Hi all, Wanting to get my scooter back to "like new" performance I've installed a digital rev counter (from Dr.Pulley) in my Sym VS125 (H6T version) to help tuning. Refresh interval is stock at 0.5s, hot idle sounds steady showing approx 1580 varying from 1560 to 1610 and pulling a slight uphill at 60kph shows approx 6000 varying between 5700 and 6300 rpm each second.
These display differences seem big to me and I cannot detect any audible changes at the same time but my ears are getting dodgy I know ;-(
ps: the supplied cable was too short for fitting inside bodywork so I added 40cm of a similar two core cable by soldering. Readings were checked and found to be identical before and after hiding inside bodywork. I think that the only high voltage that can be detected comes from the coil->plug-cap cable so passing the rev counter cable near to the CDI should change nothing.
Are these readings in the normal expected range? If not what's to check and how? If I have dodgy high rev sparks, that could explain a possible top end power lack?
I'm not often at more than 60kph, strict town limits here but some hills, I climb from 400m altitude to 700m on my 4km home run.
I bought an inexpensive tach last year, and got what I paid for. The readings are imprecise, and the display lags -- doesn't adjust until a few seconds after I add throttle. It's driven by the very high voltage pulse going to the plug, so I don't think anything coming out of the CDI at far lower voltage would affect it. The way I understand it, the signal from the CDI is nothing but a low-voltage "tweak" that says "OK coil, time to do your thing."