Aprilia RS 125 Top Speed

The Aprilia RS 125 top speed is dependent on a few factors. First and foremost, whether or not the bike is restricted or derestricted. A faster RS125 will probably also have a few performance modifications a good front/rear sprocket setup and being lighter can also having a lighter rider can make a bike quite a bit quicker.

The biggest limiting factor in the Aprilia RS 125 top speed is whether or not the bike has been restricted or derestricted. In learner-legal, restricted mode the bike puts out just 14bhp but when derestricted develops a claimed 33bhp. 14bhp should be good for about 70mph flat out but with a fully derestricted RS 125, you’ll be getting closer to 100mph at top speed.  

Derestricting your Aprilia RS 125 to get a full power RS125 is pretty easy if you can follow instructions and have rebuilt the RS 125 top end before. Since 2003, Aprilia RS125s have four restrictions: an electronic restriction in the CDI (break with a screwdriver), the lack of a powervalve system (purchase and install), the catalytic converter in the exhaust (must be removed), the 28mm carburettor in place of the 34mm carburettor (purchase, replace and rejet). Remember, you can only ride your derestricted (33bhp RS125) if you have your A2 or full A licence (at least in the UK). You also need to tell you insurance company about derestricting the Aprilia RS125 otherwise you could get into a lot of trouble!

You can increase your Aprilia RS 125’s max speed after derestriction, but doing so can get very expensive, very quickly. The RS125 was designed to handle well and through twisty roads it can keep up with (or even outpace) much bigger bikes with skilled riders. You can spend an awful lot of money on your RS125 only to find that you haven’t gained that much on your top speed. Playing with the front and rear sprockets can give you a bit more on your maximum speed but at the expense of acceleration. Remember not to play around too much though as you could make your bike unrideable!

If you do want to adjust your RS125’s sprockets to increase your bike’s maximum speed, then take a look at these statistics to figure out what would best suit you and your preference when it comes to riding your RS125: A 13 tooth front and a 36 tooth rear should give about 90 mph on a derestricted bike and 0-60 in about 5 seconds. A 17 tooth front and 40 tooth rear should give about 100 mph on a derestricted bike and 0-60 in about 6 seconds (this is the stock Aprilia configuration). A 15 tooth front and a 36 tooth rear should give about 110 mph on a derestricted bike and 0-60 in about 7 seconds.