Procedure for changing the belts on a 1996 Ducati 916

 

1.
Where are the belts?, behind all that stuff !!
2.
Remove the battery, the battery tray and pull the wires out of the way..
3.
Remove the fuel tank, the quick detach couplings help.
4.
Remove the 2 induction trumpets, 1/4 turn frees them off.
5.
Remove the air box
6.
Remove the black crank case breather to give more room behind the head, plus take out the spark plugs.
7.
Better view now ( crank case breather not yet removed ! )
8.
Having removed the spark plugs you can now put the bike in top gear and then turn over the engine by turning the back wheel. Note, always turn the engine the correct way, never backwards.

Next line up the timing mark on the end of the crankshaft.

p.s. Those yellow charging wires may need replacing  :-( 

9.
When you are at the correct timing mark, TDC on the firing stroke of the horizontal cylinder, all the marks will line up.

Horizontal head. "o" timing mark on the head.

10.
Vertical head. "v" timing mark on the head.
11.
Next you have to go around to the window on the left hand side of the engine to fine tune the alignment. You can remove this other cover to turn the engine over with a special tool, or a long bolt and lock nuts, but I found the back wheel just as good.
12.
The timing mark
13.
Next take off the tensioning pulley from each cylinder and remove both belts.
14.
Note how the right hand intake sprocket has spun around on the vertical head when the belt is removed.
15.
This is the belt for the early 916 & 748. Make sure yours has the RED writing.
16.
Next comes the clever bit. Mark up your belts using Tip-Ex. This makes checking the alignment very easy. On the vertical belt put the bottom mark on the back of the belt as well, otherwise you can not re check the mark when the other belt is in place.

Hint, go back to No.10 above and count the 12 teeth (it's 13 if you count both marks but then the maths below totalling 95 will not work)

For more details check out the Ducatitech website  http://www.ducatitech.com/4v/maint/belts/index.html 

17.
Belts back on.

The tricky vertical RH sprocket is not a big problem, as the white marks make sure all the timing marks are right.

Once the belts are on you then put the tensioning pulleys back on and take up the slack.

18.
Turn the engine over a couple of times to take out any slack, then  re-align the timing marks. This time the white marks on the belts may be in the wrong places. This does not matter as all we want is TDC on the firing stroke of the horizontal cylinder.

Next you need to set the tension of the belts, turn the tensioning pulley anti clockwise to make the belts tighter.

Replace the wavy washer and locking nut on the tensioning pulleys with new ones.

19.
There are lots of different methods of checking the tension. Try them all to double check your tension.

45 degrees of twist on the longest run of belt. Note this is a 1/4 turn NOT a 1/2 turn or 90 degrees !! 

20.
The Facom tool is about 1/4 price of the Ducati tool. I had mine checked first against a Ducati one. Ducati John (John Cellier) http://www.ducati-john.co.uk/ did it for me. You need to use the No.4 spacer, not the No.5 that the Facom guide suggests. Plus you go for the bottom of the top grove.
21.
Finally I used the 5mm slack method. I used the push up method, as suggested by Ducati John and some other websites.

In  the picture below you will see that a 5mm Allen key just fits between the top of the belt and the bottom lip of the head casing. 

All you need to do is push up, taking up the slack in the belt, and see how far you go.

You may wonder how hard to push. I found the best method is to push up and down multiple times (rocking). You then start to get an average distance, which takes out all the over and under pushing, if you understand me :-)

22.
Don't forget you check the horizontal cylinder first, while all the timing marks are lined up. You then have to turn the engine over 270 degrees, to the other timing mark in the window on the LH side of the engine, before you can check the vertical cylinder. At this engine mark it may be that none of the timing marks on the pulleys will be correct.

The reason you have to turn the engine over is that it then places the vertical cylinder at TDC on the firing stroke, which takes the turning force off the RH side inlet sprocket, which would otherwise place extra tension on the belt. Remember how the sprocket spun around in the picture at No.14 above?

All done.

Make sure you turn over the engine a few more times using the back wheel. This is to double check that the timing is right and nothing is hitting. It does not harm to double check the tension after a few more turns, just to make sure all is OK.