F)
« Reply #10 on: May 14, 2009, 07:25:13 PM »

My first take on the title was Mystery Scarf...and I clicked it really fast because I just had to see that...

Better than me - I thought it was mystery dwarf  :o
Time for bed.