Hugely expensive (comparatively speaking) and allows you full control over the entire fuel injection system (at least, in my design). The thing is, it's really not worth it for the 125. I originally made it as both a test-bed (with an eye towards other bikes) and for my own use. So it supports launch control, boost control, Nitrous Oxide, real-time barometric pressure correction, quick shifter, air shifter, and a lot of other things.
So, on my 125 I added Nitrous Oxide to it and it makes 100% more power
It's a riot - but it's an expensive one. For most people, they would only go to that extreme on a different bike. From most 125 rider's perspectives, probably the most useful thing is the adjustable rev limiter. Being able to raise it to 14,000 RPM has been a real benefit as my camshaft will spin up there. In my own case, the Quick Shifter, the Nitrous, the Launch Control - all of those things are very valuable and were incorporated into my 125 for both testing and fun (with an eye to mass production).
For most 125 riders I suggest this;
- Performance Pack
- Carbon Fiber Clutch Kit
- Tires
- Suspension Modifications
If a guy goes that route it's not a lot of money and it's all incremental expenses. The return on investment is huge, especially when you get into proper tires and the suspension modifications and combine them with the 'Pack and Clutch. On the suspension side, you can turn the bike into a corner-eating monster and it's a riot. 80K corners? You can hit lots of 'em at 140 with the bike right on it's side. Nothing can keep up with it that I've run against. And it's cheap, and it's easy.
When you look at it financially;
$99.95 for the 'Pack (less springs)
$124.95 Carbon Fiber Clutch Kit
+/- $250 - New Z rated Modern Tires
$10 - PVC Pipe for adjusting front forks
$484.90 - all in. That's peanuts. Most people run to the exhaust store and spend that much on exhaust. And it only makes the bike slower! It doesn't fix any of the deficits in the bike's design at all.
When you come out the other side of it (the list above), you have a bike that beats
everything on short straights and sharp corners. And it's a ton of fun and it's reliable and it looks great and gets unreal fuel economy. My 600 gets about 35 miles to gallon - if I'm not honking on it. If I honk on it you can practically watch the fuel gage go down as you ride. In contrast, my 125 got 80 when being beaten mercilessly all day and over 100 in stock trim. Also, insurance is very little for the 125 and you can park it anywhere. It's also WAY safer then the 600 especially with the suspension and tire modifications. When you've got those it really becomes impossible to dump it. I don't know how a person could. But it's a riot and you can push it right to the end and still remain shiny side up.
It's a fact that I'm going through the 600, spending lots of money on it, and am trying to dial in the suspension so that I am replicating.....wait for it....my 125. I won't be satisfied with the suspension on the 600 until it at least equals, and preferably exceeds, the 125. And what did it cost to do the suspension on the 125?
$10 worth of PVC pipe and new tires. That's really cheap considering I can buy Ohlins front forks for my 600 at a cost of
$17,000 USD......
So the lowly 125 actually isn't. It's one of the neatest things out there. If you can't get more speed from it for a reasonable price
go in a different direction - go into the handling side and find out what it's like to nail corners at rates that freak out your friends while you know you could have hit that last one (that freaked them out) much harder yet, with complete safety.
This is really important because it rounds out riding ability. 99% of the riders out there buy a CBR 600 and nail it down the straights and then lace on the binders and plow it through a corner - at posted speed limits - or less. This is because they don't know how to ride. The 125 is the perfect platform to nail down ALL aspects of riding. This means straights, corners, rain, wind storms - all of it. When you go into something like the 600 - all of that foundation comes into play. But, for some reason, it seems like 99% of motorcyclists always want to go fast in a straight line. That's what cars are for
Put 110's on it - GOOD ones, set the rider aboard sag, adjsut the preload with a cut piece of PVC pipe, lower the bike in the forks a little...and...presto! Instant MotoGP hero in the making. And with the 125, you're not removed from the ride at all. You're right there, at ground level, and every part of you is making the bike do everything it's doing. On the 600, this is somewhat removed. You're up higher, you have 107 horse, its very different. The 125 is not a 600 and the 600 is not a 125....at least, not yet....