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Post by repherence2 on May 18, 2022 22:10:31 GMT -5
Venturi divider? Available for purchase? Anyhow I’ve been chomping at the bit to get one of these smart carbs I can’t wait to see if it fares any better than the electron carbs.
i cut my own from 1/16 inch aluminum
a prototype that i made and tried for a little bit. i bought the clear plastic from the craft store. i think it is polyethylene.
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Post by pete130 on May 19, 2022 23:16:36 GMT -5
Venturi divider? Available for purchase? Anyhow I’ve been chomping at the bit to get one of these smart carbs I can’t wait to see if it fares any better than the electron carbs.
i cut my own from 1/16 inch aluminum
a prototype that i made and tried for a little bit. i bought the clear plastic from the craft store. i think it is polyethylene.
Nice job, I was thinking I would have to make one, your pic are great, now I have an idea what to do, im guessing you have them so they slide Into each other to lock in. |
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Post by pete130 on May 19, 2022 23:17:39 GMT -5
Venturi divider? Available for purchase? Anyhow I’ve been chomping at the bit to get one of these smart carbs I can’t wait to see if it fares any better than the electron carbs.
i cut my own from 1/16 inch aluminum
a prototype that i made and tried for a little bit. i bought the clear plastic from the craft store. i think it is polyethylene.
I just blew the picture up and see its plastics yes, |
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Post by repherence2 on May 20, 2022 20:51:24 GMT -5
Nice job, I was thinking I would have to make one, your pic are great, now I have an idea what to do, im guessing you have them so they slide Into each other to lock in.
correct on them interlocking into each other. cut a center line slit equal to the thickness of the material (plastic) but only 1/2 the length of the divider and on opposite. one has a slit on the carb opening side and the second one has the slit on the slide side. the clear poly sheet was so much easier to work with versus the 1/16" aluminum. on my second prototype, i used a coping saw to cut notches/grooves on each side of the carb mouth so that i could seat the plate in. cut the plate slightly over sized, beveled the edges, and used that to seat the divider into the carb mouth. the poly plastic version was way easier to construct. razor blade to cut the plastic and cyanoacrylate (super glue) to mate the 2 dividers together.
For Your Information, the vertical divider may have an adverse affect on the fuel dispersion as the needle/slide rises and the fuel comes up from the main jet, but i cannot say for sure. while in a main jet tuning frenzy, i pulled the double divider and tune the carb. horizontal divider is good enough. but if you like try the vertical divider as well, that is up to you. i think i might make another prototype in which the vertical divider is not flushed up to the slide but spaced 1/8"-1/4" from the slide. currently i am running a different aluminum horizontal divider that i hastily fabbed up. there is a gap between the aft edge of the divider and the flat face of the slide of about 1/16"-3/32"". i think it is having an effect on the the way it responds from 1/4 to 1/2 throttle. the first divider i made was crafted so that it was flush with face of the flat slide and the response on the low throttle was better.
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Post by 65grendel on May 21, 2022 21:32:01 GMT -5
I’m not cpu savvy but this seems like the type of thing a 3D printer could make and test different orientations? Possibly sell them?
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Post by hippo008 on Jun 3, 2022 18:41:46 GMT -5
The smartcarb arrived today and it's already fantastic. Shipping and packaging details It came in an outer box from ScooterSwapShop and then a smaller inner box from Technology Elevated. SSS opened the inner box to verify contents. It was shipped well. Not only was the carb in two boxes it was also suspended in a sort of cardboard cradle preventing it from rolling around. It arrived in perfect condition. SSS also ships with full insurance so in the event your carb is damaged you won't be left with extra costs or a broken carb.  Inside the box there was a quickstart guide, an overview on the smartcarb and Technology Elevated as well as a tuning manual. I read the tuning manual front to back before I started messing around with the carb. I HIGHLY recommend anyone who purchase the carb do the same. The tuning manual contains some vital information about first time setup, basic usage instructions as well as complete instructions on installation, adjustment and tuning. Sone important details I noticed. Whenever you run the bowl empty you must fill the carb with fuel while the choke is on. When you first install the carb it is recommended to NOT change any settings before your initial adjustment phase (more on this later) First Impressions
You are getting a very high quality product. Every inch of the body, cap, knobs and internals are all machined aluminum. When compared to a Polini 26 PWK the SC2 weighes substantially more. The body of the carb feels thick and sturdy, absolutely nothing feels cheap or improperly made. The fuel in port is on the opposite side I am used to, sitting adjacent to the idle speed adjustment. Stainless Allen key bolts were used anywhere possible and the anodizing feels smooth and professional. On a scale of 1 to 10 with 10 being a very high end product this is an easy and resounding 10 of 10.
