Bing Jetting - 15mm/14mm

Hey guys, quick question. I just got a new 15mm bing, but kept my 14mm intake until i can bore it, or get a 15mm intake. Do I need to rejet? I had the 14mm bing on before with a 72. I know people say it doesn't make a different if you have a 15mm bing if you have a 14mm intake, but does that mean no rejetting? Or should I go up a couple? Thanks.

Re: Bing Jetting - 15mm/14mm

Trevor Fladwood /

I run a 15 mm bing with a case-matched 70cc kit, circuit pipe and use an 82 and it is right on. It always helps to start rich and go down from there.. less likely to break anything that way!

Re: Bing Jetting - 15mm/14mm

Yep, need to upjet with the bigger carb. Even with the 14mm intake.

Re: Bing Jetting - 15mm/14mm

And that's with the 14mm intake?

Or you run an 82 with your setup along with a 15mm intake?

I have it on a 76 right now with the richest needle setting. I was at a 72 with the 14/14, but i didn't upjet too far because i added the Hi comp head (correct me if im wrong, but i figured you would downjet with the added compression) Setup below

Case matched and slightly ported 70cc Kstar

Hi Comp Head

Tecno Circuit

Hi Flow filter

15mm bing/14mm intake (edited)

Re: Bing Jetting - 15mm/14mm

I don'get how you guys run such big jets. My set up is; 14bing ,techno circuit, 45mm airsal, and it 4strokes with anything bigger than a 66.....hmmm you think it could be the stock air box?

Re: Bing Jetting - 15mm/14mm

Overpriced Parts /

Yes stock air box sucks and you could have the dreaded 212A atomizer in your carb

Re: Bing Jetting - 15mm/14mm

yeah, thanks Ken,what atomizer would you run with that set up?

Re: Bing Jetting - 15mm/14mm

Overpriced Parts /

14mm bings come with #222 atomizers But many people put bastard parts in them.

With 14 mm bing, a metal mesh filter, 70 cc kit and a techno circuit pipe my jetting always seems to come up at # 72 jet

Re: Bing Jetting - 15mm/14mm

pretty sure it has the 222, but will double check, thanks again.

Re: Bing Jetting - 15mm/14mm

#CrazyWayne™ rocks. #CrazyWayne /

2.17 and 2.19 will be leaner.

Get the two and one ring needle's.

Most 14/15mm bing's with piston port 65cc/70cc kits tune in close with a 2.17 atomizer, two ring needle, #72 jet.

More Bing info

https://www.mopedarmy.com/forums/read.php?7,2891329,2893812

https://www.mopedarmy.com/forums/read.php?7,2116363

https://www.mopedarmy.com/forums/read.php?7,2117054,2120556#msg-2120556

Re: Bing Jetting - 15mm/14mm

I run a 78 on a 15 bing on 50cc

but ye you'll have to upjet, the vac is less in a bigger carb so needs a bigger jet to pull nuf fuel up

Re: Bing Jetting - 15mm/14mm

Trevor Fladwood /

Yep.. mine was with the 15mm intake. My setup is same as yours except I didn't port my kit, and I have the 15mm intake, and 82 is right on for me.

Re: Bing Jetting - 15mm/14mm

^agreed to the fullest every k star ive built with a bing has loved a 72 jet its my magic number. But im 18 feet above sea level. I always start with a 72 on a 14 or 15 bing and k star. Perfecto

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