Hi all

I'm currently in La Paz, Bolivia and been doing a major service on
my Yamaha Tenere 3AJ 1990. I started the bike to warm the oil
up before draining it and noticed for the first time a strange noise
that appears to be coming from the barrel. It sounds like a cross
between a mechanical scrape and a squelch and happens irregularly -
maybe every few strokes.
I tried using a screwdriver like a stethoscope to listen to the engine
but didn't hear the noise through the screwdriver. I tried with the
screwdriver on the non-camchain side of the barrel and was surprised I
didn't hear it there either. This gives me a little hope that maybe
the problem isn't with the piston/barrel but my naked ear says this is
where the noise is coming from.
We are at very high altitude and have not adjusted the carburettors,
so the bike has been struggling recently.
Usually when I do an oil change, I don't see any specks of aluminium,
but this time there were a few dozen left in the bottom of the oil
catch tray. I cut open the oil filter and there were many dozens of
specks of aluminium and lots of small blackish-brown specks too. (But
as I've never cut one open before, I have no idea whether this is new)
Since the start of this trip (a year & about 26,000 miles ago), the
bike has needed its oil topped up everyday (about 3 glugs from a 1
litre bottle).
The bike is still ticking over regularly, despite the noise. Pulling
the clutch in has no effect on the noise. The noise speeds up with
increased engine rpm. and doesn't go away once the engine is warm.
I'm wondering - before we go to a mechanic and have the top end
disassembled, is there anything else we should investigate first?
(e.g. cam chain and tensioner?)
I know this is a very vague description of the problem and doesn't
give people much to go on, but any thoughts would be greatly
appreciated.
All the best
Mark

You say it increases with rpm then it shouldn't be gearbox related. As you say the metal flecks are aluminium then I would be looking at aluminium/alloy parts that turn in relation to the engine ticker over as cams, valves, crank are all steel. Things like piston, area around cam chain. Oil pump ?

Compression test ?

Sorry not very specific but might help narrow the possibilities.

Thanks gixxer.rob for your thoughts.

I think I have now traced the noise to be coming from either rev counter cable drive gears, or broken rev counter cable. I now seem to have sorted it (after trying several different things). See this link to TenereUK forum for more details if you're interested!

The Ténéré Forum • View topic - 3AJ Tenere - strange engine noise - any ideas?

All the best
Mark