anyone good with Diagnostics

[linearpower]

Wanted to know if it was possible to make use of the SF Monster expertise... ?

Just curious... I'm here in NYC working on my bike and having issues with unfortunate metallic sounds in the motor when I run the bike... sounds like it comes in time with the pistons going through a full cycle.

Problem is... it doesn't seem to be piston on valves as the sound doesn't occur when I pull the plugs and rotate the pistons through a full stroke by putting it in gear and turning the rear wheel... weirdest thing ...

but I do get the sound when I only run one cylinder... doesn't matter which one, vertical or horizontal... disconnect the plug wire on one I get it in the other... soo... ummmmm

I'm down to checking the alternator nut next but not sure where else to look...?? heard this nut loosening up might do it...

Could still be connecting rod stuff but it doesn't happen when the plugs are out and I turn the wheel while it's in gear... I know the pistons aren't loaded and there's no heavy firing but you would think you'd get some sound in there when the plugs are out....  sounds fine when we did that though.

belts are good... marks line up...

Any thoughts...

[desmoquattro]

Did you drain the oil and look for metal bits?

[linearpower]

Thats my sunday evening plan mr Joe.... or afternoon ... while I'm watching motoGP at the garage...

[Michael Moore]

Sorry to hear that. I think we've got the same bike (2000 M900), so I'll be interested to hear what it is.

[mostrobelle]

My husband's M900 threw some sort of a bearing in the bottom end of his engine.  Made metallic noise when he rode it.  It required tearing the engine down and replacing the bearing.  It wasn't a catastrophic failure--the bike rode fine, but you could hear a stuff coming from the engine that sounded "not good".  That's all I've got...

[Drunken Monkey]

Alternator nut, spacer between the starter sprag and crank, loose bit...

The puzzling part is hearing the sound more when running on one cylinder, but that could be attributed to your bike making less noise so the sound is easier to hear.

You could always try the "poor man's stethoscope": take some rubber tubing, put one end next to your ear and use the other end to track down where the sound is coming from.

[Drunken Monkey]

Also, try derbying this in Tech

[linearpower]

Hey...

The noise sounds like a metaling clanking when the bike is turned over... Sounds like Mrs Mostrobella's husband had a similar thing going on... yeah mine runs fine but sounds like there is a blacksmith in there... I put this thread up in Tech just thought I would check the San Fran folks who have been so helpful in the past... and I'll keep you posted Michael...

Oh and did I neglect to say this motor only has 8300 miles on it... I thought it was odd that it would throw anything at that point... it did sit with the previous owner putting only 900 miles on it in 7 years though. The bike is realllllyyyyy clean for a 2000... and its well treated by me.

The sound sort of moves in time with the piston stroke it sounds like... its not a constant with no space... its sort of an in time clang sort of metal on metal sound... I have started it once or twice for a second for some knowledgeable folks  who feel its a thrown bearing... or rod.

Things I've done to diagnose so far... checked my clutch... fine... pulled the alternator cover to check the nut... fine and not loose...

pulled the plugs and cranked the bike... no noise at all... pulled one plug wire... noise... pulled other plug wire... noise...

drained the oil... no large metal on the drain plug magnet, nothing in the filter, screen, or oil that was drained...

not quite sure what to do next outside drop the motor and pull the heads and try to see if there is undue play in the pistons at that point...Huh??

any further thoughts?Huh?
Thanks