Installation Installation was very simple. The smartcarb installs the same way any other PWK type carb would install. One small difference is the slide. The slide is weird. Is essentially a block. Its not made of aluminum, its made of another metal. Any PWK compatible throttle cable will work with this carb and side. Installing the cable was the same as any other PWK. The lug on the bottom of the throttle cable slides into a slot adjacent to the spring and locks in place with spring tension on the slide. It should be noted that the SC2 has a larger body than a similar PWK style carb. My Polini PWK 24 (same size body as a 28MM) easily cleared my TWH brand dustshield. I needed to remove the dust shield to allow the SC2 to fit properly. It's not a massive difference in size but it's enough that it may cause unexpected clearance issues.  First Start and Run
This is where this product goes from quite good to WOW. This carb was ordered and setup for a 90cc AF18 Honda motor with flowed cases halves. That motor isn't ready yet so I decided to put it on my Polini Corsa + C16 AF18 Honda motor. This is a fundamentally different setup. Less displacement and a smaller stroke but much higher RPM target than a 90cc stroker motor. The corsa C16 setup spins out to 13,000RPM WOT and runs a 24mm Polini PWK. By all standards the SC2 shouldn't run well on this motor. The SC2 did not come set from the factory for this engine setup.
I primed the fuel bowl with the choke on as stated in the instructions. I simply turned off the key and gave the scooter a few kicks to push fuel into the fuel bowl. I let it sit for a few minutes in case it wasn't totally full. I turned on the key and after 1 kick, choke off, totally cold it started right up. Idle RPM is lower than I'm used to at only 1450~RPM but it sounds exceptionally clean and stable. I let the bike warm up to about 130° CHT before I gave it any gas.
After the warmup I strapped on my helmet and took it for a short ride up and down my road. Unfortunately it's raining today so I couldn't go for a full ride and test. The scooter ran flawlessly. No overheating, no bogging, no lean condition symptoms, nothing. It spins all the way out to its expected 13,000RPM absolutely no problems. The throttle is incredibly tight, precise and crisp. A 28MM PWK on this Corsa C16 setup normally has a large dead spot on the needle. Right around 50% throttle you lose throttle response, torque and speed. It tends to come back once you get past 3/4 throttle or so. That is not the case with this 28mm SC2. It was screaming at every throttle position and asking for more. There were no dead spots or trouble areas, just super clean and crisp throttle from idle all the way up to WOT.
After I got back to my yard I stopped and checked my side cover for fuel spillage. Dios have a vacuum pulse fuel pump that will sometimes push fuel right past a float bowl and out a vent tube especially at high RPM. I looked around the carb, the intake as well as the bowl and not a single drip of gas. Totally bone dry and clean.
This is looking very promising. It seems like this carburetor is already living up to expectations. |
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Post by 90GTVert on Jun 5, 2022 6:50:47 GMT -5
Nice write up and great first test results. Because I've been bitten by a fancy carb before, be careful with part throttle. My Lectron seemed very rideable out of the box, but once I started really riding and trying to use mid throttle it started melting pistons. Clean sounding and crisp responding 2Ts can be lean at part throttle. If you're lucky, CHT will rise quickly enough to let you know something's up, but it may not. EGT has been so much better for seeing where the tune is at various throttle positions for me. You may hear spark knock as it gets hot, and maybe not. You probably already know all of this, and I hope this is not an issue for your setup, but just a friendly reminder to keep your eyes and ears open for a bit.
