Martyn,
Here is my reply from another post:
"The new BT-H can vary as much as 9 derees ( at least mine does) with the rod in place when setting the timing. If the rod is slipped in the center of the armature (and threaded hole), you with be able to move the crank 4.5 degrees on either side of TDC as everything takes up the clearances. Because I was trying to do repeatable runs I needed to know more exactly where the spark was firing. I checked the timing with a
strobe and found that after you slip the rod through the armature you need to move the wheel in the direction of travel to take up all the slack on the rod. On mine, this is where the spark was firing, i.e. not the 4.5 degrees earlier when the rod can slip in or out with ease. I do not think these numbers matter to you, but I mention them to urge you to pick a way of setting the timing that will be repeatable by you with ease. Then you will at least be consistent."
I have used the Grosset device mentioned here and above. I have also strobed the bike with the oil pouring out of the quill. It is messy, but if the engine is warmed up the roller bearings will not be damaged for running without a supply for a few minutes because thew will contain plenty of oil. On my racer I have a dry clutch so I have marked the engine pully and I have a little pointer that I bolt on.
I think if you set the timing as I have mentioned in the quote, you can strobe it once to verify the method you should use statically to get the best result. An old /2 BMW pushrod fits inside the crank end. If you slit the end going in the crank and put a ground nut on the end of a threaded rod that goes through the pushrod tube you can tighten it until it is snug as the ground nut will spread the slotted end of the tube. You can use any tubing that fits of can be turned to fit in the crank end.
Grosset uses a CD disc for the degree wheel. So he machined a little adaptor to thread on the end of the tube to hold the CD. I scaled a drawing of a degree wheel on my computer and printed it on sticky backed paper, then applied it to the CD so I had a full 360 degrees. Grosset just gives you a small range. If you wish a copy of the scaled drawing, just send me an email at
daviddunfey@aol.com.
You want to strobe it at the RPMs where it is fully advanced. Without a tach you can just watch and see where it stops advancing as you rev. I think it is quite high on the BT-H compared to the Pazon. There is a graph on the BT-H site that shows the curve.
David
