Bing slide question

I have a 70cc kitted Maxi that would not idle with the 14mm Bing I was using.

Did the hole mod on the #24 slide and it worked better.

Upgraded to a new 15mm Bing and it did the same thing so I switched to the old holed slide and it worked about like the 14mm did. I have a #51 slide with a small hole drilled in the backside at an angle down to the needle. I am wondering if this might provide a better/leaner mixture than the standard 24 without mod. (edited)

Re: Bing slide question

You haven't stated the details on your jetting, atomizer etc.

Re: Bing slide question

Its a ZA50 with a 2.17 atomizer and 78 jet and 2 ring needle on 2nd from the richest and a mesh filter with a Tecno Circuit pipe and geared at 21/36

It simply would not idle before I did the hole mod on the #24 but I was a bit concerned about being too lean on down hills with throttle closed.

Just got back and it seems to run fine with a stock $51. It is a bit hard to start, maybe I need to learn a new technique but other than that it ran well.

I can hit 40 ish on the level but am hoping for a little more with a bit more tweaking.

Tom

Re: Bing slide question

Ive got an e50 but i assume the tune is close...

I was having the same issure. But ive been with the 15 clone the whole time. Ivr got the 217 atomizer used the needle that came with and slide. Modded the slide. Runs great but idle is low ive found for me 78 is making the plugs super wet and black.

Altho my idle is about 1500 and after a few minutes it gives up. But im running 76 richest clip setting 78 with leanest was rich ive not done chops yet but the 76 runs great and temps are low

Re: Bing slide question

Tom with Bings the $14 mesh air filter seems to work the best or none at all but (try down jetting) and don't play with the bore size...or...over bore the Bings as you will cause idle problems and need to change to 2.15 atomizer and start over...

Re: Bing slide question

When tuning a 15 Bing on reed motors is easy and work great but for piston port motors sometimes can be a Bitch especially at idle... It's best to try everything possible...jets, atomizers, slides, needles, clip settings, ect... before drilling slides or hacking carb bodies ect...I have tried everything but what works best for me is to put a 2.15 atomizer in it and a larger jet to compensate... run an 80, 82 or 84 jet for good mid and high rpm power. The plug chops even seem to look better than the 78/2.17 set-up.... remember this is for piston port motors only...

Re: Bing slide question

And for the 51 slide the cutout at the bottom is even worse and if you put them side by side you will see what I'm talking about here is a pic...you want the 24 slide and 2-ring needle and can be identified by the notches below the 4-clip slots on the needle...

BING slide.jpg

Re: Bing slide question

there's no reason that you should have to mod or change the components in a 15 Bing just to idle. You need to look elsewhere. Test for airleaks and make sure your starter clutch isn't engaged at idle.

Re: Bing slide question

I just completely rebuilt the engine and it still is doing it with the new 15mm/2.17/28 Bing. Added the slide with the hole and it runs better although still a bit hard to start. The #51 slide seemed to work also for some reason. It is a "too rich" issue at starting/idle. An air leak would be a too lean issue would it not?

I ordered a 2.15 slide as Bobby Selby suggested and will give that a try.

Thank you for the suggestion, these are finicky motors when it comes to carb tuning.

Re: Bing slide question

Atomizer....slide....jet...needle....jet....slide....atomizer....????

Re: Bing slide question

Probably Fred /

Tom Hale Wrote:

-------------------------------------------------------

> I just completely rebuilt the engine and it still

> is doing it with the new 15mm/2.17/28 Bing. Added

> the slide with the hole and it runs better

> although still a bit hard to start. The #51 slide

> seemed to work also for some reason. It is a "too

> rich" issue at starting/idle. An air leak would be

> a too lean issue would it not?

> I ordered a 2.15 slide as Bobby Selby suggested

> and will give that a try.

> Thank you for the suggestion, these are finicky

> motors when it comes to carb tuning.

It's only finicky because you put aftermarket kit on it, aftermarket pipe on it aftermarket 15 mm Bing (15mm never came stock) on it and piston port kits in general are very finicky to jetting compared to reed valve kits.

You think a 15 mm Bing is hard to tune don't upgrade to a 19-21 mm Dellorto phbg like some do.

Tuning a 70cc treats kit with a phbg carb made many people quit mopeds

Re: Bing slide question

The Treats order came today. Put the 2.15 and 82jet in the carb with the needle on the richest position and it started up right away. Raining for 3rd day now but tomorrow looks better so will be able to take it out for a test run.

