MZ/MuZ Riders

I was wondering: how long do points / contact breakers roughly last on an ETZ251/250, does anyone have an idea?

Just asking because I cannot remember when/if I ever changed them.

lot of the life is how much current is used and at what voltage

the term to look at is Dwell how long the points are closed and the coil is powered

and how is the quality of the capacitor

dave

link is for 12volt systems
http://www.geocities.ws/loudgpz/GPZheiModForPoints.html

http://www.gofastforless.com/

have fun reading

A few variables here I would say - has the little felt pad being been kept lubricated.

If not then in theory the heel of the points might wear quicker.

Are you using electronic ignition? if you are the current through the points would be greatly reduced so the points would last longer.

I would say, given how much points cost, any doubt just replace them, but then again the old addage applies "if it aint broke dont fix it"

And at last it depends on which contact breaker you use:

-"Normal " original
-Original with "Pertinax" material
-Reproduction

Thanks for your replies.

Yes Guesi, I thought you might say that. Of course it depends on which breakers they are. But assume they are the ones originally fitted in my case, but if you could give an indication for the different types that would be helpful.

Andy, yes, felt pad has been kept lubricated, and no, there is no electronic ignition (it uses these points / contact breakers for that - original electric system, '89 ETZ251).

David, I guess the voltage is in the order of 10kV, with short yet rather enthusiastic bursts of current, and that the capacitor is in good order.

I know there are 2 places the breakers wear:
- at the contact points, where the spark causes burning-in, i.e. tiny metal particles taken off by the current in the spark (and not actually so much 'burned' in the sense of oxidised = chemically combined with oxygen, because of the alloy used). The capacitor (=condenser) will reduce the high frequency component of the current, which is the most energy-rich, hence it extends the life of the points.
- at the contact ridge, which follows the cam, being pressed down onto it by the spring - just ordinary wear. Less if well lubricated, and if your cam is nice & smooth. A rough or corroded cam will eat your cam follower ridge in short order.

The background of my question is that I cannot remember ever having replaced these points, on this bike. What I do is sand the points so they keep a smooth surface, adjust the lot & lube the felt. Now I might have forgotten that I replaced them (had the bike for over 20 years now), but also: you replace points before they fail, so they are then still in working order, and then I normally keep the old ones (as they can help you in a bind, and take up no space). Yet I have none for this bike. So that leads me to believe that I never replaced them. But the bike is well on the way to the 33k mile mark (25k with me), so that made me wonder: is it possible that these are the original ones? On a car, when they still used points, this could be a normal replacement mileage, but on an ETZ?

So I'm just looking for a number.

I've only replaced it on the MZ once, and that was because one of the contacts on the points fell off one day. The only discernable difference that made to running was a wavey idle.

I have replaced points on my car once too.

Lets make it simple: The contact brakers last as long as they last.

If I should make a "hit-parade" of the parts:

1.Pertinax
2. Normal Originals
3. Reproduction.

The exact time or mileage depends on so many circumstances that it is impossible to give an exact answer ...

Thanks Guesi, yes, I guess we should expect a positive correlation between price, and quality & longevity.

And yes, they last as long as they last, but that applies to everything. But how long is that, roughly?? (In terms of mileage - if they're not used they'll last forever)

Is 33k miles possible?

I would say anywhere between 15-30 really..

My last set lasted 20k if they were the original set. And my current set I have on now is at the 10k mark almost.

So, I think it's possible to get to 33k..

Sorry, but I don´t understand the use of such a discussion.

There are so many influences to the lifetime of a contact breaker that you cannot predict its lifetime.

If it is worn out, I change it. No matter how long it lasted...

Or change to an electronic ignition

We all can be lucky if this is one of our biggest problems with our MZ bikes

Guesi wrote:
Or change to an electronic ignition

We all can be lucky if this is one of our biggest problems with our MZ bikes

Not in my case.

Of course it's a pointless discussion - it's just chatting. I just wondered if I should get a spare set, and I think I know. We could also re-focus to address the meaning of life, or try to solve the issue of the sun heating up & expanding.

On the electronic ignition: my ignition is completely original, and I am quite pleased with how reliable that has been, and how well it works. Yes, you have to adjust the points from time to time (unlike an electronic ignition), but that's fine as you have to take that cover off anyway, to look at the chain & lube it.