First Time Using a Digital Dwell Meter - What Am I Doing Wrong?

[BlueR32]

As suggested in a different post, I got hold of a digital dwell meter to set the points gap on my 1977 XS650D.
https://www.amazon.com/dp/B079P6D4PC?psc=1&ref=ppx_yo2ov_dt_b_product_details
I set the Meter to 4-Cyl Dwell and connected it up - black lead to ground and red lead to the points wire. Fired up the bike and the digital readout jumped around a lot from about 17 to 35 but I noticed a somewhat regular reading of 24 or thereabouts. Is it normal for the readings to jump around like this or am I doing something wrong?

 

[5twins]

On an old used set of points, yes, the reading can jump all around. Sometimes it's difficult to even use the meter on them. New points usually give a nice steady reading, well, good quality new ones, lol. I can't say about the Chinese knock-offs that are flooding the market now, I never tried any.

The spec, after doing the math, is 22° to 24.5° on the 4 cyl. scale (actual 2 cyl. value of 88° to 98° ÷ 4). Since the dwell meter reading is inversely related to the gap size (smaller number indicates bigger gap), your 24° reading is towards the small end of the gap range. I shoot for as large of an "in spec" gap as I can get (as close to 22° as possible) because the gap usually wears closed over time and this way, it will remain in spec longer.

 

[Melnic]

Have you hooked up a timing light and are you getting a steady position on the timing mark using the light?
Does the timing cam lobe have pitting on it? Any side to side play on the cam lobe?
I know my original points, the readings were a tad more sporatic than when I got new points.
I can imagine older points that have not been cleaned up and don't have straight smooth surface might be sporatic.

 

[ckahleer]

If your dwell is jumping around, timing will also. Make sure you have a good set of points.

 

[BlueR32]

I should have mentioned that the points are new (Daiichi DH-40). I also did hook up a timing light and I am getting a steady position on the marks.