searched around a bit here and didn't find too much definitive information, so I figured I'd start a new thread.
I have two 17mm bing carbs, each one has some slight differences. I wanted to use one on a kitted e50, but I think their atomizers are designed for very different applications.
1/17/36 - came off an old (late 50s early 60s) Sears Allstate 3 speed scooter
1/17/89 - came off a late 60s Sears Sabre 4 speed small motorcycle
the 36 has a 2217 atomizer (came with 84 jet)
the 89 has a 2447A atomizer (came with 90 jet)
the 2217 has one hole up near the threads
the 2447A has 4 holes up near the threads
Both atomizers are 31mm long, compared to my 217 and 222 atomizers from smaller Bings, which are 29.5mm long.
Using either of the 4 digit atomizers leaves me with some super funky bogging issues depending on how much I open the throttle, and the 222 atomizer makes me idle very high and seem to run rich beyond half throttle. I haven't fiddled with the 217 yet, nor have I tried different needle positions just yet, and I also have a wide range of jets at my disposal...
But my main question is what atomizer is considered the best option for running these 17 bings on a single speed e50?
I've seen Ken Roff mention that a 215 should work well, but I'm wondering if there's any further discussion or understanding as to why, and maybe what purpose each different atomizer has.
When I was tuning my friend's PHBG, the Dellorto Tuning Guide mentions different holes in the diffuser tube for 2 stroke vs 4 stroke applications... it talks about how the pressure influences the fuel pickup or something like that.
All the atomizers I've seen in smaller Bings so far have had no holes. These two 17mm atomizers came from bikes that had multiple gears, which leads me to wonder if they typically operate at lower RPMs and maybe the holes have something to do with lower-speed airflow? If there are holes in the atomizer, wouldnt that allow air to bypass the jet? The tube that the atomizer sits in also has a hole in it, so there is definitely a clear path for air to be pulled in...
If I use a 215 atomizer, or any other size, will it matter that the overall length may be different? The bowl seems to still be deep enough to keep the jet submerged...
This site seems to have some info about the different carb variations, but nothing useful other than original configuration/application
http://www.greiner-oldtimerteile.de/vergaser-ersatzteile/bing-vergaserteile/gruppe-742-bing-44-duesen/browse.php?sid=669201342357909&pos=c1729
[attachment 152138 atom1.jpg]
[attachment 152139 atom2.jpg]
I have two 17mm bing carbs, each one has some slight differences. I wanted to use one on a kitted e50, but I think their atomizers are designed for very different applications.
1/17/36 - came off an old (late 50s early 60s) Sears Allstate 3 speed scooter
1/17/89 - came off a late 60s Sears Sabre 4 speed small motorcycle
the 36 has a 2217 atomizer (came with 84 jet)
the 89 has a 2447A atomizer (came with 90 jet)
the 2217 has one hole up near the threads
the 2447A has 4 holes up near the threads
Both atomizers are 31mm long, compared to my 217 and 222 atomizers from smaller Bings, which are 29.5mm long.
Using either of the 4 digit atomizers leaves me with some super funky bogging issues depending on how much I open the throttle, and the 222 atomizer makes me idle very high and seem to run rich beyond half throttle. I haven't fiddled with the 217 yet, nor have I tried different needle positions just yet, and I also have a wide range of jets at my disposal...
But my main question is what atomizer is considered the best option for running these 17 bings on a single speed e50?
I've seen Ken Roff mention that a 215 should work well, but I'm wondering if there's any further discussion or understanding as to why, and maybe what purpose each different atomizer has.
When I was tuning my friend's PHBG, the Dellorto Tuning Guide mentions different holes in the diffuser tube for 2 stroke vs 4 stroke applications... it talks about how the pressure influences the fuel pickup or something like that.
All the atomizers I've seen in smaller Bings so far have had no holes. These two 17mm atomizers came from bikes that had multiple gears, which leads me to wonder if they typically operate at lower RPMs and maybe the holes have something to do with lower-speed airflow? If there are holes in the atomizer, wouldnt that allow air to bypass the jet? The tube that the atomizer sits in also has a hole in it, so there is definitely a clear path for air to be pulled in...
If I use a 215 atomizer, or any other size, will it matter that the overall length may be different? The bowl seems to still be deep enough to keep the jet submerged...
This site seems to have some info about the different carb variations, but nothing useful other than original configuration/application
http://www.greiner-oldtimerteile.de/vergaser-ersatzteile/bing-vergaserteile/gruppe-742-bing-44-duesen/browse.php?sid=669201342357909&pos=c1729
[attachment 152138 atom1.jpg]
[attachment 152139 atom2.jpg]