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.
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!
Yep, need to upjet with the bigger carb. Even with the 14mm intake.
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)
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?
Yes stock air box sucks and you could have the dreaded 212A atomizer in your carb
yeah, thanks Ken,what atomizer would you run with that set up?
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
pretty sure it has the 222, but will double check, thanks again.
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
http://www.mopedarmy.com/forums/read.php?7,2891329,2893812
http://www.mopedarmy.com/forums/read.php?7,2116363
http://www.mopedarmy.com/forums/read.php?7,2117054,2120556#msg-2120556
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
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.
^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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