brass flakes in oil

[Lars]

some time ago I changed the oil and yesterday I was pouring the oil from a bucket into some empty oil-canisters (so I could dispose of it) when I noticed the bottom of the bucket  had  tiny brass particles sitting on it. There were some bigger particles also from other metals....  the engine sounds and performs still good, it has 50000 km's on it.
Does this indicate bearing failure, and if so.. does anyone know if this could be a particular bearing? I mean: do all the bearings in the GS contain brass, or just a couple of specific bearings??

[The Buddha]

I see that all the time. My theory is that some non metallic crap gets that golden hue when its in oil. Like sand, and other road crap ... and mainly that is sitting in the pan already ... you have a dual layer pan right ... Anyway mine is and its got tons of crap you cant clean out.
Cool.
Srinath.

[JamesG]

All of the GS's bearing are of the plane (plain?) variety.  Unless the clutch side of the main tranny shaft has a ball bearing, but I can't remember off the top of my head. Anyway, small metallic flakes are normally produced in the engine, but noticable "brass" bearing material is a bad sign. There is really no way to know which one(s) it is just by looking at the oil debris. But its probably the crank or the counter balancer, they are the usual suspects.  

50K kms is a a pretty good distance on a GS motor. You are going to have to decide if its worth the expensive and difficulty to tear down and inspect each bearing to find the one going bad than to just ride it until it starts making "bad noises".

Good luck.

[Roadstergal]

OK, it's either nothing, or your engine is falling apart.   :lol:

Brass in a bearing?  Aren't they usually aluminum?

[Lars]

I see that all the time. My theory is that some non metallic crap gets that golden hue when its in oil. Like sand, and other road crap ... and mainly that is sitting in the pan already ... you have a dual layer pan right ... Anyway mine is and its got tons of crap you cant clean out.
Cool.
Srinath.

well, the bucket still had a bit of soda/sand residue in it when I used it to catch the oil from the GS.  I poured it over from the bucket to the canisters in bright sunlight, but it didn't look like sand covered in oil, it was shining very very bright.  

Another thing: the 5th gear is making a sort of grinding sound when you ride at 100km/h, but that never really surprised me because endurance-tests from bike-magazines showed that 5th and 6th gear pitting was a common problem among the GS's with high mileage.

The engine still runs smooth and idles very evenly at a normal pace. Only after 7000/8000 rpm (continuously) it makes a lot of noise. I don't know exactly what it is, but my dad has an old aircooled Honda, and at 8000rpm it doesn't make a lot more noise than at 5000 rpm. My bike sounds like it's going through the soundbarrier constantly, It's literally deafening    It still performs like it should, and I mean it performs like a GS-engine with 50000km's on it, so I don't reach 180km/h anymore.  

I guess now I've gotten close to the point where it's going to give up.
I always did the oilchanges at the recommended intervals or even sooner. It has seen a lot of highway though, mostly at 7000rpm. Even one time 8000rpm or more continuously for 2 hours.


Oh, by the way, I'm talking about a GS500E, 1993 model. The 5th/6th gear stuff may not apply to newer bikes, maybe they fixed that.

[The Buddha]

That 89 I had for 48K never made any extra noise at 7-8K, and it certainly didn't make extra noise in 5th or 6th ... so I dont know what you talking bout ... Its 48K miles not KM. The damn thing used more oil than it did gas though ... quart in 300 or less, but I never let it run out or even low ...
Cool.
Srinath.

[Lars]

That 89 I had for 48K never made any extra noise at 7-8K, and it certainly didn't make extra noise in 5th or 6th ... so I dont know what you talking bout ...

Cool.
Srinath.

It was a test done by a German magazine which tested the bike for 40000 km's. the test was done on an '89 model. After the test they took the bike apart and found the damaged gears. They also found that the valveseats were worn and the cylinder or piston (don't remember which one)  was just out of spec. But overall it was still performing OK.

For the sound: I don't know what it is, but it sounds like everything is a bit worn and has some extra clearance. (I know that's vague to say the least, but that's what it sounds like  to me )

[The Buddha]

OK I dont doubt the piston and cylinder wear ... I have my doubts on the valve seat wear ... cam shaft maybe ... mine always went loose needing thicker shims indicating camshaft wear ... and the fact it used oil pretty much wihtout smoking makes me think its valve seals were toast ... meaning the stem and guide wear will be minimal due to the abundance of oil running down in there due to a worn seal ... and transmission ... I have been told I am very easy on a transmission and clutches even by some people who know my riding style ... so maybe its related to being a bit ham fisted or footed ... and they were worse than me ... In effect you may be right on par with what they said is average ... just that I dont follow that same use pattern.
Cool.
Srinath.

[Blueknyt]

plain bearings are generaly  a lead plated tin,copper,brass.  the tranny uses roller type berings

[Lars]

OK I dont doubt the piston and cylinder wear ... I have my doubts on the valve seat wear ... cam shaft maybe ... mine always went loose needing thicker shims indicating camshaft wear ... and the fact it used oil pretty much wihtout smoking makes me think its valve seals were toast ... meaning the stem and guide wear will be minimal due to the abundance of oil running down in there due to a worn seal ... and transmission ... I have been told I am very easy on a transmission and clutches even by some people who know my riding style ... so maybe its related to being a bit ham fisted or footed ... and they were worse than me ... In effect you may be right on par with what they said is average ... just that I dont follow that same use pattern.
Cool.
Srinath.

an extra complication for German (and Dutch) bikes is that they run with a #120 main jet. That causes lots of extra heat, which makes the valve seats wear faster. the extra heat can really kill it. The test-engine had a rod that had turned blue.   My bike is rejetted with #125 main jet, the rest of the bike is stock.

I'm pretty sure I'm very easy on the transmission also, I always shift carefully and smooth without the use of any force. But it wasn't the gear dogs or selector that wore down during the test, it was the gear itself. the theeth of the gear were very heavily pitted, almost to the point that they could break off.