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Post by drc174 on Jun 6, 2022 11:38:51 GMT -5
Nice write up and absolutely sums up the SC2 experience!
I have been using/selling SC2's for various application, mostly LF Vespas and the results are always chill inducing. Glad the 50cc market is picking up. the Honda AF motor is PERFECT for it too as it loves big carbs.
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Post by hippo008 on Jun 9, 2022 12:00:05 GMT -5
Tuning Updates & Customer Service Experience I put together the 90cc AF18E motor the smartcarb was built for. As a short reminder its a 50mm bore and 44mm stroke. It has flowed cases, a big valve intake and a NCY Dio pipe. I expect this setup to make more torque and about 10HP at 7000~ or so RPM, but I havent Dyno tested it or anything. I installed the smartcarb as normal. I used the recommended settings, 87 turns from rich on the clicker and .788" out on the idle speed adjustment screw. The scooter wouldnt start without giving it gas and wouldnt idle. It is idling very rich, smoking like crazy and very low RPM. I wasnt able to get the scooter to idle for more than a moment, it would die almost immediately. Clearly some adjustment is needed. I figured this was a great time to call the Smartcarb people and ask for advice as part of the SmartCarb package is tuning help from the SmartCarb engineers. I called and got through very quickly. I was greeted immediately by a person and not a machine. I was speaking with one of the product engineers and founders of the company. He asked for all sorts of information about the carb and its application. Once I mentioned it was for a 90cc Honda Dio motor he asked me for lots of additional information. Mounting, intake types, reed style, intake location and more. He explained over the phone that the Scooter market is very new to them and that within the scooter market there are very few Honda tuners. I got a good chuckle out of that, there are dozens of us Honda tuners  . The tech told me that they have limited experience tuning these motors and hes very happy to help but it wont be as easy as something like a GasGas 300 or KTM 300XC which they have lots of experience tuning. I was given specific instructions on what to do and how to do it then to report back with my findings. He assured me with my engine and the needle provided I should have a great running scooter once we get the low end dialed in. He suggested I lean out the engine two clicks at a time until I reach a clean and stable idle, record my clicker setting and report back with my findings. He also noted that about 30 clicks of the metering rod is equivalent to about 1 needle clip position in a PWK. Limitations of the Smartcarb After some general use I have found two major drawbacks of the SmartCarb system. The first one is WOT tuning capability. While it seems the metering rod SmartCarb supplies works well 90% of the time theres a chance it wont work well out of the box. With a PWK type carb you can pop in another cheap mainjet and try again for about $3 and 30 minutes of effort. With SmartCarb if you are having WOT issues then you will need another metering rod all together, something like $70 each and the time to install the new metering rod. The second major drawback is mounting limitations. The SC2 is highly sensitive to certain types of vibrations. Its very important that the carb is not touching any hard or metal surfaces when mounted. In my case I had very slight contact with my CVT cover that needed to be ground down. In most scooter applications I dont see space being a major issue but its something to keep in mind. I have run PWK and Dellorto carbs in all sorts of funky positions without much issue, I am not sure that can be said about the SmartCarb. I will continue to update this thread with tuning updates. |
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Post by drc174 on Jun 9, 2022 19:34:55 GMT -5
Sorry to correct you there. The metering rods are 40$ with me and I take them back at full price as they are a non-wear item. (So does SC)
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Post by hippo008 on Jun 9, 2022 20:28:41 GMT -5
Sorry to correct you there. The metering rods are 40$ with me and I take them back at full price as they are a non-wear item. (So does SC) This is wonderful news! I was getting my prices off SCP scooter shop in Europe, I was seeing something like €52 a pop + shipping. After a quick search I wasn't able to find somebody in America selling the metering rods through a webshop like SCP. At $40 a pop that's still not cheap but that's essentially half the price, even better considering TE will take them back no charge if they don't pan out. |
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Post by pete130 on Jun 15, 2022 3:37:25 GMT -5
i cut my own from 1/16 inch aluminum
a prototype that i made and tried for a little bit. i bought the clear plastic from the craft store. i think it is polyethylene.
