what wrong with this monster

linearpower · August 27, 2010, 09:56:04 PM

ok... the monster makes this metal on metal sound when running... seems to happen on the stroke of the piston...

Diagnositics: pulled the plugs... turned the rear wheel bike in gear... no metallic sound... no piston hitting the valves... nothing...
checked the belts... tension is good... markings line up... Top End seems ok... at first glance
Run the bike with only the front plug in.... makes the noise...
Run the bike with the only the rear plug in... makes the noise...
but turn the bike over with no plugs in and there is compression and no metallic noise....

What might this be?

?
and lastly... what about it being a loose alternator nut....

?

linearpower · August 27, 2010, 09:58:48 PM

oh and anyone in NYC/manhattan who might have some input... that's where this bike is being pulled apart at the moment.... but any input is good input at this stage...

DoubleEagle · August 27, 2010, 10:09:05 PM

The sound of a dry clutch ?

Dolph

Raux · August 27, 2010, 11:28:59 PM

bad bearings on con rods?

Ddan · August 28, 2010, 01:40:41 AM

Check the belts. You can be one tooth off and not hear anything turning the motor by hand but there will be contact when it's running.

linearpower · August 28, 2010, 09:01:53 AM

whoops sorry about posting it in the wrong place... figured it was general since I wasn't able to be specific about what was wrong...

anyway... the belt tension was good and it looked like the belts lined up when we pulled the covers... I guess its possible that things are off by one tooth but it didn't look that way... I'll recheck that when I go into the garage today...

Speeddog · August 28, 2010, 09:02:52 AM

What year and model of Monster is it?
How many miles on it?
Can you describe the noise in a bit more detail?

linearpower · August 30, 2010, 02:32:10 PM

Hey yeah sure...

So the bike is a 2000 M900Sie... it has about 8300 miles on it...
The noise sounds like a metaling clanking when the bike is turned over... sort of moves in time with the piston stroke it sounds like... its not constant... its sort of an in time clang sort of metal on metal sound... I have started in once or twice for a second for some knowledgable 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...

?

any thoughts?

Thanks

Speeddog · August 30, 2010, 04:07:26 PM

Has the bike run OK before, or is this a new bike to you?

Sounds like a rod bearing, from your description, but diagnosing sounds over the internet isn't reliable...

linearpower · August 30, 2010, 04:29:35 PM

yeah... I know it... diagnosing anything over the internet is tough... however... the bike has run really well before and I've had it for three years. There are the normal Monster things that came up but the motor has been strong and run well otherwise.

Speeddog · August 30, 2010, 06:08:21 PM

Good news is you don't have to drop the motor to pull the heads.

linearpower · September 01, 2010, 10:54:44 AM

yeah right... I don't have to pull the motor to drop the heads but in it seems to me that this is likely the problem and I'm going to wind up dropping the motor I think. I'll check the heads and see prior but I can't imagine what else it might be... It's makin me a little nuts... I'm down to bottom end problems as the last thing that makes sense as to what might be wrong.

News:

what wrong with this monster

Raux