[KurtD]

I just drained my oil and noticed metal flecks in the oil. Is this normal? It has been under 1000 miles since the last oil change and I change filters every other oil change. Could the shiny flecks be from the clutch? Took the bike out for 170 miles last weekend and everything worked great. Here is a picture of the tail end of the oil. The first part of the oil had more flecks.

Thanks

 

[KurtD]

A little more information on the bike. The engine has 8400 miles on it. At least that is what the odometer says and it has worked for as long as I have owned the bike. It is all original as far as I can tell.

 

[80cb400t]

Can you give more detail on the flakes? Are they copper, are they aluminum, are they magnetic/steel? Does your oil smell like gas too? Has it ever been run low on oil?

 

[KurtD]

I would say the oil smells a little like gas and the flecks look more like copper than aluminum. The oil is mixed with other oil at this point, but I could remove the oil filter cover ans see what is in there.

 

[KurtD]

Tho oil filter cover was clean. No deposits of metal sludge. I ran a magnet through the oil in the cover and in the filter and nothing stuck to the magnet. Here is a picture of the filter cover.

 

[KurtD]

The previous picture didn’t load.

 

[80cb400t]

That's odd because copper usually means rod bearing/main bearing damage, but that is unusual unless you spin one from running low on oil, and you'd probably be getting loud knocking the whole time the engine runs. I'm not sure what else it would be, maybe a copper washer or something somehow got into the engine during a valve adjustment?
If the oil smells a little like gas I would definitely make sure your petcock isn't leaking in the off position.

 

[KurtD]

I will check the petcock to make sure it isn’t leaking. Thanks

 

[KurtD]

I checked the petcock and it does not leak when in the fully off position. However, if it isn’t lined up just right, it does leak.

I changed the oil and started it up and there is a ticking noise on the left side. The noise is loudest between the cylinder and the head. (I listened through a plastic tube to try and pinpoint the noise.).

If gas was leaking into the cylinder while sitting, could it cause wear and result in the ticking noise? I realize it is going to be tough to answer that question without being able to hear the noise. I may have to bring it to someone with more experience with these bikes.

 

[80cb400t]

It's only really a problem if the oil smells like gas, then it gets thin and doesn't lubricate properly and it's usually the camshaft that suffers although that seems to have happened more to the late 60s early 70s bikes.

If you have a friendly shop nearby you could ask them to listen to it and it probably won't cost you much if at all.

 

[longdistancerider]

A little unusual for these engines. I'd suggest popping the valve cover off and using a syringe to drain the oil bath reservoirs under the cam. They're big pockets that hold oil the cam runs thru to lube it. They never drain unless the bike is laid on it's side, it's not usually an issue since with good clean oil and regular changes they self flush but with an engine that's been barely run the particles in the oil will separate and sink to the bottom and collect there. Refill them when done and run the engine until hot. Drain the engine, refill, run, drain again. After a couple of oil changes I'd thing the issue will resolve itself. No need to change the filter each time while doing this but the filter should be changed out every regular oil change.

 

[KurtD]

Jim, thanks for the information above. Unfortunately, I had swapped out the motor with a spare so I could keep riding and not cause anymore wear.

I finally got around to doing a little work today and did a bench compression test. With some jumper cables I used the starter and the test came out L-150 R-155. Added the same amount of oil to each side and it tested L-155 R-168. I believe that is pretty good for being tested cold. I’m not sure if the difference between the two measurements on the right side means something is wrong with the rings.

After the compression test I started to remove the cylinder head. I had heard that foamy oil in an air cooled motor could be from exhaust gas getting into the oil due to a blown head gasket. But the decent compression has me thinking that the head gasket isn’t leaking. 7 of the head bolts came out nicely, but one of the interior bolts was very difficult. It came out, but some of the threads were messed up. The oil in the baths looked pretty clean except for a couple small ones on the outside.

I’m hoping the threads in the block aren’t messed up where the one bad bolt came out.

 

[KurtD]

I removed the camshaft to see if there was any obvious wear. There is some scoring, but I am not sure if it is supposed to like that to allow a path for the oil to lubricate everything. I’m going to need to go get a micrometer so I can measure for wear.

 

[longdistancerider]

The cam and journals should be nice and smooth, your's are scored however they may still be serviceable. If your fingernail catches they are bad

 

[KurtD]

I could feel the scratches with my fingernail, but just a little. I got some plastigage and measured the clearance per the service manual. It measured closest to the .076 indicator in the picture below, so I should have a little room to refinish the camshaft journals and the cylinder head/camshaft holders. I may need to try measuring again with a thicker plastigage to get a more accurate reading. The camshaft does not have any noticeable play with the holders in place and spins freely. Since the cam and head don’t seem to be too worn, I am going to keep tearing apart looking for cause of metal flecks in oil.

 

[KurtD]

I managed to repair the threads on the one bolt with a thread restorer borrowed from the local parts store. Looks pretty good and went into its e nicely.

I measured the clearance with a thicker plastigage and it measured a little less than 0.1 mm. Since the service limit is 0.2 mm on the outside and 0.23 mm on the inside, looks like I have a little room to smooth the surfaces.

 

[longdistancerider]

Looks like you're going to be good.

 

[KurtD]

I removed the cylinder head today and was surprised to see so much oil on the head gasket. Is this normal? Also, there is oil in the front outside bolt holes(see picture). I understand the oil in the back outside bolt holes since that is where the oil gets pumped up to the cam, but not sure if oil should be in the front holes. The front holes smell of gas too? Is it possible that unburnt gas is leaking past the head gasket and miking with oil?

The cylinders appear to be in pretty good shape. You can still see the cross hatching. Just a few areas where you can see any vertical wear.

While I have it apart, is it always a good idea to work out on the valves, or if decent cold compression leave them alone?

I am new to this, so if you see any areas of concern in the pictures, please let me know. Thanks

 

[KurtD]

The pictures above didn’t really show the amount of oil on the head gasket. Here is another.

 

[doctorruckus]

Judging by the valves and cylinders, you to have those valves cleaned and potentially lapped in. I don't know this model, do they have valve seals? Your hone job looks like it was done by a methhead with a wirebrush. Looks like you have some oval wear in the cylinders too so you should measure that with some snap gauges to check. Cam looks fine, but you can send it off to Delta cam for around $80 with rockers and have them resurfaced and spec'd.

Edit: that is a lot of oil on the gasket and not normal at all. My guess is the PO didn't clean the surfaces or rebuilt it without replacing the old gaskets.