ZA50 dies on idle. (No leaks!!!)

Hello good peoples!

A few weeks ago I posted about a similar issue and I discovered an air leak (of course). This is similar, but not the same, I think.

Problem: Must idle super high to prevent engine from dying. Bogs at low end.

I've sprayed the whole thing down with carb cleaner a few times and have found no leaks!

I can start the moped up just fine, could be maybe a little better.

I have to idle very high in order to prevent it from dying out. I've screwed the idle all the way in, and I have to hold the throttle open a bit til it actually pulls me in effort not to die out. Overall it rips around, but on the low end it bogs if i don't pedal and dies at idle.

I've played around with some jets and needle position. Even tried taping off the filter. Can't quite get it right.

Sometimes I can get it to idle pretty well on kickstand, but when I put my weight on it. It dies...

What should I do? Does my setup seem proper? I don't want to jump the gun and do a LIL BUDDY hole if I don't have to.

I want to ask you guys before I start ordering new jets/filters/atomizers/gasket etc...

My setup:

ZA50, Treats kit, flipped clutch, 20x36 gearing

Proma circuit pipe

14mm intake and Bing carb (I think 14mm)

2.20 atomizer

76 jet

2nd from bottom position on needle

Standard shit quality hi-flow mesh airfilter



Re: ZA50 dies on idle. (No leaks!!!)


It does sound like I'm running too rich, but putting a can over the air filter I found actually helped the idle.

So I'm bloody confused.

The symptoms keep changing on me. Or don't add up!

Overall, if somebody sees a problem in my setup re: jets/atomizer then please tell me what to try :D (edited)

Re: ZA50 dies on idle. (No leaks!!!)

I just got my E50 idling again after two years of struggling with the problem you have. Pretty sure I fixed the issue by making sure my carb was assembled correctly. Made sure the needle top clip (washer thing between needle and spring) was seated correctly. Worth a shot to check if everything's good in your carb...

Re: ZA50 dies on idle. (No leaks!!!)

Overpriced Parts /

Use a 222 atomizer, #72 jet, # 24 slide, single ring needle if double don't ring work good, needle clip 2nd or third but anywhere that worjs good. treats sells the single ring needle at least it looks like the one subtle ring above the clip grooves in the picture but I'm not sure.

I did over 2 dozen 70 cc 14 mm bing set ups with that jetting but with tecno circuit pipe if you have a real big pipe then maybe a 74 jet.

If you still can't idle then you can do my hole trick putting a small hole (3/32)ish each side high on the #24 slide just so air flows at idle but covered when the throttle is cracked but try the jetting I use first.

Re: ZA50 dies on idle. (No leaks!!!)

Overpriced Parts /

Yes make sure the choke is clipped in to the shaft too

Re: ZA50 dies on idle. (No leaks!!!)

user name,

I've cleaned/reassembled the carb a few times and it all seems proper. But heck, I'll check again! Thank you.

Ken, the choke is clipped in.

I'll do everything you just said and get the right parts for the job!

Time to put my order in.

I really really appreciate the help here.


Re: ZA50 dies on idle. (No leaks!!!)

Also I said I was using the wrong pipe.

I'm actually using the tecno circuit pipe. So lucky me that you've done quite a lot of them!

Thank you

Re: ZA50 dies on idle. (No leaks!!!)

I guess the next question is, who sells #24 slides?

Re: ZA50 dies on idle. (No leaks!!!)

Overpriced Parts /

I'm working on one now well I got all the parts, engine and bike

What im gonna do when the garage is warmer is

Dmp 70 cc kit, hi comp head modded for better squish

Za50 timed 16 degrees btdc

Flipped 2nd gear clutch

14 mm bing (72 jet) or 15mm bing (78jet)(not sure which carb I'm using yet yet )

Metal mesh filter

Tall 14mm intake bored to 15mm and matched to square port

Tecno circuit pipe

20x35 gears

It's just too cold in the garage and I got a broke ass knee that is even worse when its cold

Re: ZA50 dies on idle. (No leaks!!!)


Nice setup.

I got to learn some tuning!

I'm in Canada and today was the first day I didn't need a heater and a jacket when wrenching.

Re: ZA50 dies on idle. (No leaks!!!)


what spark plug do you use on that setup?

Re: ZA50 dies on idle. (No leaks!!!)

What ignition system are you using? The ZA50 has a problem with too little rotational mass. So for example if you are using the HPI internal rotor its too light to keep the engine spinning.

Re: ZA50 dies on idle. (No leaks!!!)

Overpriced Parts /

Stock Points, #8 plug

Re: ZA50 dies on idle. (No leaks!!!)

Thanks Ken. I'm the same.

Stock points Nick.

Also, I have my atomizer and some jets in mail. Hope this will help me!

Thank you,


Re: ZA50 dies on idle. (No leaks!!!)

Carb tuning is tough to do over the internet. It could also be a lot of other things. Was this a complete engine rebuild? Could it be a bad seal or case gasket? Bing carbs have a built in leak on the top where the carb meets the intake, you need an O-ring to fix that one. I would suggest (if you can) finding someone local to help.

Re: ZA50 dies on idle. (No leaks!!!)

I don't believe it was a rebuild. I just got the bike from another fella who did these mods, but he didn't mention opening it up.

I ordered some new gaskets with my jets and atomizer. So if they don't fix the problem I'll take 'er apart and swap some gaskets.

Problem is, I really like driving my moped! So given that I can't idle at stop signs, I end up ripping right through them :S No good....

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