RS125 Top Speed?

[johnsmith222]

Hi.

I was wondering if anyone can clear this up for me. A friend of mine is wanting to get into biking and I believe he is being mislead by some other riders as to the top speed of the bike he is interested in.

He's interested in the RS125 because of it's looks and claims of it's top speed.

I guess you could say that I just got my ass handed to me by three bikers who confirmed that an RS125 can do 130mph. I was arguing that was impossible and that it can only do around 90mph in unrestricted form. Possibly hit 100 on the speedo.

It's worth noting these bikers have 600 and 750 sports bikes so don't really fit into the pedboy stereotype, although they are young.

I am asking the top speed of an RS125 (I have a fair idea myself but I am asking for him rather than me).

It's just that when you have three people confirming the top speed being 130, you begin to doubt yourself.

Oh yeah, we're talking in unrestricted form with a power valve, exhaust etc.

Normally I couldn't care less if someone exaggerates performance figures of their bike, but as I feel he is being mislead about a bike he is interested in I think he should hear your opinions. (don't worry, I like the RS, but I don't like people misleading my mate).

[chris-red]

An old (the old ones are faster) RS in standard unrestricted form should see 100-110mph maybe a little more with a decent exhaust and the right jets. it wouldn't see 130mph without serious work.
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[Pete.]

130mph is about what speed 125cc motogp bikes make, so decide for yourself if a roadgoing bike can get there with jets and a pipe
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[binge]

[iooi]

[craigs23]

My CG used to break 100, so I'd expect an RS to be a bit faster than that.

(Please note, all speedo readings for 125 bikes are read in kph when discussing rates of velocity on the internet).

[Kickstart]

Hi

130 isn't even vaguely possible (that's about the top speed of an RS250)

Early ones are faster (better exhausts, larger carbs, etc) and they managed 100mph in road tests, give or take a gnats (very rare for them to get over a true 100mph, most got 99.something). They might manage another 1 or 2 mph with the gearing raised a tad, but suspect that would make 6th gear far less useful when there was a head wind. They definitely had a touch more top end power than the AF1 Futura which had the same top speed, hence why I suspect 1 tooth down on the back might be possible.

However the speedos are compulsive liars. I have had mine round to 185kmh (115mph), which isn't even vaguely believable. Similarly I have had almost 160kmh (100mph) with a pillion. At the top end the speedos seem to over read by at least 10%.

Not sure on the GP bikes. The 125 singles they use now were quite a bit slower than the old twins but they have had over 20 years to make up that performance deficit. With the aerodynamics of a Honda RS125 the Aprilia road bikes put out about enough power to hit about 118mph. Many years ago PB had a 125 frenzy and had an MBA 125 twin there which managed 142mph through the timing lights.

All the best

Keith
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[Spit-Fire]

[mistergixer]

[Mord]

New shape with Arrow exhaust system but standard VHST28 carb and standard sprockets 16-40 it will go 103mph indicated* (with 17-40 a little bit more).

But you can improve it further with i.e. VHSB32 carb. If you want more then you still can get that with some engine tunning. But to be honest RS125 is not about top speed in my opinion.

*- roughly 5-10% higher than real speed

[MinhDinh]

Restricted + 89 kg me does 82 max. (Speedo)

I can't imagine it doing better 100
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Hit the G spot.

[Welshd1k]

had one clocked at 100 (cb600 speedo) today and it wasnt even howling...

it even pulled away from my 33bhp hornet and the guy wheelied it in 2nd and changed to 3rd doing 70+ no fucking jokes i got shown up by some chav on a rs125 with l plates in a straight line .....


i think it wasnt a 125 tho as it span the back wheel up out of a roundabout and had a VERY narow powerband. aka no power YAP chage gear yap change gear thinking it had a 180cc kit .oh and it had no ignition
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[Ariel Badger]

[Villers]

Its a pointless exercise really though isnt it. If these people are thick enough to believe that you can hit 130mph with about 25hp at the rear wheel then theres not much you can say that is going to change their mind

All you can do is tell the lad as best you know and then let them make their own mistakes
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RS125 > CBR6 > SV650S > ZX636R > GSX1300RZ Hayabusa > 06 RSVR Mille > SV1000S > Street Triple 765 RS

[Mord]

130mph it's Aprilia RS250 territory.

Aprilia RS125 will do max 110mph.. but tuned one.

125cc GP bike is a completely different bike and different story.

[Frost]

The RS250 will struggle to do a genuine 130mph, won't do it as standard on the flat.

The 125 GP bikes during qualifying were setting top speeds of between 195 and 210kph, so thats 120-130mph. But keep in mind that aerodynamics are very important. The riders will have leathers & helmet designed to be as aerodynamic as possible on that bike. The bikes have no indicators, lights, numberplate, they can set the ride height and suspension for minimum ground clearance without having to worry about speed bumps etc.

I've yet to see anybody who claims 100mph out of an RS125 actually do it under test conditions, even with just me following them on a bigger bike. The speedos are about as accurate as holding a licked finger up.

[Welshd1k]

[Kickstart]

[Welshd1k]

[radical]

I believe that the Honda rs125 is capable of between 140-150 mph but thats a full blown race machine, the Aprillia would normally top out at about 95-100mph but explode very quickly if used in a high state of tune, If you want to go faster buy a bigger bike and enjoy the reliability as well as the performance.

[Jayy]

I had an RS 125 which was fully standard apart from had that bridge in the CDI broken, which I believe did something to the power at 6000rpm? Not sure what but I know it had been done as I noticed it when looking at the CDI.

That bike struggled to hit 90, think 85 was the quickest I'd had from it.

[stevo as b4]

I've seen magazine road test time the 2002-2003 RS125 at between 93 and 96mph, which i assume was an actual speed achieved. The very lastest 2008> RS125's have got no chance of 100mph without some work tbh! Superbike found that the 2009 version puts out just 20bhp r/w on BSD's dyno, and it coughed and spluttered it's way to a genuine 80mph at Bruntingthorpe. they said it was very peaky even for a 125 and had nothing below 7k and couldn't even pull top gear until over 6k rpm, or it would slow down. The new ones are really horrible things with the restrictions forced by emissions regs, and the std exhaust and carb settings kills alot of the performance that they used to have as std.

[radical]

[binge]

[radical]