HT lead tacho pickup?

[Robotstar5]

Had a Draper automotive DMM for a while and it's OK for most garage uses but the tacho function relies on connecting across the points, my latest bike is magneto so no points!. Looked for a cheaper version of this to plug in without any luck so far or would I be better off using a seperate unit like the Draper 79005 or similar?. Don't want to spend too much as it would get very little use.

 

[Pete.]

It won't work by connecting across the coil feed?

 

[Robotstar5]

It won't work by connecting across the coil feed?

The magneto drives a CDI unit so not sure what voltage level it fires into the coil - would it damage the DMM?

 

[wookie]

How about a Gunson Timestrobe ?

An old fashioned timing light, you just remove the HT lead off the sparkplug, and twist the spring onto sparkplug and the plug the HT lead onto the spring.

I've got one and it works fine, never tried on a magneto setup but I can't see why it wouldn't work with a magneto as it just senses the HT pulse.

 

[Robotstar5]

Would it work as a tacho?, I need something to monitor the RPM's while adjusting the carb.

 

[wookie]

Would it work as a tacho?, I need something to monitor the RPM's while adjusting the carb.

Ah sorry, my mistake I missed the bit about the tacho and thought you were trying to set the timing (I've got timing on the brain at the moment as I've been setting/adjusting it on one of my old cars). No it wouldn't work as a tacho, but just to prove a point what I suggested above does work, I've just tried it with an external battery on the lawn mower.

 

[armalites]

This does both jobs, £49

http://www.ebay.co.uk/itm/AccuSpark...202675?hash=item2803aa94b3:g:vGIAAOSweWVXc5eJ

 

[Robotstar5]

I hope the timing is OK as adjusting it involves removing the flywheel / magneto rotor which can be difficult according to the owners forum