Lets assume that your setup is a true Currie setup but I'm not sure that truely is. I know there is a second motor that is supposed to be a Currie (upgraded) motor but I've never seen it but maybe you have it. Here's a link to Currie's standard kit setup for the USA. http://www.ezipusa.com/category.php?id_category=8
As you can see it's quite diferent then what you have. Not to say your isn't still a Currie kit though. On a Currie bike they have a s# on the frame and I think it may even have a manufacture date. But not on the kits. So there's no way to know when yours was manufactured.
To my knowedge there are only 3 ways to increase the speed on a Currie while leaving the motor in it's current location. 1) you can get a slight speed increase by going with better batteries (lipo or lifepo4). These batteries will have much less voltage sag thus giving you a little more speed (1 or 2mph). 2) increase the battery voltage. This will likely require a new controller, additional batteries and maybe a throttle so the power lights still work. If this is a direction you decide to take I would recommend contacting the guy in my link and send him pics of your setup. You likely have something simular and would need to do some of your own rewiring though. He could at least supply you with the controller and recommend a throttle. You could also consider buying the standard USA battery rack. But that would be very expensive because you would also need the batteries. But you could still do the conversion and strap a second battery to the top of your existing rack. 3) a lot of guys in the USA replace the freewheel that currently has a 20t gear with a new freewheel with only 16t gear. These freewheels can usually be bought on EBay for under $20. But be sure it is a LEFT HAND FREEWHEEL. This will increase the top speed from around 16mph to around 20mph. However, you will also loose torque so speed gaid will be much slower. Currie motors come in different sizes as well. These conversions have been mostly done on 450w motors. I'm guessing yours maybe only a 250w motor though. The guy that started doing all these freewheel conversions claims he has converted 1 250w Currie and it still increased the top speed the same.
So if your goal is only for more top speed the cheapest thing to do is a freewheel replacement. But if you want more speed and not loose torque more voltage is what you need. REmember, the faster you go the more battey power it consumes.
Last edited by dumbass; 01-02-12 at 09:08 AM.