I just blew the picture up and see its plastics yes, Thanks for the link very useful im always looking for new things I don't know about appropriated |
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Post by pete130 on Jun 15, 2022 3:42:36 GMT -5
Nice job, I was thinking I would have to make one, your pic are great, now I have an idea what to do, im guessing you have them so they slide Into each other to lock in.
correct on them interlocking into each other. cut a center line slit equal to the thickness of the material (plastic) but only 1/2 the length of the divider and on opposite. one has a slit on the carb opening side and the second one has the slit on the slide side. the clear poly sheet was so much easier to work with versus the 1/16" aluminum. on my second prototype, i used a coping saw to cut notches/grooves on each side of the carb mouth so that i could seat the plate in. cut the plate slightly over sized, beveled the edges, and used that to seat the divider into the carb mouth. the poly plastic version was way easier to construct. razor blade to cut the plastic and cyanoacrylate (super glue) to mate the 2 dividers together.
For Your Information, the vertical divider may have an adverse affect on the fuel dispersion as the needle/slide rises and the fuel comes up from the main jet, but i cannot say for sure. while in a main jet tuning frenzy, i pulled the double divider and tune the carb. horizontal divider is good enough. but if you like try the vertical divider as well, that is up to you. i think i might make another prototype in which the vertical divider is not flushed up to the slide but spaced 1/8"-1/4" from the slide. currently i am running a different aluminum horizontal divider that i hastily fabbed up. there is a gap between the aft edge of the divider and the flat face of the slide of about 1/16"-3/32"". i think it is having an effect on the the way it responds from 1/4 to 1/2 throttle. the first divider i made was crafted so that it was flush with face of the flat slide and the response on the low throttle was better.
I'd like to here any results, you get trying this, im wording as you said what a vertical half would do air would be more equalised, but I understand even with horizontal air pressher may have diffrent affects on main jet, very interesting work, thank God there's people like you willing to try diffrebt things |
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Post by pete130 on Jun 15, 2022 3:45:25 GMT -5
Sorry to correct you there. The metering rods are 40$ with me and I take them back at full price as they are a non-wear item. (So does SC) I live at sea level and no hills, so I can't see myself buying a smart carb I may be old fashioned but I stick to what I know and that's just pwk type carbs with jets lol, but for what they cost in Australia I can't see it being $1000 better ride lol |
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Post by repherence2 on Jun 15, 2022 17:13:49 GMT -5
He explained over the phone that the Scooter market is very new to them and that within the scooter market there are very few Honda tuners. I got a good chuckle out of that, there are dozens of us Honda tuners  . The tech told me that they have limited experience tuning these motors and hes very happy to help but it wont be as easy as something like a GasGas 300 or KTM 300XC which they have lots of experience tuning. I was given specific instructions on what to do and how to do it then to report back with my findings.
yes there "are dozens of us Honda tuners" but only a handful of people would be willing to throw down the $ it takes for a SmartCarb or a Lectron.
sounds like you have become their first guinea pig in the Honda vert moped engine realm.
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. The tech told me that they have limited experience tuning these motors and hes very happy to help but it wont be as easy as something like a GasGas 300 or KTM 300XC which they have lots of experience tuning. I was given specific instructions on what to do and how to do it then to report back with my findings. He assured me with my engine and the needle provided I should have a great running scooter once we get the low end dialed in. He suggested I lean out the engine two clicks at a time until I reach a clean and stable idle, record my clicker setting and report back with my findings. He also noted that about 30 clicks of the metering rod is equivalent to about 1 needle clip position in a PWK. 
. The tech told me that they have limited experience tuning these motors and hes very happy to help but it wont be as easy as something like a GasGas 300 or KTM 300XC which they have lots of experience tuning. I was given specific instructions on what to do and how to do it then to report back with my findings.