vino'n'ukes
11-19-2007, 09:14 PM
This is a very long post that probably challenges some of the conventional wisdom around here about how to approach modding a 2-stroke scoot. I’m not intending this as a troll, but rather as some long-needed help to those who come to this board looking for help in getting more pep, safety, and utility out of their 50cc 2-stroke while not sacrificing dependability or fuel economy… or attracting too much attention with loud pipes and screaming revs. Unfortunately, many of those most often offering advice here seem to assume that everyone is looking for a street version of a race bike, and will be happy with the sacrifices in dependability, economy, and tractability that entails.
A little over a year ago, I got an already de-restricted 2002 Vino Classic with 1300 miles on it in an even swap from a friend in exchange for one of the custom ukuleles I build professionally. At the time, it seemed perfect for what I wanted… a fun and economical ride primarily for beer and grocery runs and the occasional pleasure ride. It didn’t take too many miles for me to realize that the bike would need both chassis and engine mods to haul my fat butt (225lbs +/-) around safely, comfortably, and with enough grunt to keep up with suburban traffic and pull hills without too much bogging. First, let me explain that I’m an old guy (60) who has no boy-racer aspirations, no need to attract attention to myself, and no desire to piss off my neighbors.
To attend to the safety and comfort problems, the first things I did were to increase the safe load capacity and improve ride and handling by installing a set of Pirelli 3.0 X 10 SL26s and a Jog 90 rear shock (direct bolt-on replacement and cheap) to beef up the rear spring rate and damping. I also installed a Slipstreamer Spitfire aftermarket mid-size windshield to reduce drag and increase comfort. These things did a lot to improve the safety, comfort and handling (as well as going a long way toward correcting the wildly optimistic speedo), and I rode it like this for another 1000 miles… but it really needed more oomph. At about 2300 miles I started the engine and tranny mods.
I’m a retired research engineer and an ol’ “shade tree” mechanic, and a lot of the modding advice being offered to folks like me on this forum didn’t seem to make much sense to me. I fully understand how a 2-stroke engine, acoustically tuned exhaust, and CVT transmission work, but the “conventional wisdom” approach (y’know… Stage 1, Stage 2, Stage 3,… Stage Full-Freakin’ Race!) seems more appropriate to the track (or using the street as a track). Further, I kept seeing posts that insisted that you’d get more reliability out of wringing everything possible out of 50cc rather than immediately going to a 70cc kit… BULLSQUAT! Horsepower comes from two sources: revs and torque… and torque comes mainly from displacement and compression ratio. Since both high revs and high compression greatly increase stresses, displacement is the only sure way to increase horsepower without reducing dependability… if it is done right.
I went with a Polini Contesta cylinder kit. It’s a cast iron, two-ring kit with moderate compression ratio from a known manufacturer at a good price. Remember… I was looking for dependability and durability as well as displacement. Yeah, I know that cast iron takes a bit longer than aluminum to warm up, but I find that if I start the bike first it’s pretty well warmed up by the time I put on my helmet, shades, and gloves.
For exhaust, I chose the NCY 1830A-5AU-0010 performance street pipe available from that guy in British Columbia. It’s a Taiwan-made pipe that is essentially a freer-breathing version of the stock pipe, and looks very similar. It is most decidedly NOT an expansion chamber pipe, and I made that decision deliberately. I fully understand that a 2-stroke will realize its maximum horsepower potential when it’s in the middle of the power band of a tuned expansion chamber pipe, with the back pressure wave assisting in scavenging, etc., and that is certainly perfectly appropriate for the track where the CVT does a pretty good job of keeping the engine revs in the power band all of the time. BUT… you usually don’t encounter stop-and-go traffic on the track like you certainly do on the street. The power band of a well-tuned expansion chamber pipe is pretty narrow, and the torque outside that band sucks. The standard fix for the racy crowd for decent performance off the line is to install really stiff clutch springs that don’t allow the clutch to engage until the engine revs are up into the power band… but that is obviously not a very good solution for creeping along in stop-and-go traffic. There is a very good reason why most scooter manufacturers don’t fit expansion chamber pipes on stock scooters… and this is it. I wanted the nice, broad power band a non-expansion chamber pipe gives you -- even if it doesn't make as much absolute power -- for tractability in traffic. The exhaust note of the NCY sounds pretty much like a bit louder and throatier version of the stock exhaust, but it is not loud enough to attract unwanted attention from the cops or grouchy neighbors. I also wanted the “stealth” stock look to avoid attracting notice from law enforcement.
