Loose 2V cam belts and valve clatter

[rettedm]

New to me 2001 M750. Bike has a significant amount of mechanicall clatter that sounds like valves. In replacing the belts I found them very loose (can get my little finger between the belt and the idler pulley!

Will loose belts create valve train noise? (Seems that it should) Or do I have another problem?

Bike has very low miles (3500).

Thanks, Dave

[Jobu]

New to me 2001 M750. Bike has a significant amount of mechanicall clatter that sounds like valves. In replacing the belts I found them very loose (can get my little finger between the belt and the idler pulley!

Will loose belts create valve train noise? (Seems that it should) Or do I have another problem?

Bike has very low miles (3500).

Thanks, Dave

Loose belts won't cause a problem unless they are loose to the point that they jump teeth on the cam/crank pulley.  This will quickly lead to bent valves.  A loose belt won't cause any excess noise if the timing is correct.

If your hearing some valve clatter other than the normal Desmo sound, then you might have a slightly bent valve.  You might want to get the 6K service done a bit early, especially if you're not familiar with Ducati engines.  They tend to have a lot more chatter than an inline four.

If you want to troubleshoot yourself, first place to start is a compression test.

Also, does the bike run well?

[Howie]

Loose belts will not cause valve clatter.  Is some valve clatter normal? Yes.  Is yours? Dunno, can't hear it.  Find a local educated ear.  '01 bike with very low miles?  If the belts are over two years old, change them now.  This would also be a good time to check valve clearances.

[CairnsDuc]

It was an adjustment for coming from the Japanese bike world how much chatter and noise the Ducati's make, I kept thinking something was not right, but everytime I visited my trusty Mechanic he said it was quite normal and to enjoy it.

He fired up some other Ducati's in the showroom so I could listen to the assorted noises, I am used to it now, but by comparison, My early Kawasaki and Honda were silent next to the S2R.

But love the Desmo noise! 

[Gearhead211]

 [coffee]Valvetrain noise is normal on the desmo twins, the lack of springs and the extra cam lobes and rocker arms add to the symphony.  As for the belts, you should be able to wiggle a fingertip in between the belt and the idler.  The belts should be tight enough to remove all slack but not stretched.  If it feels like a guitar string its too tight.  Since your bike is an 01 if the belts have not been changed then change them now, my service manual says every 12000 mi. or 6 years whichever comes first also make sure your idler wheels spin freely and replace any that don't.  Do not try to lube them up, they are sealed bearings and you don't want any oil or grease getting on the belts as it will deteriorate them.  Valve adjustment should be done at 6000 mi.

Maybe this will help?

[He Man]

[coffee]Valvetrain noise is normal on the desmo twins, the lack of springs and the extra cam lobes and rocker arms add to the symphony.  As for the belts, you should be able to wiggle a fingertip in between the belt and the idler.  The belts should be tight enough to remove all slack but not stretched.  If it feels like a guitar string its too tight.  Since your bike is an 01 if the belts have not been changed then change them now, my service manual says every 12000 mi. or 6 years whichever comes first also make sure your idler wheels spin freely and replace any that don't.  Do not try to lube them up, they are sealed bearings and you don't want any oil or grease getting on the belts as it will deteriorate them.  Valve adjustment should be done at 6000 mi.

Maybe this will help?

12k or 2 years.

[Desmo Demon]

Yes, 12k miles or 2 years, whichever comes first is what is recommended, but you will hear all sorts of preferences, like I usually go 12k or 3 years, but have gone only 6000 miles and five years....I know a guy who went 20k miles and six years.  In a way, it is subjective to a person's comfort zone.

As for belt looseness, if the belts are too loose, you can run the risk of the belts slapping the inside of the belt covers when the engine is cold and you chop the throttle. This will start chewing into the back side of the belt where it slaps the cover. In general, you should have no more than 5mm distance between the fixed tensioner and the belt when cold. Some people recommend running 6mm on the vertical and 5mm on the horizontal since the vertical cylinder tends to run a little hotter. A good page on setting the belt tension on a Monster can be found here...

http://www.ducatisuite.com/belttension.html

[rettedm]

Thanks for all the comments. I replaced the belts and adjusted tension properly and the valve clatter is gone. Sounds like a big sewing machine now!
Valve clearance is next.

Dave