mate of mine just got an '08 RS125 but he feels its too slow and needs more power! Does anyone know how to squeeze more out of them?
Cheers!
trade it in for a bigger bike? 
I know a couple of people that race tune the Aprillia RS125 (which I assume you mean, given that I think Honda have stopped making theirs and thus wont have an 08 model)?? I’ll dig out their numbers in a mo.
:D:D:D
Is it restricted or full power ?
Best person is http://www.bobfarnhamtuning.co.uk/
I was always amazed at seeing how fast people like Joey Dunlop used to go round the TT on a 125 aswell, also the 2-stroke 125cc were also very quick going round places like Brands ind, so yeah tuned 125s can go quick but can he?I presume your mate is fairly young=silly insurance cost or a fairly new rider hence the 125cc instead of a bigger bike.
In the end it’s still gonna cost a lot of money whatever stage of tune you do to a bike, then again he could spend £400 and go on a California Superbike Course and he’ll be faster and corner better, without the extra power.
He could end up spending hundreds of pounds on a 125cc and only gain only a few extra bhp plus lose mpg, especially if its a little four stroke engine only to lose it all once he sells the bike on or if the bike gets nicked (the insurance I’m sure won’t refund the tune costs), but…if he becomes a faster rider by investing in training and track days, he’ll be fast on whatever bike he will buy 
thanks for the responses guys.
@ powerpuffgirl, i doubt he’s gonna wanna spend alot of money on tuning it, he’d rather get a bigger bike.
@ gurniman, he’s not sure if it’s restricted or not. Its got powervalves (which are in the exhaust?) but not sure if thery’re working very well/at all.
And yea, he hasn’t got a full licence so can’t get a bigger bike yet.
BTW, am i dreaming or did rs125’s used to be nutty bikes (before they tightened up emission laws etc?). Anyway, thanks, i’ll pass on the advice, particularly about doing his test and getting a bigger bike!
He’d know if it was unrestricted, believe me 
derestricitng a restricted rs125 is quite a lot of work, too - it involves the CDI, powervalve and exhaust, I believe
Of course, if your mate brings it to my gaff I can tell him if it’s restricted or not
yup bang on! but you can do the CDI yourself. search the net for pics. or PM me for more in depth details.
Basically involves cutting a wire in the CDI and filing back up with silicon. The power valve is a strange one and you’ll need a professional the only problem is its a bit of a lottery as to wether your bike is equipped with one. unfortunately when the bikes are built for some unknown reason they dont all have them - something to do with import and export to certain countries i.e. UK must be resrticted to 13bhp (fully derestricted they will put out about 33bph without exhaust and carb mod)
He’d know if it was unrestricted, believe me
derestricitng a restricted rs125 is quite a lot of work, too - it involves the CDI, powervalve and exhaust, I believe
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Yea, he said there wasn’t really a powerband so i’m guessing its not derestricted. Can you work on these then? If so, i may well tell him to pop over!
@ photographichero, yea he said he was thinking of changing the CDI, but didn’t say anything about cutting wires and silicone etc. Thanks anyway
The power valve is normally not connected and the CDI mod is quite simple.
Look on the Aprilia forum. You can’t post, but there is a lot of info to search.
There’s also the 125cc Sportsbike Forum (where many members of the Aprilia forum went when the 125 section was closed).
For further speed improvement, you can install a 34mm carb, and get it jetted correctly.
And the other half of us went to www.tjtuning.co.uk/forums
2008 model u need to drill a hole in the CDI to remove the enviro dip
You’ll need a race pipe to get rid the cat in the exhaust, this could be arrow or ginallie or any of the top makes or you could get a pre 2003 standard exhaust. Not sure on the fittings for 08 bikes tho
As for the powervalve it might have one already but if not u need one to be installed, this involves the blade (into just above the exhaust port) then cable to the solinoide (thing that pulls it) then wired up into the loom (Im pretty sure they have the connection installed even if they came out the factory restricted)
Other than that if you want more power do what I did, 150cc big bore kit, Flat top VHM head, Wiseco single ring flat top piston, 34mm carb, pipercross cone filter and a ginallie exhaust system.
The thing FLEWWW
Those be some nice mods 