To help realize the potential of the 70cc upgrade, I traded the stock 14mm carb out for the ubiquitous Arreche 19mm, but I kept the stock airbox to avoid intake noise and tuning problems. I did remove the intake snorkel from the airbox to allow a little more intake airflow. Carb tuning was no big deal, and I wound up using the #95 main jet supplied with the carb and lowered the needle to the top notch to avoid a too-rich burble at mid-throttle. The plug chops look fine. While I had things apart replacing a dry-rotted and cracked intake manifold, I replaced the stock reed petals with carbon fiber. I knew this was unlikely to improve performance on my low-rev engine (and indeed it didn’t), but I did it for peace of mind in case of reed failure.
As to tranny mods, I installed a Malossi Multivar – originally with the supplied 7 gram weights – and switched out the stock torque driver spring for the Malossi white one that came with the Multivar kit. I also installed slightly stiffer 1500-rpm clutch springs. After experimenting with both a Malossi Kevlar belt and a conventional Bando belt, I decided the Bando gave quicker response and a slightly higher top speed (I think the Malossi kevlar is a bit too stiff for a mildly tuned bike).
I stuck with the 3.0 X 10 rear tire and the 7g rollers for quite a while, but wasn’t happy with the harsh ride and the feeling that the overall gearing was a tad too low. Rather than going with a taller final gear set, I decided to try to save money and kill two birds with one stone by switching to a 3.5 X 10 rear tire. As feared, the limited stock suspension travel (even with the stiffer Jog shock) had the tire bumping the underside of the storage compartment on road dips, so I shelled out too much money for the Malossi rear shock that has adjustable spring preload and about 1-1/4” more travel. The taller gearing gave me one or two more mph on the top end, but the big improvement was in the ride and handling… much more like a bigger scoot now. I did have to extend the centerstand to accommodate the bigger tire and longer shock, but a couple of “bulldog” wire cable clamps from the hardware store did the trick with no welding needed. Of course, the scoot was less quick off the line with the taller gearing, so I experimented with lighter roller weights. Currently I’m using 5g which make up for most of the lost “jump”, although I’m still slower in the first 30 feet than I was with the 3.0 X 10 tires. I have a Malossi yellow torque spring on hand that I’ll probably try to see what effect it has.
To compensate somewhat for the drum brakes, I installed Malossi vented performance brake shoes a short while ago. They give good, fast, controlled stops at the speeds this bike is capable of, but they squeek a little bit when applied at low speeds.
So… what are the performance numbers? The de-restricted stock bike topped out at 41 mph with my 225-lb. weight. Now, it does an HONEST 50 mph (flat road, no wind, two-way run, speed measured with a bike computer calibrated by both a roll-out and timed distance). Prior to the drivetrain mods, zero to 30 mph times were an average of 9.8 seconds; now they’re 7.0 seconds. On a long, fairly steep, constant grade (a very long, very high bridge I travel nearly every day), the scoot used to bog to a steady 33 mph; now it pulls the hill at 42. Of course, these numbers would be considerably better if you’re some skinny 160-lb. guy. The acceleration is smooth, steady, and turbine-like. I can cruise easily on rolling suburban roads at 43-45 mph.
I’m really happy with the performance of my little Vino now. It’s a much safer, quicker, better handling, and more comfortable scooter. It has been dead reliable in the 1500 miles since I did the engine mods. Never pushed or carted home; never failed to start. In weather above 50 degrees F, it starts immediately with either the electric starter or a kick. In colder weather, it definitely likes to be kicked the first time, as the larger engine load on the little starter motor probably pulls down the voltage to the CDI too much. After it warms up, though, it starts fine with electric.
I expected the performance improvements, but I was pleasantly surprised at the fuel economy. It got about 75 mpg before the mods, and I fully expected that to drop into the 60-65 mpg range. I was amazed that it now gets 70 mpg, day-in and day-out (and I ride fairly hard, often with heavy cargo, and always accelerate at WOT when traffic allows). And it runs just fine on 87-octane regular pump gas.
Here are a couple of pictures of the scoot:
http://www.glyphukulele.com/files/vinoside__2_.jpg
http://www.glyphukulele.com/files/vinorear__2_.jpg
No smartass comments about the basket please… this scooter was built as a utilitarian hauler, not a showboat. Between the basket and the bag hook I added, I can easily carry five grocery bags in addition to a 12-pack of longnecks under the seat!