Re: Bing slide question

E50 + Bing is the least finicky moped motor to tune ever. I work at a moped shop. We put (real OEM) 15 Bings on e50s w/ kits and pipes all day and never have to change anything but the jet. The 14 Bings always work fine too.

This isn't meant to be insulting but saying that you just completely rebuilt it only makes it way more likely that the problem is with that. Don't ignore the possibility that there is a problem with the rebuild. How exactly do you know it's a "too rich" problem at idle? Is the plug black and dry, black and wet or brown and glossed? Glossed means a timing problem. Is the plug color good but producing smoke? That would indicate a clutch side seal leak.

Re: Bing slide question

Pizza the Hut, I love that handle

No offense taken I fully understand you concern.

I have read a ton of info and asked many questions here on MA and have learned so much with all the help.

The ZA50 in question vibrated a bit when I first got it at 30-33 mph which was top speed. I decided to kit it and chose the Airsail 70cc kit and already had a Tecno Circuit pipe/mesh air filter on it. This is when I had the starting problems, plug was wet when I would pull it after not starting. I could get it started by peddling like hell and it would start slow then finally come up to speed. After starting it seemed to run fine but as I approached idle it would want to quit again. The 14mm Bing had a #24 slide and needle was on the leanest position but still was way too rich for idle. (As a note I just realized I have 3 needles, and one is a 1 ring and the others are 2 ring. I may have had the 1 ring in at the time, not sure now.)

After the rebuild is when the vibration became much more noticeable as it was able to rev a bit higher up around 8000 on a tach. I shimmed the tranny using plastigauge to well within specs and it still it was vibrating way too much. I then rebuilt the motor with much help from many here especially "Ken". Used a 300 mile crank I bought from him, all new crank bearings, seals etc. Was able to get the crank float to about .002. After assembly the motor ran MUCH smoother, I was pleased. Installed a new Bing 15mm carb/2.17/78 and had the same rich starting issues. Put the old #24 slide with the hole mod and it started fine. As I think about it now I may have been using the single notch needle which MAY have been the culprit all along.

After I finish my morning cup of coffee I am going out to the garage and reconfigure the 15 Bing to 2.17/78 and be sure its a 2 ring needle and see how that goes.

Still have compression/squish issues that I am working on.

Tom

Re: Bing slide question

Probably Fred /

Pizza the Hutt Wrote:

-------------------------------------------------------

> E50 + Bing is the least finicky moped motor to

> tune ever. I work at a moped shop. We put (real

> OEM) 15 Bings on e50s w/ kits and pipes all day

> and never have to change anything but the jet. The

> 14 Bings always work fine too.

>

> This isn't meant to be insulting but saying that

> you just completely rebuilt it only makes it way

> more likely that the problem is with that. Don't

> ignore the possibility that there is a problem

> with the rebuild. How exactly do you know it's a

> "too rich" problem at idle? Is the plug black and

> dry, black and wet or brown and glossed? Glossed

> means a timing problem. Is the plug color good but

> producing smoke? That would indicate a clutch side

> seal leak.

Ya in Tom's defense a za50 is harder to tune then a e50 do to increased crank case volume, oil holes to 2 orifices/two bearings sets and longer intake, (also has a goofy right side steeped transfer)

Stock it never came with bigger than a 12 mm bing carburetor nor did it ever have any atomizer/needle jet other then the 212a. A Za50 needs to have good low end jetting for with extra gears, shafts, clutches and 9 (yikes 9 bearings) bearings it takes a bit more umph for a good launch.

Za50 is about the best auto 2 speed moped (and euro dirt bike) engine made due to its reliabilit, tunability/able to handle high hp.

Re: Bing slide question

I spent most of the day tuning.

Now that I am setup with a low bench for the Pooches, as my wife calls them, and the right tools moped life is good.

Changed atomizers, needles and jets and different heads and gaskets for compression and squish. Made at least 8 runs and finally think I have it about as good as I like for now. It shifts into 2nd at 27mph and tops out at 40 and 4strokes when throttling down but with very smooth throttle response. The max head temp I saw was 325 BUT that was at 60deg and at times light mist so was kinda water cooled. I did discover something. I have only one 2 ring needle from a used bing I bought but did not use. The new Bing came with a 1 ring needle and that was apparently the problem with both the 14mm and 15mm not idling worth a damn. It amazing how fast one can get changing stuff for tuning. I timed myself, new atomizer and jet, needle reset off and on in under 6 min. No record for sure but very satisfying.

I am far from done but it was a good "Pooch" day thanks everyone that helped out.

Tom

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