Owning a 125 2 stroke...

[craigs23]

...what do I need to know?

I've never owned a 2 stroke before, but I'm tempted to look for one (most likely an Aprilia RS) as a project/fun/toy bike.

I've read the odd post here and there, about how easy the strokers are to work on, but what do I really need to know in regards to:

Frequency of engine rebuilds - what's likely going to be needed on a regular basis - when, what and how much?

2 stroke oil - I understand that this is burnt in the combustion chamber and is fed from a separate tank - is this much like a secondary fuel tank - how much is needed over what kind of distance?

Fuel consumption - likely to be a lot lower than what I'm used to from a 125 bike, but what sort of figures am I to expect?

Any major difference between the newest RS125s and the older models? Other than looks, obviously - are they both similar in terms of maintenance schedules/reliability?

And lastly - anyone care to post some pictures of their own models, and your thoughts/stories of such little beasties?

[Paulington]

Frequency of engine rebuilds - what's likely going to be needed on a regular basis - when, what and how much?

On most 2 stroke 125s you are probably looking at once every 10k miles, Aprilia suggest the first rebuild at 16000km so around that distance. As for what it's usually just a piston and cylinder, probably costing you around £200-£400 or so.

2 stroke oil - I understand that this is burnt in the combustion chamber and is fed from a separate tank - is this much like a secondary fuel tank - how much is needed over what kind of distance?

Yes it is like a secondary fuel tank, most 125s just put a small tank under the seat to put the oil in. My 125 uses around a litre of oil per 25 litres of fuel, 25:1 ratio which is about right as that's what my Kart uses also which is a Rotax 125.

Fuel consumption - likely to be a lot lower than what I'm used to from a 125 bike, but what sort of figures am I to expect?

My 125cc does about 100-120 miles to a FULL tank (including reserve) which is 13 litres, it is not good on fuel at all haha.

Any major difference between the newest RS125s and the older models? Other than looks, obviously - are they both similar in terms of maintenance schedules/reliability?

Yeah going to be similar, they are hardly different besides a bit more power and looks that I know of.

And lastly - anyone care to post some pictures of their own models, and your thoughts/stories of such little beasties?

My bike, it's the same as a Derbi GPR125R:

https://i176.photobucket.com/albums/w182/OllieePaul/GileraSC125.jpg

As much as I love the bike, as flickable and fun as it is I just find it lacks power. I enjoy being able to turn my right wrist and something to happen, whereas if you're in 2nd gear or above on the 125 you just don't get that.

HTH. .
____________________
"Four wheels move the body, two wheels move the soul."
Current Vehicles: '89 Kawasaki KDX200, '99 Yamaha XV535, '00 Honda ST1100 Pan-European, '08 Suzuki GSX-R1000, '08 Mitsubishi Lancer GS4 2.0 TDCi, '15 BMW 1 Series 116d Sport Turbo.
CBT: 27/08/08. Theory: 04/09/09. Module 1: 16/09/09. Module 2: 01/10/09.

[MarJay]

[ms51ves3]

[Fahd]

Just to add my 2-pence, I've owned an Aprilia RS50 and Aprilia RS125 (the latter for 2 years) and never had to rebuild either of them once, they'd both also always start on the button very quickly.

I think a lot of people underestimate how much damage riding these things without warming up does to them. I found warming up for 5 minutes before riding gently for at least a mile before thrashing it kept it pretty well looked after.

Having said that you might want to test-ride before buying anything, I find the Honda CBR 400RR far more entertaining and I don't have the worry of my engine blowing at the back of my mind every time I ride it with some enthusiasm. So I doubt I'd ever go back to one, it's great when you're 17, not so great when you can ride whatever you want. Here's my old little beast (the yellow and grey one) with my cousins, back when we were 17:

https://www.bikechatforums.com/files/dsc01772.jpg
____________________
I Ride: Honda CBR 400RR.
I Drive: Audi S3.

[MarJay]

[ms51ves3]

Mine sits at idle with the choke on while I shut the garage door and put my helmet and gloves on.
Knock the choke off, give it a few revs going up to 4,000rpm and letting it drop to 2,500rpm, probably do that for about 20 seconds.
Get on, ride under 5,000rpm, wait until the temp gauge drops due to the thermostat opening, then once it moves back up to temperature I know it's safe to ride like a hooligan.

[Philious]

I bought an RS 125 in June this year and parted with her a month ago for my GS500e, I think they are under rated and mainly slated for the unreliability due to the 17yr old riders not warming the engine thoroughly.

Very quick little bikes, they just want you to over take at every opportunity and great handling too, a couple of times i found my knees scarily close to the tarmac whilst riding out wearing jeans....

Mileage I found did depend on how often I pinned the throttle fully open.