So… if you want a quicker, safer, more comfortable (but still dependable and economical) 2-stroke Vino (or any other similar 50cc scooter), and don’t feel the need to call attention to yourself or to try to extend your penis, I suggest you give this recipe a try. I’ve already done all the work.
Sorry for the very long post…
Dave
A little over a year ago, I got an already de-restricted 2002 Vino Classic with 1300 miles on it in an even swap from a friend in exchange for one of the custom ukuleles I build professionally. At the time, it seemed perfect for what I wanted… a fun and economical ride primarily for beer and grocery runs and the occasional pleasure ride. It didn’t take too many miles for me to realize that the bike would need both chassis and engine mods to haul my fat butt (225lbs +/-) around safely, comfortably, and with enough grunt to keep up with suburban traffic and pull hills without too much bogging. First, let me explain that I’m an old guy (60) who has no boy-racer aspirations, no need to attract attention to myself, and no desire to piss off my neighbors.
To attend to the safety and comfort problems, the first things I did were to increase the safe load capacity and improve ride and handling by installing a set of Pirelli 3.0 X 10 SL26s and a Jog 90 rear shock (direct bolt-on replacement and cheap) to beef up the rear spring rate and damping. I also installed a Slipstreamer Spitfire aftermarket mid-size windshield to reduce drag and increase comfort. These things did a lot to improve the safety, comfort and handling (as well as going a long way toward correcting the wildly optimistic speedo), and I rode it like this for another 1000 miles… but it really needed more oomph. At about 2300 miles I started the engine and tranny mods.
I’m a retired research engineer and an ol’ “shade tree” mechanic, and a lot of the modding advice being offered to folks like me on this forum didn’t seem to make much sense to me. I fully understand how a 2-stroke engine, acoustically tuned exhaust, and CVT transmission work, but the “conventional wisdom” approach (y’know… Stage 1, Stage 2, Stage 3,… Stage Full-Freakin’ Race!) seems more appropriate to the track (or using the street as a track). Further, I kept seeing posts that insisted that you’d get more reliability out of wringing everything possible out of 50cc rather than immediately going to a 70cc kit… BULLSQUAT! Horsepower comes from two sources: revs and torque… and torque comes mainly from displacement and compression ratio. Since both high revs and high compression greatly increase stresses, displacement is the only sure way to increase horsepower without reducing dependability… if it is done right.
I went with a Polini Contesta cylinder kit. It’s a cast iron, two-ring kit with moderate compression ratio from a known manufacturer at a good price. Remember… I was looking for dependability and durability as well as displacement. Yeah, I know that cast iron takes a bit longer than aluminum to warm up, but I find that if I start the bike first it’s pretty well warmed up by the time I put on my helmet, shades, and gloves.
For exhaust, I chose the NCY 1830A-5AU-0010 performance street pipe available from that guy in British Columbia. It’s a Taiwan-made pipe that is essentially a freer-breathing version of the stock pipe, and looks very similar. It is most decidedly NOT an expansion chamber pipe, and I made that decision deliberately. I fully understand that a 2-stroke will realize its maximum horsepower potential when it’s in the middle of the power band of a tuned expansion chamber pipe, with the back pressure wave assisting in scavenging, etc., and that is certainly perfectly appropriate for the track where the CVT does a pretty good job of keeping the engine revs in the power band all of the time. BUT… you usually don’t encounter stop-and-go traffic on the track like you certainly do on the street. The power band of a well-tuned expansion chamber pipe is pretty narrow, and the torque outside that band sucks. The standard fix for the racy crowd for decent performance off the line is to install really stiff clutch springs that don’t allow the clutch to engage until the engine revs are up into the power band… but that is obviously not a very good solution for creeping along in stop-and-go traffic. There is a very good reason why most scooter manufacturers don’t fit expansion chamber pipes on stock scooters… and this is it. I wanted the nice, broad power band a non-expansion chamber pipe gives you -- even if it doesn't make as much absolute power -- for tractability in traffic. The exhaust note of the NCY sounds pretty much like a bit louder and throatier version of the stock exhaust, but it is not loud enough to attract unwanted attention from the cops or grouchy neighbors. I also wanted the “stealth” stock look to avoid attracting notice from law enforcement.
