Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Plus 4 Speedo again

Well, Omnitec panel out and ditched! Just got to get this darned speedo back into commission. Great groundwork done by Dave W saved me a lot time and got me well up the learning curve. My understanding (from Caerbont) is that the speedo wiring goes via the "Caerbont Unit" although only bus wired thro', no signal processing.....so therefore you could wire the probe direct to Speedo.
I've checked the probe, and with a 12V supply to it I'm seeing operation of the LED at the probe whIch indicates to me that the probe is OK. By the way I'm seeing 4 flashes for one rev of the front wheel, this may be my problem!?!
I've wired the probe upto the speedo in accordance with a drawing / instructions kindly forwarded by Caerbont, who said the haven't published the Morgan type speedo info online (I thought they had but I couldn't find it).
I've only carried a spin of the wheel with car jacked up but can't get a kick out of the speedo as Dave did with his 10 bolt sensing, it would appear that I have only 4 pick up points so maybe my low down speed sensing is not too good, I can't recall, all I know is that the speedo was working with some reasonable accuracy at all normal speeds. Has anybody had a similar issue. Just a heads up, Caerbont did mention the bus tracks in thier unit could fail, new one on me however, direct wiring would negate this.

The sensor should be picking up the brake disc bolt heads so 4 would be surprising. I had 5 on my "retrofit" instead of Dave's 10 on OEM and it worked fine from about 5 mph.

Thanks Bob, I'll recheck tomorrow (am i loosing completely, I'll count again). Even got me thinking when I updated the the brakes with the Mulberry kit ages ago, did I swap the discs and carriers around?....dont think so! But even if I did the speedo been working fine,
Rgds
Bm

Bob, just an aside, did you carry out a speedo calibration as per the Caerbont procedure, inputting the pulses per mile for your particular wheel tyre set up, i.e. measure how far the wheel travels in one rev (In inches) divide the result by 63360 (ins/mile) to get revs/mile, finally multiplying by the number of pulses/rev to get pulses per mile, then inputting this into the speedo using the Caerbont cal' procedure. I'm guessing may be not, if you didn't have the procedure. That's my next check, have I lost the original calibration whilst "fiddling"? hayho onward and upward
Bm