Adusting the Cam timing

One of the best things with our Bevels is that to get the camshafts to the angle that we want costs us nothing more then some time. On the bevels the cam drive system is very accurate and it is fully adjustable. Much easier to adjust then on a rubber band Ducati. To get acces to the adjustment the alternator rotor has to come off and ofcorse the cam drive gears has to be removed. Here is an explination how/why it is possible to adjust the cam timing. The crankshaft has a gear that has 24 teeth. This drives a gear that has 36 teeth. The 36 teeth gear has another gear on the back side that has 23 teeths. If we adjust the first gear one teeth we will do as follows 360/24=15. This means that if we move the crankshaft driven gear one tooth we will change the cam timing 15 dregrees. If we will change the second part (23 teeth inner part) of the 36/23 gear one tooth it will be as follows 36/24*360/23=23,478 degrees. The reason for this is that the primary gear ratio is 24/36 so the second gear rotates with 2/3 of the crank speed. Then you have this 2/3 speed gear with 23 teeth and it will end up  at 23,478 degrees. This means that if we combin this two posibilities to adjust we have a possibility to adjust the cam timing down to 0,65 degrees as the smalles adjustment. That is not bad. On a rubberband Ducatis the smalles adjustment with offset keys are 2 degrees. The offset keys are also very expensive. Here it is for free. It only costs a bit of thinking and a small bit of work. I made a Excel sheet to make the adjustments easier. It might look a bit confusing but it is actually very easy. The left side of the graph tells how many teeth that should be turned at the 36 teeth gear and the top side of the graph tells how many teeth that should be turned at the 23 teeth gear. Just find the value that is closest to whet you need. For my bike I needed 4,25 for the front and and 6,25 degrees for the rear cylinder. 4,25 is close to 4,56 so that means the 36 teeth gear CCW 5 teeth and the 23 teeth 3 teeth CW. What this does is 5*15=75 minus 3*23,478=70,434.          75-70,434=4,566 degrees. The reason that it is CCW and CW and not CW and CCW is that I want  to retard my timing. For the rear we want 6,25 degrees and that is close to 6,52 degrees. That means 36 teeth two teeth CCW and the 23 teeth gear 1 tooth CW. This gives 2*15=30 minus 1*23,478 degrees=6,552 degrees.    Not dificult at all. Very easy.

Before adjustment

The actual adjustment

After adjustment. I did some marks to identify were the timing should be

Not easy to see but the bevel gear is still sort of in the normal position. Only one teeth away from the markings

This is still unchanged

Thats all. Now it is just re install the things to double check the timing to make sure that it was not done in the wrong direction or that it was and calculation failures done. Install the alternator rotor and the covers and of you go for a ride happely smiling with your improved Ducati.

Back to checking the Cam timing

Done. What do you like my wallpapers by the way. Nice isnt it!!!!!!!!

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