Cam Timing Setup - Degreeing Hayabusa Cams

To degree the cams I needed to set the lobe centres for both the intake and exhaust cams to the required setting. For my cams I am looking for settings of 104 degrees on the intake and 106 degrees on the exhaust.

First I fitted a plate to the top of the cam housings and used the cam cover screws to hold in place. The plate is to provide a sturdy base for the magnetic stand. Next I fitted the SPI dial gauge with an extension rod to to the base. I then completed the following steps to degree the cams:

1. Fitted the dial gauge on plate near the intake cam. 
2. Adjusted the indicator so that the extension rod rests on the cam bucket and did not touch the casing or the cam.
3. Rotated the engine until the end lobe on the intake cam was on maximum lift.
4. Adjusted the dial gauge so that it read a level of 0 with the cam at full lift.
5. Rotated the engine a couple of times and watched the gauge wind up and then settle back down to a reading of 0.
6. To check the lobe centre I always rotated the engine in the running direction.
7. First I rotated the engine until the gauge read 0.040' off maximum lift and then recorded the reading from the degree wheel.
8. Next I continued to rotate the engine past 0 and then to 0.040' past the maximum lift and again recorded the reading from the degree wheel.
9. To calculate the lobe centre I need to add the two readings and then divide by 2 to get the lobe centre reading.
10. So for example, readings of 141 and 68 added together and divided by 2 makes 104.5 degrees
11. To adjust the setting I loosened the intake cam sprocket and rotated the cam a small amount, then re-tightened and re tested.
12. I repeated steps 7 to 11 until I managed to get a lobe centre reading of 104 degrees on the inlet. The final readings were 140 and 68 which made 104 degrees.
13. To set the exhaust cam I repeated the same steps as 1 to 12 now on the exhaust cam. I again  recorded the readings. On the exhaust cam I finally managed to get a reading of 106 degrees. The final readings were 66 and 146 which made 106 degrees.
14. Finally when everything was set correctly I thread locked the cam wheel bolts.

This exercise took many hours and a very small change on the cam sprocket made quite a large difference to the cam degree setting. I ended up making very small changes and recording every change I made.

The whole exercise took a long time to get right and was quite rewarding in the end. Next time should be quicker now I have a better understanding of the process.

Cam Timing Setup - Setting TDC

When setting up the cam timing on the Hayabusa, first you need to set the engine to Top Dead Centre (TDC). The timing mark on the starter clutch and cover is a good starting point but does not take in to account manufacturing tolerances.

I completed the following to set the engine to true TDC:

1. Set the engine to TDC by aligning the timing marks on the starter clutch and casings. I used the mark I made previously on the magneto and engine casing.
2. Installed the degree wheel on the end of the crank using the 14mm bolt that fixes the starter clutch. Had to remove the clutch and starter covers to fit the degree wheel.
3. Attached a piece of wire to the engine casing and pointed the end to TDC on the degree wheel.
4. Rotated the engine with a socket on the magneto bolt, rotated until the wheel read about 90 off TDC.
5. Fitted the piston stop in cylinder 1 which is nearest the magneto end.
6. Rotated the engine in the running direction until it hit the stop, then recorded the reading on the degree wheel.
7. Rotated the engine in the opposite direction and then when it hit the stop, recorded the reading on the degree wheel.
8. The numbers I recorded were 38 and 40. These were then added together and then divided by 2 making 39.
9. With the piston stop in place, I rotated the engine to the end of travel and then adjusted the pointer wire slightly to read 39.
10. Rotated the engine in both directions and checked that the readings were 39.
11. Finally rotated the engine to read TDC on the degree wheel.