I have used Nisonger in the past, but got real tired of the attitude which seems to be based on the concept that the customer is always wrong. I also say that the quality of their work was, almost, always border line. I had them do a speedo which had quite a bit of bounce when I got it back, when I called them about the issue I was told about the 5000 other items that may have caused the new tach to bounce, to their credit they sent me prints of speedo cable claiming that the cable was, generally, always the culprit. When I explained that all these issues were covered with new parts and measurements. the guy finally told me that I could send it back, but if they didn't find anything wrong they would charge me a full fee, again. Phenomenal customer service, I couldn't pack the speedo up fast enough, NOT!
I found a service:
C/o Smith’s Magnetics
614 W. Campbell St.
Arlington Heights, IL 60005
Excellent work, no bounce! No BS and no attitude; I have had him do 2 pairs of instruments and rebuild two Smith's speedo drives; when they came back they were indistinguishable from new and worked with steady needles, with one exception; I had Scott do a speedo for my old Enfield Interceptor, it would turn the odometer, but not the speedometer. I gave it a rap which seemed to encourage it; the second time I rapped it the glass cracked; I called Scot about this and sent him the speedo, he returned it to me within 10 days with new glass and a properly responsive needle, no charge! The down side is that Scott is very pricey.
Palo Alto Speedometer, another good place, also pricey, they did up a tach and a speedo for my R90S, I do not know if they do Smith's:
718 Emerson St, Palo Alto, CA 94301
Phone: (650) 323-0243
I'm sure that you have many more choices, I 'd advise you to explore them before fattening the bank account of Nisonger's
The allure of a motorcycle is also it's bane