ETZ 251 mis-firing after 40 minutes riding.

[Blurredman]

Yes it is an aftermarket cdi unit

do you know if ac or dc powered,usualy ac ones are larger than dc powered units iirc and run on a high voltage from stator,could be worth checking ac output from the off then when mis-fire happens

The CDI is powered from the battery directly so is DC.

Voltage doesn't drop when bike stalls and lights and ignition continue to stay on.

[Blurredman]

Interesting development chaps. Today I decided to double chech wiring, clean contacts etc. But before I did anything I turned the main beam on the switch but the bulb didn't light. It seems there was contact issues between bulb contacts and holder, which I have reinforced. I al replaced the fuse box with new one and cleaned terminals.

I started up the bike and successfully went up and down the road with lights and indicator going. No stalling when coming to a stop.

I understand why if a dodgy connection to the bulb could cause extra resistence because the light switch is also the ignition switch but Question:- if it was the bulb connection, why would it stall even when the lights weren't turned on???

[Blurredman]

Update:

Positive I had resolved the issue after a quick test, I went for a longer ride and it was unsuccessful.

It was running so smooth on the quick run but misfired and stalled at every juction on the longer run around town. Its not to do with lack of juice..


Things checked or changed so far:

Spark plug,
Coil,
Regulator,
Diode plate,
Fuse box,
Replacement wires and connections,
Electronic ignition,
New battery,

[DAVID THOMPSON]

AIR LEAKS IN INTAKE OR EXHAUST AFTER IT WARMS UP
head leak after warm up
2 smokers can be a pain some times
dave

[Blurredman]

Right.

Well I had indication that the newer reproduction coils are crap, so I put on the original, but I checked for air leaks. There was a slight air leak on the intake.

The fact of the matter is that the bike did the initial 'apparent coil overheat indicator' when doing 60mph down the motorway, which I think was really a slight soft seize occuring.

I put the old coil on and have been riding around on the bike for a while and there seems not to be any issues with stalling, nor electrical loss nor other symptons of a poorly running bike..


Thanks David!

[Blurredman]

Just a little update on this. As my above solution was incorrect!


Turns out that the air leak didn't case this issue. It was still the coil, and the bike continued to break down. I have currently got another spare coil on it and so far (fingers crossed it is working), however I am not jinxing myself this time. I will give it a week before I consider this issue resolved, but likely the problem was the coil (it was very warm!).

[DAVID THOMPSON]

use bmw 1970 to 77 /5 6 or 7 coil with a resistor there 6 volt running 2 in series in the BMW application

in 40 years i have never had a bad one
have even ran them in my cars
dave