dlogreen
Well-known Member
Guys, I had to take a step back and think about the issues pods present and how the bike responds..... this is what I have just figured out and is running amazingly with cheap pods, aftermarket secondaries, and accidentally acquired needs!
To refresh, i have two other threads... a build and troubleshooting. With lots of input from PJ and a handful of others, I started realizing I was headed the wrong direction. I have a custom 2-int-1 shorty exhaust that was struggling to idle, fouling every plug, popping after half throttle, and dying on me.
I have tried 38 idle fuel jets because I was 2.5 turns out on my mixture screws, which solved off throttle response and idling lean, but very rich once I got off the idle circuit. I shimmed needles earlier with a stock exhaust and pods, but got some bogging, so i knew it needed to go the other way.....but these don't adjust to be lower. so i thought i needed new needles or to carefully grind off a little material from the stock ones.... but that was a scary idea.
I ordered new needles, but in the meantime, I was about to change my carb diaphragms and the Ebay kit arrived with all the wrong parts and sizes. They refunded me and said to keep it. Hence my experimentation. Knowing the needle profile was allowing too much fuel as is, I figured a fatter needle would help meter that until i needed more fuel for real. The crap kit included needles of identical length and seat and diameter but with a less aggressive taper. I figured what the hell..... put em in. While I was in the top fo the carb I remembered an old post where somebody had the air jets mixed up, and that the 85 air jet goes in the pilot circuit, while the 50 goes in the secondary main circuit. Needing the bike to be richer at idle thanks to pods and more open exhaust and LEANER off needle and WOT, I swapped the 50 and 85. easily reversible.
Lastly, I raised the height of my float a half mm to further lean out the fuel mix as it got to pulling hard. And then tied it all back together.
On the bike, i set the mixture screws to about 5/8 -3/4 of a turn to account for 40% less air thru the air jet, so 40% less fuel in the mix down from 1.5 stock turns out. Idle screw set to about a turn in from where it starts to make the throttle move.
A few priming cranks and then boom.....started up and idled hard, like 2000, so I backed it off a slight turn, maybe 1/4 to 1/2. and revved it.... no bogging or hanging or popping. Battery was charging with revs and no smoke or pipe discoloration.
Test run around my neighborhood showed zero popping or gurgling on acceleration or deceleration or coming back to idle with any issues. I got back after it warmed up some, and brought the idle down and the mixture screws back in about 2 splines (the mixture screws have those ridges too). Took another lap, and this time it felt even better. I'm currently letting it sit and gonna go back to retry and confirm.
Current setup:
Might still fine tune with adjustable cb160 needles that are on the way, but right now... it's running better than it has since I got it in January.
To refresh, i have two other threads... a build and troubleshooting. With lots of input from PJ and a handful of others, I started realizing I was headed the wrong direction. I have a custom 2-int-1 shorty exhaust that was struggling to idle, fouling every plug, popping after half throttle, and dying on me.
I have tried 38 idle fuel jets because I was 2.5 turns out on my mixture screws, which solved off throttle response and idling lean, but very rich once I got off the idle circuit. I shimmed needles earlier with a stock exhaust and pods, but got some bogging, so i knew it needed to go the other way.....but these don't adjust to be lower. so i thought i needed new needles or to carefully grind off a little material from the stock ones.... but that was a scary idea.
I ordered new needles, but in the meantime, I was about to change my carb diaphragms and the Ebay kit arrived with all the wrong parts and sizes. They refunded me and said to keep it. Hence my experimentation. Knowing the needle profile was allowing too much fuel as is, I figured a fatter needle would help meter that until i needed more fuel for real. The crap kit included needles of identical length and seat and diameter but with a less aggressive taper. I figured what the hell..... put em in. While I was in the top fo the carb I remembered an old post where somebody had the air jets mixed up, and that the 85 air jet goes in the pilot circuit, while the 50 goes in the secondary main circuit. Needing the bike to be richer at idle thanks to pods and more open exhaust and LEANER off needle and WOT, I swapped the 50 and 85. easily reversible.
Lastly, I raised the height of my float a half mm to further lean out the fuel mix as it got to pulling hard. And then tied it all back together.
On the bike, i set the mixture screws to about 5/8 -3/4 of a turn to account for 40% less air thru the air jet, so 40% less fuel in the mix down from 1.5 stock turns out. Idle screw set to about a turn in from where it starts to make the throttle move.
A few priming cranks and then boom.....started up and idled hard, like 2000, so I backed it off a slight turn, maybe 1/4 to 1/2. and revved it.... no bogging or hanging or popping. Battery was charging with revs and no smoke or pipe discoloration.
Test run around my neighborhood showed zero popping or gurgling on acceleration or deceleration or coming back to idle with any issues. I got back after it warmed up some, and brought the idle down and the mixture screws back in about 2 splines (the mixture screws have those ridges too). Took another lap, and this time it felt even better. I'm currently letting it sit and gonna go back to retry and confirm.
Current setup:
- Custom Y merge shorty exhaust with fiberglass wrapped 8 inch louvered baffle. 1.375 header to 1.75 merge outlet for reference/you can see my other post for pics
- Stubby amazon pods: https://a.co/d/065MQy1o
- Silicone "velocity stacks": 5" 48mm ID tube cut in half attached to carb body. https://a.co/d/07jHooNe Then 5" 40mm ID tube halved and inserted into the pod and secured. https://a.co/d/01QrUeCe Then the smaller tube slid into the other tube to mate them and leave the carb air inlet unblocked
- Fuel Idle jet : 35
- Idle Air : 50
- Primary main: 68
- Primary air: 150
- Secondary main fuel: 112
- Secondary air jet: 85
- Float height : 21.5mm~
- Ebay CB350 diaphragm kit needle (fatter profile and less aggressive taper). This one: https://www.ebay.com/itm/306750981653
Might still fine tune with adjustable cb160 needles that are on the way, but right now... it's running better than it has since I got it in January.
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