Topic: Need help with an old timing light and tachometer

[elquenada]

i picked up an old timing light and tachometer/dwell meter on ebay a few weeks ago for $30.  I just got to try them out today on my cb550 (1975) and had poor results.  Now Im wondering if I hooked them up wrong.

The timing light was kindof working but I assume its old and the inductive pickup is not in great condition.  I connected the red/black cables to the battery and the inductive pickup over the spark plug wire.  I tried different parts of the wire and got varying results; it flickered but not very regularly.

The tachometer (a analog sears brand tach about 30-40 years old) didnt work at all.  I follow the instructions but no dice.  I hooked up the black lead to the battery ground and the green lead to what I thought was the switchable 12V at the coil (2 spliced black/white wires?) but got nothing at all.  I think i made a good connection to the 12V but truthfully it was hard to get at so maybe that was my problem.  I have a Dyna S ignition system installed so I couldn't find a spot to clip on to under the points cover.

end of story.  sorry for the mini book.  any advice would be helpful.  I especially want to get the tach working because the one on my bike does not seems acurate at all.
TIA

[w1sa]

How good does your engine run? What model bike?
Could it be that your ignition electrics are in a worse state than the strobe and tach?........spark leads and caps, coil/connections........just asking 

[elquenada]

thanks for the response. 

the bike (as it says in my original post by the way ) is a 1975 cb550 and its running pretty strong.  It could use a few gaskets but I generally never have electric problems.  The bike starts and runs on the 1rst or second try every time.