Author Topic: metal shavings in filter  (Read 192 times)

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Offline Randy Nevrotski

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metal shavings in filter
« on: November 13, 2019, 11:20:37 am »
changed oil on my 1976 CB750A with 6750 miles on bike. dirty and had a light silver tint on top of oil. took filter off. it had shinny little pieces of metal in filter. the filter cup had parts missing , flaking off. I sanded down the whole thing. ran bike still had more in new filter. drop the oil pan and its clean. no metal . Then I took left side of motor apart . alt. was clean. took oil pump out then apart. it was in backwards on one side ,motor oil pump. no marks on pump or shaft. 2nd oil pump for trans was also perfect. I put oil pump back together . with all dots right way. drove around then checked filter. just a little bit in filter.                                             what I understand oil go's from pan to pump from pump to filter. am I right about that? I don't know what to check next. when running plenty of oil to rockers. I took cap off            now what should I do

Offline Don R

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Re: metal shavings in filter
« Reply #1 on: November 13, 2019, 12:31:27 pm »
 If the rockers are oiled and everything appears in order you might just continue to use it. I've had large amounts silver in my race engines filters and three competent engine builders assure me it's normal. However, like you I'm more pleased to see nothing in the filter.
 I would check the cam chain tension to be sure the chain isn't wearing against the cylinder. I've seen a DOHC Honda wear through the cylinder, not a SOHC though.
If the things you own end up owning you, it's better to be owned by some cool things.

Offline Randy Nevrotski

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Re: metal shavings in filter
« Reply #2 on: November 13, 2019, 10:28:45 pm »
but oil pan is clean. anything past the filter will travel throughout the motor . all debris will end up back in the oil pan. that I can figure out if there is a problem its only between oil pick up an oil filter. that I can tell its only the motor side oil pump. .  hondamadic has 2x oil pumps

Offline Don R

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Re: metal shavings in filter
« Reply #3 on: November 14, 2019, 08:23:47 am »
 I'm not aware of the trans oil path but my guess would be it's trans related. Hopefully you will be able to find and fix. Sorry I'm not more help.
If the things you own end up owning you, it's better to be owned by some cool things.

Offline raymond10078

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Re: metal shavings in filter
« Reply #4 on: November 14, 2019, 11:01:01 am »
As you know, there are two pumps; one for the engine, and one for the transmission. 

The filter is place between the engine oil pump and the engine (most of it anyway).  The trans does not receive filtered oil; and the mainshaft and countershaft don't either.

Obviously, the engine oil pump pulls oil from the common sump, so oil in the filter could be from any engine/trans component.  There's not much between the pickup and pump. 

« Last Edit: November 14, 2019, 11:12:52 am by raymond10078 »
1978 CB750A (upgrading very, very slowly)

Past bikes - Honda: SL350, CX650C, CB900C, CB1000C, CM450A; Kawasaki: several 1972 750 H2's; Suzuki: TC90J.

Bikes I want: CX650ED, a mid-sized japanese V-twin with ABS.

Offline Randy Nevrotski

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Re: metal shavings in filter
« Reply #5 on: November 14, 2019, 02:12:54 pm »
thanks that's the answer I'm looking for . if I have a problem then its the motor side oil pump. I couldn't find any diagram showing oil path in detail. I'm in Philadelphia it got cold quick. my bike is parked for the winter. I will worry about it in march just in case I have to replace anything then I will have an early start

Offline vik351

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Re: metal shavings in filter
« Reply #6 on: November 14, 2019, 04:21:32 pm »
Drop the sump and see how much crap is in the corners, then ya would think it's more trans related...???

Yet to drop my sump, had to ride it for a bit first...

next job...

vik...

Offline scottly

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Re: metal shavings in filter
« Reply #7 on: November 14, 2019, 06:36:49 pm »
took oil pump out then apart. it was in backwards on one side ,motor oil pump. no marks on pump or shaft.
Are you sure the metal didn't come from having it in backwards??
Don't fix it if it ain't broke!
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Offline Randy Nevrotski

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Re: metal shavings in filter
« Reply #8 on: November 14, 2019, 11:37:45 pm »
Trying to out pic of OIL pump

Offline raymond10078

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Re: metal shavings in filter
« Reply #9 on: November 15, 2019, 08:06:38 am »
I couldn't find any diagram showing oil path in detail.

I scoured the service manual yesterday, and put the (mental) pieces together.  Section 2 of the manual helped - the pic on page 2-8 helped the most.

« Last Edit: November 15, 2019, 08:08:19 am by raymond10078 »
1978 CB750A (upgrading very, very slowly)

Past bikes - Honda: SL350, CX650C, CB900C, CB1000C, CM450A; Kawasaki: several 1972 750 H2's; Suzuki: TC90J.

Bikes I want: CX650ED, a mid-sized japanese V-twin with ABS.

 

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