Hey guys, got a late model Vino with the fuel injected 50cc. I need to get some more speed out of her, as she's slowing down traffic. It's dangerous to get passed by cars all the time. Not looking for anything crazy, just another 10mph more would do me. Right now it tops out at 40mph and sounds like it's hitting a governor of some sort. Seeing as how it's FI and even has a check engine lightbulb, I'm guessing it also has a computer. Wondering if anyone has any idea on how to unlock it.
Hi Ido, I don't think it's as simple as just unlocking it. You can purchase ECU programmers but be wary of these because it's highly likely you'd invalidate your warranty (if you still had one) and if done incorrectly it can also damage your motor. If you get the right cable you can connect the ECU to your laptop and after downloading the software, get performance data readings. 40mph is about normal for a standard Vino. Has it got a stock CDI and if it is hitting a limiter how many revs is it doing? If you want more power you are better of changing mechanical components than changing ECU software.
An aftermarket variator will get you 50mph just... It must have some form of derestriction as stock the limit is 45kmh. If you "remap" the Ecu you don't get a huge increase in top speed, but it is noticeable.
so JUST an aftermarket variator can get me faster top-end???? How? I thought the variator just controls how fast the thing upshifts... Does the variator change the pulley size (ie final gear?) That would make sense. I believe the engine has more room to go, as when it reaches top speed, it sounds like it hits a little rev limiter.
I've never really studied much into it, but it's something to do with the taper of the variator pully.
Alright, well, I finally figured it out. After days of research, I finally came up with the formula to unlock this little scoot. The answer to top speed is in the gearing people. Unless you get your engine to spin faster, your wheels aren't going to turn faster, and I am not looking to make the engine itself turn quicker. I'm fine with it revving to a safe 8000 or whatever Yamaha deems a good RPM limit. They do make taller Primary Gears for these bikes, however. Now, this will make the bike have less torque and reach speeds slower, so we'll need to squeeze out more power with a big bore kit. This is where it gets tricky, because when you increase the bore diameter, you must likewise increase the fuel. So a fuel management controller is necessary. I found a kit for about $450 that has both, a big bore kit (piston, cylinder and rings) as well as a fuel map controller. Then to make it shift better and better use the power, I'm going to go ahead and buy a variator as well so I can tune how it shifts. I want to be able to get off the line pretty quick, but not TOO quick as that'll put excessive wear on the belt and rest of the drivetrain. The sum total of my expenses comes to about $550 or so, depending on where I source the stuff. There seems like a big difference in price between the various vendors for the same kit, so shop around folks. Here's a point of contention for me. The kit I found comes with a 44mm piston, putting it at around 74cc, a good 50% increase. Another kit comes with 77mm AND a custom head. The head has been milled and has larger intake and exhaust ports (not sure about valves, 16.6 and 15.5mm, but not sure what stock is), but I'm not sure the larger diameters mean much, as the rest of the intake and exhaust system remains the same, with the same choke points. The other kits (with the heads) are more expensive and don't come with fuel controllers (a must). I wonder if I can't just have the head milled and widen the ports myself with my air dremel/carbide bits.
Nice looking scooter. That's a fair lump of cash for the little increase that you are looking for. Personally I would put the extra cash into a bigger engined scooter. They do a 125 version of it. Or if you are a competant mechanic, dump the lump, change it for a carburetted one complete with the none fuel injected loom and ancillaries. More room for tuning at a lot less money.
Yeah. That's a better option. Tuning a 50cc 4t injection motor is a lost cause really. They are built to be cheap and fuel efficient. A reprogram of the ECU might free up a bit of power, but putting a bigger bore isn't really going to be noticeable unless you have lots of hills. I could go into explaining rotating mass and inertia, but I won't bore you with that. The variator will for sure give you a bit of extra power.
The ultimate goal is to have higher top speed. While I'd like to have better take-off, I can live with the power of the engine the way it is now. I fear that upping the gear ratio will completely kill my take off. I wonder if changing and tuning the variator would get me decent take off and still give me the high top-speed. These parts are only about $150... I want to stay with the 50cc so that I don't have to have a motorcycle license. I also want to stick closer to the fuel economy of the 50. The idea to switch it back to a carb is a very interesting one. I wonder if the system is not too smart to realize this and throw a CEL. Might mess with timing. I'd probably have to fool it with resistors in place of the injector/fuel pump.
If I recall it doesn't even have a lambda sensor or MAF sensor. It's just TPS, pump, injector and ignition pickup. If you know anyone with a lathe you can mill some weight from your flywheel and clutch for better pull off
At the expense of engine smoothness. I've made up my mind that I'm not going to purchase the Big Boy kit for $850, which comes with the 76cc cylinder/head/fi control/gears/rollers. That's just too much. It's way cheaper to buy these things peace-meal. So I can get the gears and variator and see what happens. It's a huge job to do a big-bore kit on these vinos, so that can be done separately if needed after the gear swap. I do have to wait a few weeks to get the title to this bad boy before I buy anything. It's still registered to a friend.
To break it down on how these are "limited" for you: The initial restriction is the ECU for 45kmh bikes, but it also limits the fuel in. (if you plugged it into the yam diagnostic machine you would know what I mean) Then the variator is the next step. It's something to do with the taper of the surface. I've never dug into the physics of it, but aftermarket ones do give more power and speed. Then the final drive ratio comes in. Self explanatory I think. After this it's REAL tuning coming into play. The intake diameter, valve duration, bore size, rotating mass etc etc. You can of course use an aggressive cam in a stock motor and see some difference, but to really feel it the ECU will need a remap etc etc If you follow what I mean?
the fuel controller that comes with the big bore kit I found has adjustments for low mid and high, but I'm not sure it does anything for timing. I do know that the bike goes faster with the gears, but I bet the RPMs stay the same. Any word on whether the speed is controlled by controlling the RPM, or does it actually reach out to the speedometer somehow? I bet it just limits RPM and the speed is just a result of the gearing. Taller gears = more speed at max rpm. I think I'll buy the gears and variator first and see what happens.
I just found another big bore kit that gives 75cc displacement for $190, but doesn't come with performance head or fuel control. I found Fuel Control module for only $180. The guys selling the bbk really suggest the head with the larger valves. I wonder what sort of performance gains I'll see with just the stock head. I did plan on porting and polishing it, however, and improving the flow, but I'm not sure that can compensate for small valves. So the two kits I'm considering are $400 for 70cc and fuel controller, or $370 for 75cc and fuel controller. If I don't plan on upgrading the head, maybe I should stay with the lower cc? Or there is the 60cc kit w/o head for only $100, and that one I think for sure I can get away with stock head. I've read even the 60cc makes a notable difference.
I always say there is no replacement for displacement... But I'm not sure there will be much difference between the kits. Porting is worth doing simply for the better fuel economy.
I just got a message from an ebay seller claiming that the stock head would not work with a 75cc kit due to water jacket compatibility. Can anyone confirm/deny this?
