brass in oil!

[ryno1100]

I want to start off saying that I've been reading from this forum for around 4 years now and you have all been alot of help for me and my 79 special. Recently my bike died on a 3 hour road trip, so when I got home I started to troubleshoot the problem. Battery, carbs, ignition, wires, coils, and couldn't find anything wrong untill I checked the oil, loaded with brass shavings! Does anyone know what the cause of this could be? It's a 79 xs1100sf with a big bore kit, accell coils and wires, and 4 into 2 exhaust. I just rebuilt the carbs and sync-d them. Oh yeah it has 23,000 miles on it. Thanks guys.

[DiverRay]

Did you replace the cam chain? how often did you check the adjustment?
Did it start to shift hard? There could be a LOT of things, I would start with the "easy to check" and remove the valve cover.

[ryno1100]

The cam chain was replaced about 10,000 miles ago and was just adjusted, the shifting was normal also. I was just crusing along when the bike started to lug down and then it died. No cranking over just dead in the road. The valve cover is coming off tomorrow as soon as I get to the shop, any ideas if I can't find anything wrong there? Thanks DiverRay.

[somesuch]

There is only one place a copper colored flakes would come from and that is from the plain bearings such as used in the mains and in the connecting rod big ends on this motor.... I think you spun a bearing.

If you stop riding early enough you could polish the journals on the crank and just replace the shells. Take a square leather string as used in baseball gloves and wrap it turn-to turn over 400 grit sand paper wraped over the journal, wet it, and pull on the ends. You will see how the string will move and put pressure over the whole area of the journal and polish it very evenly. I know it sounds Mikey Mouse, but it works very good. The GSXR motor that spun a bearing I did this way and it lasted two race seasons.

--Nick

[prometheus578]

"Sorry to say that I have to agree..."

The only "brass-colored" stuff would be bearing material.
There 's other things of a similair color, but they wouldn't stop and lock up an engine.
Looks like a tear-down is in order.
But before you go hog-wild, pull all the covers, valve cover, clutch cover, etc and see what it looks like in there.

[mro]

Oh yeah it has 23,000 miles on it.

Low miles...why the big bore kit?
====

Did bike over heat on the ride or run low on oil?
XSive twisting right wrist while riding?
Who rebuilt the engine?
Did they check bearing tolerances?

Most of the time when a bearing goes bad theres some warning. Varies from few seconds or can run for hundreds of miles making a rather distintive knock, sometimes a screech.


mro