How can I count pulses with a DSO5102P

[oldiemotors]

I need to count the number of pulses generated by the vehicle speed sensor on a Harley Davidson for one revolution of the wheel.  When I connect my scope I can see the pulses being generated as I spin the wheel, but it is difficult to watch my mark on the tire and visually count the pulses at the same time.  Just wondering if I can place my scope into acquisition mode, spin the tire once, stop the acquisition, and then go count the pulses.  Or is there an even better way like counting the number of triggers?  Any ideas?

[Kean]

Use a reflection sensor (cheap on ebay) and a strip of white/shiny tape on the tire.  Feed that into your scopes second channel to use as a reference.