ETZ250 seemingly randomly stalls

[Blurredman]

I've encountered this issue for the past few months, but then I got my CX500 back on the road and let myself forget about the MZ for a while... Why do bikes suddenly create a new problem after riding perfectly for hundreds, maybe thousands of miles!?? Anyway, insurance ran out on the MZ, then I rode to Serbia on my Honda. Come back and I would like to ride my MZ again.


Obviously the same problem is there. I believe it's fuel related, but on each inspection of the carburettor it all seems okay. Basically:


Randomly stalls, typically at lower speeds, but sometimes might stall after riding for quite some distance without any stopping. It might bog before it stalls, and backfire too, but I'm unsure if it's lack of fuel or too much. I am thinking too little because if I leave it even for 1 second and kick it back into life it will start and ride on like nowt happened.

The distance between stalls seems to have no correlation. I went out for a 30 mile ride yesterday and it initially stalled just as I got to a junction, then 10 miles after (doing 40mph and 30mph), it stalls at a roundabout after doing 50 for a mile, then it doesn't stall for another 18 miles (doing high speed and slow speed) until just before I get home. It stalls on both reserve and main on the tap. There is no crap in the carburettor or filter catches, fuel comes out of the tap at a good pace.

[Blurredman]

I have found out that the float heights are woefully out in both closed and open position.

Closed was coming out at around 20 (stead of 27), and open was about 25 instead of 34! Why I had set it so wrongly in the past I have absolutely no idea, i'm normally meticulous about float heights. I think I might have set them so to solve an issue which may or may not have been connected.
I have little memory of my actions prior. We all mess with our MZ's too often to remember why, right?


I will try it out soon and report back.

[Blurredman]

Okay well.


The bike stalled twice on the way to work this morning. Once when at the bottom of a long hill, where I had obviously not used throttle.

The other was after a 50/55mph run for a few miles, without issues then as the speed limit changed to 30, and I changed accordingly the bike slowly ground to a halt. This particular stall felt more like a switch. I am thinking towards electrical now that the float heights are correct and taking into account the type of loss of power.


I have to note also that the bike doesn't really idle well. A problem I have encountered before where the idle screw does not compensate for the fact that the idle will gradually decline over a period of a minute or two until it fails to cycle itself at all.


I will check connections now. But I do have a spare carburettor on another MZ which I may try to rule out fuelling.

[DAVID THOMPSON]

I have been having problems with bad fuel.
There seems to be times that some of it just does not want to burn
My little car with the lawn mower motor throws a fit an stalls on it as well
As my new kawsaki powered mower
Dave

[Blurredman]

Well, i'm getting somewhere. The problem looks to be carburettor related.

I swapped mine with my brother's.

No stalls. It's running a little richer than usual but perfectly usable. My brother's carburettor however is a Taiwanese re-production of the same 30N2 model that replaced his and it is the same as mine. I just wonder whether it might be best first to work out whether it's the actual carburettor body or something simple like the slide, or jet. I will do some swapping and switching when next I have time. The plan being to put all jets, and slide into my original carburettor's body. We'll see what the outcome is..

[Blurredman]

Just an update. Not many people seem to post these days?



The problem seems completely fixed. After figuring out it from swapping with my brther's carburettor that it was a fuelling issue, I took my carburettor (for the millionth time), and cleaned it as thoroughly as I could, with compressed air and solvents down every channel I could see, definitely making sure there was in no doubt any crap anywhere.


I went out for a ride tonight, no stalls. Idle circuit or low speed must have been clogged somewhere, although I saw nothing come out it didn't mean nothing was not in it. It was actually really pleasurable, as it always is when you are just riding for the fun of it without a deadline to be a certain place by and without the bike acting up. It is running rich at the minute but I can easily tunnel that back down to perfection.


Finally. This issue has been annoying me for a few months now.

[therealche]

Thanks for coming back! Carb problems can be a real pain to sort out.
New years resolution , to come here more often!