Ducati Sporting Club UK > DesmoDue Race Series > DesmoDue - General Questions and Chat > Timing Belts

[Spjallen]

I've bought them now, I'm sure they'll be fine. Seems a fairly simple job, line up the dots, belts off, belts on and tension. I'm sure it can't be that easy I must be missing something. Any tips?

[dunlop0_1]

When all the dots are lined up only the horizontal belt is at TDC
Make sure you turn the vertical belt to TDC before you tension it.

Turn it all over by hand and re check the tension.

[Spjallen]

How do you know the vertical cylinder is at tdc? I think its with the fly wheel and window on the alternator cover, I've just had the flywheel off doing the gear change lever and did not line anything up when I put it back on. I'm thinking oh *h*t! Why do you have to turn it to tdc before tensioning?

[skidlids]

Originally Posted by Spjallen

How do you know the vertical cylinder is at tdc? Not the just lining up the dots on that one? Why do you have to turn it to tdc before tensioning?

Its good practice to do them both at TDC, take the plugs out to see when the vertical piston is approaching TDC also makes turning the engine a lot easier

Turn the engine with the back wheel with the bike in gear on a paddock stand,
TDC Timing marks can be seen on the flywheel through the window in the alternator cover

[Spjallen]

Think I've worked it out. The flywheel has a punch mark which I should have aligned with the crank. Pants!!

[dunlop0_1]

Originally Posted by Spjallen

Think I've worked it out. The flywheel has a punch mark which I should have aligned with the crank. Pants!!

You could leave if you want. Line the pully dots up and fit the belts. Tension the horizontal belt. Stick a straw in the spark plug hole of the vertical belt. Turn the engine by hand/wheel until tdc is reached, your best guess will do. The dot on the pully will be roughly around 5 oclock. Tension the belt.

Basically it's to avoid getting a false tension on the belt because the helper springs can apply some pressure on the belt if it's not a tdc.

[Ghost]

Don't forget that there are two TDC's per cycle firing and exhaust. Really will pee you off if you time time it on the exhaust stroke.

[Spjallen]

Thanks Pieman. Ghost, you're not helping!!

[dunlop0_1]

You have compression stroke up to tdc (Combustion / both valves fully closed) this is the one you want.

Then the exhaust stroke which at tdc would have the exhaust valve open/closing ish.

Something like that anyway

[Ghost]

I don't get a false tension, cos I throw those silly hindrance springs away. I have a bucket full of them if anyone needs any.