Ducati Sporting Club UK > General > Idle Chat > I've lost my Belt Virginity!!!

[MJS]

Originally Posted by skidlids

Antony the Single cam ones are a doddle, bit more fun when its a Testastretta set up

So - how difficult are belts on a 996? Just read the article in this month's Performance Bikes and it makes it sound pretty straightforward, yet I read a step by step guide on another website which made it sound much more complicated...

[antonye]

Originally Posted by MJS

So - how difficult are belts on a 996?

In theory it should be no more difficult than the 2V belts, with the exception of the different run of the belt due to the extra cam.

The only difficult bit, imo, is knowing how tight the belt should be!

The guide I used said that it should be tight enough to just run a 5mm allen key between the belt and the tensioner pulley on the horizontal cylinder. I had a practise on the belts before taking them off to get a "fell" of this, and sure enough I couldn't get a 6mm allen key through but I could a 5mm key.

On the vertical you use a 6mm key, and again it felt the same as using a 5mm key on the horizontal.

There's also the "twist" method, where you should be able to twist the belt to a maximum of 45deg at the mid-point between the tensioner and the cam pulley. I also checked this and it seemed fine.

You can also use a sonic method - "strum" the belt and see what frequency it is. The tighter the belt the higher the frequency. Unfortunately I couldn't get consistent results with any of the microphones I could find!

I don't have a tension checker, so couldn't test that.

Having a cam locking tool should make things a lot easier on my 748, and luckily I have quite a few of those knocking about

[Gbyte666]

Kev ( Skids ) did my belts on the 996 last weekend. An all I can say is I wont be having a go at that unless I had the freq meter that Kev had to get the belt at the exact tension at every point. Bloody clever stuff. Just like DD has taught me to actually have a go like Ant has done. But belts... hmmmm can I pratice on Bradders bike first rather than my own.

Craig

[MJS]

Originally Posted by antonye

Having a cam locking tool should make things a lot easier on my 748, and luckily I have quite a few of those knocking about

Is it really necessary to lock the cams? Surely if they move when you take the old belt off, it's just a case of lining the timing marks up again and making sure there are the right no. of teeth between each mark?

[antonye]

Originally Posted by MJS

Is it really necessary to lock the cams? Surely if they move when you take the old belt off, it's just a case of lining the timing marks up again and making sure there are the right no. of teeth between each mark?

Yes, but some of them will be under tension so they don't want to stay in the same place when you let go!

[Ghost]

Originally Posted by MJS

Is it really necessary to lock the cams? Surely if they move when you take the old belt off, it's just a case of lining the timing marks up again and making sure there are the right no. of teeth between each mark?

The testiclestretcher engine does not have timing marks, so when the front pot is at TDC on the firing stroke, the valves are closed and relaxed, but the vert is partway down the bore on its induction stroke and the wheels move considerably under spring pressure.

So mark the wheels and the belts, then transfer those marks to the new belts.

I then use a cheapo mic with freebie software to measure the frequency, at TDC, firing stroke, on each cylinder.

[skidlids]

And on the Testastrettas you are supposed to loosen the cam pulley bolts so that they can move freely when tensioning the belts with the cams locked in position, so good fun without any timing marks

[skidlids]

Originally Posted by MJS

So - how difficult are belts on a 996?

Easier than a Testastretta