Topic: Wiring up a Danmoto gauge

[Duke McDukiedook]

On the cap value I would think you would just need a filter value to shelve the RF noise at the desired frequency. What that Farad value would be I could not tell you. Yeah, coiling wire would not make a capacitor but it would make a free air inductor.

[Scott S]

 After fiddling with the bike today, tuning the carbs and getting some heat into the engine, the tach really calmed down. Most, if not all, of the noise went away. It was idling in the driveway and two bars were showing....a nice, steady idle.

 It's certainly not bad enough to bother me at this point. It seems to be working fine now.
 All that's left is to program the speedo.

[scottly]

Yes, I need a bigger capacitor.
 Someone said to try an electrolytic radial cap in the range of 1000-10,000uf. Or, since the ones I have came in a two pack, wire another up in series?

A 10,000 uf cap is HUGE. Try wiring the second cap in parallel with the first one. Caps add in parallel, the opposite of resistors that add in series. 

[Duke McDukiedook]

Yeah, you would want to talk to an elcectronics guru on RF noise supression but I would think a cap around the size of .01uF would be a better place to start for a noise filter.

[Scott S]

 Now that the bike is running and the battery is fully charged, I'm not getting any noise. The tach works well and is very steady.

 I also programmed the speedo today and set it to MPH. Haven't verified it yet against a known speedometer, but it seems to be OK.

 Good gauge, good price and not that hard to wire up and program. I can see using this again on a different project.

[K3Owner]

Wire is measured in impedance by gauge and length. If you know both, you can look it up easily enough. It's not the impedance that is playing the role. It's an RF choke, absorbing the noise. A cap in that range should work well, is very cheap, small, and easy to hide in the wiring. Doubling those little ceramics won't give you enough effect. 500 of them will, though. As I said, advice from someone not on the bench for 20 years. Cheap advice but at least it's a cheap part to try!

[Scott S]

 It's working great now. Only about 50-60 miles on the bike, but so far - so good.