Setting points using dwell meter

[Sorf]

Ok, one for the mechanical minded. (which isn't me )
Just trying out the new fangled multi-meter on the timing. Now this is a "Digitor" meter with dwell settings in degrees. Has settings for No. of cylinders, eg, 2 cyl. - 4 cyl. etc.
So to set dwell to the 180 deg. as per the manual, I'm assuming that you count each set of points as 2 cyl.? Now, the start off reading on the meter is 180deg. and once I start the bike, the current reading is 123deg.
So now my problem, if I move the breakers to acheive a reading of 180deg. the points close up and the 2 cylinders cut out at a reading of approx. 150deg. and there is no way I can get to a 180deg. reading.

WTF am I doing wrong (other than working on the bike myself )
Help please.

[Pigford]

Sorf, all due respect for going with the 'dwell meter' approach, BUT:
If ur so keen to get the timing 'spot on' why on earth do you want to stick with a points set up?
Surely you'd be better off spending time & money on a decent electronic system, aka: Dyna, Newtronics, Boyer, etc!
Sorry I can't give any help setting points with a dwell meter, but good luck!
I'm sure one of the more edumakated members will assist you!

[Ed Z1-R]

No disrespect Sorf but im in the same camp as Pigford on this one

[Hack]

Sorf, stick with it, there's nothing wrong with points!

I think the problem is probably down to the manual for the multi-meter as these almost always assume that people only ever work on 4 stroke car engines equipped with a distributor. The issue here being that a distributor rotates at half the speed of the crankshaft unlike a Z1 which has two sets of points driven at true crankshaft speed employing the wasted spark principle (spark occurs at TDC on both compression and exhaust strokes).

So, back to basics, what you are actually trying to achieve here is a duty cycle of 50% (i.e. the points should be closed for half a revolution and open for half a revolution), which in the case of a Z1 crankshaft driven set of points can also be expressed as a dwell angle of 180 crankshaft degrees.

Your meter is actually measuring the duty cycle as a %age and then doing a calculation based on the number of cylinders you entered to display the reading as a dwell angle expressed in degrees of distributor rotation.

To convert a dwell angle expressed as distributor degrees to crankshaft degrees you need to multiply the meter reading by two. So with this set-up you are looking for a display of 90 degrees on your meter. This also explains why you could never achieve a display of 180 deg as this equates to 360 crankshaft degrees which means the points are permanently closed!

Another way round this issue is to tell the meter that you have a single cylinder engine (if it will let you), then you are looking for a display of 180 degrees.

Hope this helps, I?m off to the pub now!!

Andy

[Sorf]

Thanks Hack!
I knew that...........not
Sorry guys, just count me as one of them ?rivet counting Zed bore" mob
I can (easily) live with points. Just decided I'd best do it myself rather than paying someone else to do it, when after all, it's a fairly simple job..................when you're told how.

[Pigford]

Sorf, Hack, even tho' i prefer pointless ign, thanks for this thread, its very interesting and I've learnt a bit! Main lesson, steer clear of points, too complicated!

[Ed Z1-R]

Its up to the induvidual whats fitted, fair play Sorf my Z1-R ran on points for 4 years problem free i admit i never ever set them up( never had the tester and sometimes confusin) this was always left to a local and trusted mechanic, as i like pigford, found it interesting,and informative and learnt summat. its always better to learn and do things oneself as it brings so much personal satisfaction