To help realize the potential of the 70cc upgrade, I traded the stock 14mm carb out for the ubiquitous Arreche 19mm, but I kept the stock airbox to avoid intake noise and tuning problems. I did remove the intake snorkel from the airbox to allow a little more intake airflow. Carb tuning was no big deal, and I wound up using the #95 main jet supplied with the carb and lowered the needle to the top notch to avoid a too-rich burble at mid-throttle. The plug chops look fine. While I had things apart replacing a dry-rotted and cracked intake manifold, I replaced the stock reed petals with carbon fiber. I knew this was unlikely to improve performance on my low-rev engine (and indeed it didn’t), but I did it for peace of mind in case of reed failure.
As to tranny mods, I installed a Malossi Multivar – originally with the supplied 7 gram weights – and switched out the stock torque driver spring for the Malossi white one that came with the Multivar kit. I also installed slightly stiffer 1500-rpm clutch springs. After experimenting with both a Malossi Kevlar belt and a conventional Bando belt, I decided the Bando gave quicker response and a slightly higher top speed (I think the Malossi kevlar is a bit too stiff for a mildly tuned bike).
I stuck with the 3.0 X 10 rear tire and the 7g rollers for quite a while, but wasn’t happy with the harsh ride and the feeling that the overall gearing was a tad too low. Rather than going with a taller final gear set, I decided to try to save money and kill two birds with one stone by switching to a 3.5 X 10 rear tire. As feared, the limited stock suspension travel (even with the stiffer Jog shock) had the tire bumping the underside of the storage compartment on road dips, so I shelled out too much money for the Malossi rear shock that has adjustable spring preload and about 1-1/4” more travel. The taller gearing gave me one or two more mph on the top end, but the big improvement was in the ride and handling… much more like a bigger scoot now. I did have to extend the centerstand to accommodate the bigger tire and longer shock, but a couple of “bulldog” wire cable clamps from the hardware store did the trick with no welding needed. Of course, the scoot was less quick off the line with the taller gearing, so I experimented with lighter roller weights. Currently I’m using 5g which make up for most of the lost “jump”, although I’m still slower in the first 30 feet than I was with the 3.0 X 10 tires. I have a Malossi yellow torque spring on hand that I’ll probably try to see what effect it has.
To compensate somewhat for the drum brakes, I installed Malossi vented performance brake shoes a short while ago. They give good, fast, controlled stops at the speeds this bike is capable of, but they squeek a little bit when applied at low speeds.
So… what are the performance numbers? The de-restricted stock bike topped out at 41 mph with my 225-lb. weight. Now, it does an HONEST 50 mph (flat road, no wind, two-way run, speed measured with a bike computer calibrated by both a roll-out and timed distance). Prior to the drivetrain mods, zero to 30 mph times were an average of 9.8 seconds; now they’re 7.0 seconds. On a long, fairly steep, constant grade (a very long, very high bridge I travel nearly every day), the scoot used to bog to a steady 33 mph; now it pulls the hill at 42. Of course, these numbers would be considerably better if you’re some skinny 160-lb. guy. The acceleration is smooth, steady, and turbine-like. I can cruise easily on rolling suburban roads at 43-45 mph.
I’m really happy with the performance of my little Vino now. It’s a much safer, quicker, better handling, and more comfortable scooter. It has been dead reliable in the 1500 miles since I did the engine mods. Never pushed or carted home; never failed to start. In weather above 50 degrees F, it starts immediately with either the electric starter or a kick. In colder weather, it definitely likes to be kicked the first time, as the larger engine load on the little starter motor probably pulls down the voltage to the CDI too much. After it warms up, though, it starts fine with electric.
I expected the performance improvements, but I was pleasantly surprised at the fuel economy. It got about 75 mpg before the mods, and I fully expected that to drop into the 60-65 mpg range. I was amazed that it now gets 70 mpg, day-in and day-out (and I ride fairly hard, often with heavy cargo, and always accelerate at WOT when traffic allows). And it runs just fine on 87-octane regular pump gas.
Here are a couple of pictures of the scoot:
http://www.glyphukulele.com/files/vinoside__2_.jpg
http://www.glyphukulele.com/files/vinorear__2_.jpg
No smartass comments about the basket please… this scooter was built as a utilitarian hauler, not a showboat. Between the basket and the bag hook I added, I can easily carry five grocery bags in addition to a 12-pack of longnecks under the seat!
So… if you want a quicker, safer, more comfortable (but still dependable and economical) 2-stroke Vino (or any other similar 50cc scooter), and don’t feel the need to call attention to yourself or to try to extend your penis, I suggest you give this recipe a try. I’ve already done all the work.
Sorry for the very long post…
Dave