As for the 2t oil as stated don't rely on the light, just pop your key under the seat and use your eyes to see how much you've got, you have to do it with the tank anyway so one more thing to check won't hurt.

https://img.photobucket.com/albums/v330/flippy2k4/DSCF2137.jpg
____________________
Previously; Honda XR125 - Yamaha DT125r - Aprilia Rs125 - Suzuki GS500e, Currently; Kawasaki ZX6R + ZX10R
Theory : Passed 28/7/09 Module 1: Passed 21/09/09 Module 2: Passed 23/09/09

[Andy C]

I loved and hated mine. Was always careful to let it stand to warm and use the best oil but still ended up having to pay for a top end (wasnt machanically minded enough back then to do it myself) which worked out expensive.

Great handling but after the top end went I found myself quite paranoid about it happening again and although it was great to ride wasnt practical at all (though im sure you would be using it for summer days).

Think I actually perfer my RXS as is a 2 stroke but seems to have more character (though slower, worse brakes/suspension/frame/wheels/everything).
____________________
99 RS125 --> 02 SV650s --> 03 Speed Four --> 92 RXS100 --> 93 CB400sf --> 01 CB600f Hornet

[Philious]

I miss the old RD 125 Lc, a mate of mine had one a few years ago and that was a sweet bike. They just don't make them like they used to.
____________________
Previously; Honda XR125 - Yamaha DT125r - Aprilia Rs125 - Suzuki GS500e, Currently; Kawasaki ZX6R + ZX10R
Theory : Passed 28/7/09 Module 1: Passed 21/09/09 Module 2: Passed 23/09/09

[Kickstart]

[G]

I've been a bit disappointed by the suspension generally on RS125s, (my rs250s were a bit lacking at the front too, though apparently the later model was better). NSR was fine when I had it, but I suspect wouldn't feel so great now.
If it was for 'keeps' I'd definitely consider budgeting for some aftermarket bits.

Saying that, I still found the RS250 perfectly adequate for road work, where it being a bit soggy at the front didn't limit my riding.
Never been that impressed by the brakes either - ok and do the job, but lacking the 'sparkle' of something like the yamaha blue-spots.

[Kickstart]

[G]

[Kickstart]

Hi

The 125 calipers are nothing like the 250. The 125 uses Grimeca calipers (marked as Aprilia).

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[serlant]

my 125 (kawasaki KH125 k7) takes about 13 litres without going into reserve and does probably 180 miles to a tank, with about 4 tanks to 1 litre of 2 stroke, and i think its stil on the origional top end with 16k miles on it, no other maintenance than adjusting the chain and changing the oil once in the 3k miles i put on it.

[G]

Oh well, looked similar to me at a cursory glanced and presumed their damp performance was related.
https://www.maxmoto.co.uk/images/Aprilia%20RS125%20MotoGP.jpg
https://www.motorcyclespecs.co.za/Gallery/Aprilia%20RS250%2000.jpg

I wonder how the latest one with a radial calliper matches up?

[Kickstart]

[prawny1]

Best advice would be use the best quality auto mix two stroke you can afford change the rings regularly as a service item rather than wating untill they break up, and let your engine warm up before riding it hard or at all.

oh and engine breaking is not your friend on a two stroke due to high load and low lube / mix going into your engine.

[G]

Yea, can't see the 'radial' bit being the over-riding factor, but so far all the bikes I've ridden that have bothered with radial callipers have had good brakes. Presumably if they're going to the money/effort of doing them, they're going to do them half-decently.

I'm sure it won't be too long before they're on cheap Chinese bikes with appropriate performance, however .

[Mord]

[craigs23]

Thanks for all of the responses I'm a bit closer to making my mind up about whether to truly get one or not. As mentioned, I've never had a stroker before and can definitely see the appeal - even the regular tinkering away in the garage is a bit of a plus point for me.

I'll have a nose around the local papers to see if I can get something at a reasonable price - I think if I can get an Extrema-like model with some change left over for some parts would be ideal.

Thanks again.

[ms51ves3]

[27cows]

Sporty 125s are entirely pointless and ridiculously expensive in relation to the ludicrous fragility of the engines (and most other components) and poor performance compared to a bigger bike.

Why would anyone in their right mind buy a bike that is going to require constant attention?

[Kickstart]

Hi

Personally, because they are fun, and you can thrash them pretty hard without going at silly speeds. Because they are in a fairly high state of tune and you need to get it right to get the best from it. Unlike anything much larger (including 250 2 strokes) where you can be far lazier and still make good progress. Same can apply to even smaller 2 stroke (I have an unrestricted 50cc gag bike as well), just that they land up being too slow for any great distance on major roads, while a 125 can happily keep up with the general flow of traffic on the motorway.

Sure a 400 4 stroke will be far quicker, but to me nowhere near as much fun.

Fast does always mean fun. Fast normally means you cannot use the performance so are just sitting round at boring revs.

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing