1994 MZ 300 Saxon - Intermmitent running

[Phil69]

Hi, my first venture into this forum. I was wondering if anyone had any thoughts on the following 'interesting' problem concerning intermmitent running on a MZ 300 saxon which uses electronic ignition.
Symtoms:
The bike will start normally but runs for a varied amount of time before the engine dies.
Fuel & spark present.
Will often start and run again after the bike has been left.
Things tried so far:
New rebore, gaskets & piston rings.
Crankase seals replaced.
New spark plug (several tried).
Thought I'd try next:
Going through all the electrics bit by bit ie. new battery (although seems OK & charging OK); replacing electronic ignition (although not sure where to source this item); and spark plug lead.

Any thoughts on this issue would be very welcome, as would info on where I could source parts?
Thanks in advance, Phil.

[manumensa]

Hello and wellcome Phil !

You didn,t write carburator (are setting ok ). Also sound like a not enought fuel flow (fuel tank air vent blocked ) or choke open all time.

Have it mount a PVL system?
http://www.powerdynamo.biz/deu/systems/ ... vllima.jpg

Difficult to found spare parts for original electronic ignition like sensors.
http://s40205778.shoplite.de/sess/utn;j ... shopscript
Powerdynamo have a new e.i. but no cheap, my opinion you best test motorcycle with a electronic man before you buy.

Best Regards, Manuel.

[DAVID THOMPSON]

please note that
powerdynamo.biz is
a part of mz-b.de
and can be accessed at
http://www.mz-b.de where they show both parts and electrical stuff
dave

[djsbriscoe]

Hi,
Is the electronic ignition a CDI unit or just a pickup/sensor type? If it's a CDI type, the extra energy supplied to the coil could be too much for the ignition coil.
Have you had a look at the coil? There could be a break down in insulation when the coil gets hot. It can be checked with an in line spark tester (like this one http://www.frost.co.uk/item_Detail.asp? ... t=Ignition). This can be used to observe the spark whilst the engine is running.

David,
London,UK

[Phil69]

Thanks for your replies guys.
Manuel,
I've checked that the tank can breath OK. The choke moves freely. I haven't been able to check if the (BING) carb is set up as well as could be, but when it is running it seems to run well. Ran it today no problems ....just you can't trust over a few miles! Where to get spares (particularly electric items - which I'm beginning to suspect more and more) will be very handy.
Many thanks Phil.

Dave,
Thanks again - I'll have a look at the site later tonight.

David,
the coil has been changed with no effect on it's good running a varied amount of miles and then sudden stop. The electronic ignition is hard to describe but it's basically a solid block at the end of the alternator which contains a pick up and transistor all in one lump which detcts a lug on the end of the crankshaft. So it's probably not a CDI type - but I'm no expert. I think using a spark detctor while the engine is running and then waiting for the failure to occur may be a way forward - so I can see what's happening - eleminating things (or not) is the name of the game!
Many thanks,
Phil.

[Old Dog]

As you have changed the plug and the coil, have you changed the HT lead and cap?

As I have mentioned elsewhere the MZ-b system is the business.

Check the earth points , one under the seat and the other in the headlight shell.

[DAVID THOMPSON]

english english = earth points = the ground lug to the rest of us
dave
sort of like in the usa its parts in the uk its spares

dave
all in fun and to make us all better readers of English

[Old Dog]

Thanks Dave, but the thing is you American don't use good English. There isn't something called English English, that's just English, what you guys speak is American-English which is some sort of derivative.

Cheers and good luck with learning the language

[DAVID THOMPSON]

i have a ham radio license and some friday and sat nights i get a good lesson trying to sort out what the mate on the other
side of the pond is saying ........

20 meter rtty and psk31 and some times 160 meters ssb
dave wd8cyv

[Phil69]

Hi, hey - ground lug/earth point - it's all the same to me, I got it. Of course me speaking English english, earth piont was what I'd have written...
Looking at it, crusty attachments to metal work is a good idea to check. Although because the fault is intermittant - once all these places are cleaned up - I then have this heart in mouth ride around the block (several times) before I can declare it fixed (or not) - it's not called a 301 Saxon 'Fun' for nothing!
Oh, and HT lead and cap is replaced.
Cheers,
Phil.