Researching what type of hall effect sensor to buy

[fonque]

I am researching my first efi conversion project. I am a bit stuck on how to trigger this system. I am trying to convert a 1980 honda cx500 custom. The issue is I only have 1 area I can stick a trigger wheel on the back side of the crank where the advance pulsar used to sit. If I attach a trigger wheel to the back of the crank the gear can have a diameter of about 2 inches. If I cut a trigger wheel that small with 17 or 34 teeth, will that be too small for hall sensor to read?

here is the OEM pulsar as a frame of reference. The gear would sit inside the ring.
http://www.ebay.com/itm/79-Honda-CX-500 ... 3e&vxp=mtr

I did a quick search on digikey and from what I could find that could fit in that area, it seems that the gear tooth spacing and depth wouldnt work.
Does anyone have any insight on this? Any help is appreciated.

[jsmcortina]

You might be better off aiming for a lower tooth count and using a VR sensor.

James

[dontz125]

It looks like the existing rig is already VR. What you might do, instead of cutting teeth, is to drill spots - the Yamaha FZR1000, YZF750, and YZF1000 used this method. Use an 8-1 or 12-3 pattern.



Obviously, instead of drilling on the face, you'd drill on the perimeter ...