Metal pieces

[RICHO2006]

Hello all,


While at the rally in Johnson City, I changed the oil in a '77 r100/7. When the oil was poured out of the drain pan I noticed several small pieces of metal. I was not the first person to use that drain pan so the metal may have been in there already. The pieces measured about 3/16” long by 1/8" wide by about a 32nd thick. The front of the pieces was polished like you might see when looking at a lifter where the cam pushes against it. The back looked like it had broken away from a casting. A subsequent oil change revealed no metal. However, I would like to examine the surface of the lifters and cam. My question is, what is the easiest way to inspect those parts?


Thanks for your help

Richard

[20774]

The whole top end will have to come off. Those pushrod tubes lead to the lifters. They have to be extracted from the bores which then allows you to see inside at the faces of the cam lobe.

How many miles on the bike? What's the status of the pushrod tube seals? Is it possible for a top end update to unleaded valves/seats? You're going to do virtually 100% of the disassembly...all that's needed is to send the heads off for rework. See past threads.

If it were me, I'd strongly suggest buying the top end manual from Oak Okleshen. It'll walk you through this process step by step. $25 from askoak at aol dot com.

[GeorgeRyals]

I believe you can drain the oil and drop the pan to get a view of the cam lobes and lifters. At least a good enough view to see if a piece of metal that size is missing. A bright light and mechanic's mirror may be helpfull.

[20774]

I hadn't thought about dropping the oil pan. I was probably thinking about the /2 where the cam is above the crankshaft, so you probably can't see anything. A post in the Airheads archive suggests doing as George states but that you might not be able to see everything. Certainly, that's a much easier place to start. If you can see enough to convince yourself that the cam lobes look fine, you might be OK. Most likely, though you won't be able to see the complete ends of the lifters as they'll be riding around on the lobes. Spinning the engine would let you see the lobes as they move in the light of your flashlight.

[RICHO2006]

Hello all,

Mileage on the bike is probably 80 k miles. The exhaust valves are starting to recede and I do need to have the valves and seats replaced. I would like to wait until winter to do the valve job. Dropping the oil pan should be fairly easy and allow me to examine the cam and lifters.


Thanks for all your help.



Richard

[vanzen]

Dropping the oil pan will provide a view,
however, since you are planning a top-end rebuild anyway ...
you will find that pulling the jugs and lifters at that time
will be an easy enough task
leaving all the relevant bits in the clear for scrutiny –
the peace of mind a close inspection provides is priceless.

Even given the "shared drain pan" scenario –
pieces of that size in the oil would:
1) scare me
2) keep me from running the engine till I was 100% certain of it's integrity, and
3) be the only reason I would need to "tear it down".