Tag Archives: YZF-R125 Power Commander

Debunking airbox mods On Yamaha YZF-R125? – part 1

Ok so this seems to be an ongoing urban myth, whether it’s chavs drilling the airbox of their mum’s Fiesta 1.1 popular or little 125s, or even big bikes, people seem set on the idea that airbox designers are actually our mums who are trying to sneakily slow our bikes down. or something.

Why am I even going down this road?

On my bike I’ve shown the exhaust side of the engine quite a lot of love and attention, but despite the nice, big-bore shiny pipesness, she continues to run better with a little baffle in the end, like so:

The best reason I can come up with that the bike runs better with a smaller diameter exit/baffle in the end (effectively restricting the flow again) is that perhaps the exhaust is a bit much pipe for the bike – and by that I mean for the amount of air the engine is moving, the pipe diameter gets too wide at the end, which ends up with the gasses slowing down too much and actually impeding scavenging of the exhaust system. Or maybe there’s some sort of sound-waves stuff going on like with two-strokes.

Either way with the baffle in you get a little bit of torque around that 70mph point where you shift into top gear. With the open pipe it didn’t have the oomph to push through that but with the baffle it does (albeit slowly).

A couple of months ago, under what turned out to be ideal conditions on a private runway, thanks to that baffle we hit 85mph.
That was on a 15t front gear too so would have needed even more torque to make it through to the power band.

And it was absolutely equal parts terrifying and exhilarating..,as you would expect flying along on a glorified moped! 😀

Continue reading Debunking airbox mods On Yamaha YZF-R125? – part 1

POWER COMMANDER V Map switching Test run & topspeed on the 13:48 gearing

This is just a quick video to test how well the gopro clone footage comes out on Youtube. Hopefully it doesn’t mash it up too bad.

In this run I’m testing out the map switching function on the Power Commander V, having just hooked that up (more on that soon), and also there’s a top speed run to see what the max speed it could reach was, on the 13:48 gearing (13 tooth front sprocket, 48 tooth rear).

This is part of my ongoing testing and tuning of my 125.

White ’08 Yamaha YZF R125

Not really sure where to start to I guess start at the beginning and will work up to date from there…

I’ve been into messing with cars for years, mostly mk2 golfs but only got into bikes sorta by accident when I fell in love with stretched scooters (they’re ridiculous, I know). Somehow along the way I got the idea that I’d quite like to do the blood bikers thing and realised that i’d need a geared bike to get a proper license in order to do so… So after some online research, concluded R125 was the way to go. A friend happened to have one sat in his garage (see pic above, as I found her he’d since got a blade and was bored with the 125) so I did my CBT and here we are…

Continue reading White ’08 Yamaha YZF R125