4T 500cc -> 2T 125cc?

[Ingah]

Having just read the YZF125 thread https://www.bikechatforums.com/viewtopic.php?t=182928 - a few comments on there have had me thinking about 2stroke 125s, especially posts by G and Kickstart.

What are these 2 strokes really like to own and use for all weather commuting and A-roads? Am thinking of the supposedly reliable Japanese bikes like the NSR125, and less about bikes like the RS125 which i've heard all too much about

I'm a little confused regarding them though because people have always said 2T bikes are unreliable and need alot more maintainance - that the fuel consumption is bad and that if you derestrict them they eventually go pop as they can't take being at full power. And also that they could hot-seize if you say travel at constant throttle for a long stretch (hot-seizing sounds very dangerous indeed), and that they have a very pronounced power band (last thing i'd want is a sudden unexpected burst of power)

Contrast to that a quote from G in the earlier mentioned thread: "Later, I got a 2 stroke and realised I had wasted my money on the 4 stroke. The 2 stroke was perfectly reliable - as they are, faster, more fun and a more sensible road bike. "

I'm a student (so money is important - definately enough so that i end up doing most bike maintainence and work myself), riding a restricted old CB500 at the moment (fast but cheap i was told - immeasurable repairs aside ), but am beginning to come to the conclusion i'm not really enjoying it like i should be - i'm finding it abit of a heavy deadweight (for want of a better term). I still have my old CG125 and am actually quite tempted to go back to it (especially for the fuel economy and lightness), if it weren't for the fact that i don't think the drum brakes are really safe, and that it just truly hasn't got enough power for my needs.

Would i be better thinking about one of these 2T 125cc bikes? What about the list of "2T problems" earlier? I got my CG125 as my first bike and avoided the 2T because of these reasons, but i do have abit more experience now.

Thoughts?
____________________
-- Ingah

[27cows]

I think 2 strokes are seen as less reliable as they are traditionally easier to tune (and amateur tuning usually leads to seizures/snapped con rods/etc). But in my personal experience, 2 strokes can often be more reliable and more durable than 4Ts.

Some of the less frenetic older strokers, such as the RD125LC, AR125 and DT125R can all reach decent mileage (40-50,000) with a bit of TLC.

I've had the same 2 stroke bike (RXS100) for over 19 years and it is without question the most reliable thing I've come across, taking into account the simplicity, cheapness to run, lack of maintenance required and speed with which it can be pulled apart and put back together again. The current engine has done 70+K miles with nothing more than decokes and a new plug every 5000 miles, and a change of gearbox oil every 10-15K.

2 strokes aren't as good on fuel (particularly the unrestricted stuff like NSRs). But if you don't do stupid things (such as using K&N filters, Micron pipes and other 'tuning' mods) then they can be as reliable as the 4 strokes, with the bonus of being faster and easier to work on. I also like to see a nice haze of blue smoke in the mirror

I've done 400+ miles in a day on several 2T bikes - the RXS, MZ251, LC125, GT500 and a KH125 - with no bother at all (well, except to my arse/back ).

[wupwup]

i think if you look after them they are just as good or better, but you need to know how to look after them. basicaly they are easier to wreck but if you know how to avoid wrecking it theres no reason it wont last.

[Kickstart]

Hi

The servicing is more different than more common.

Most 4 strokes need the valves adjusting. Have more frequent oil change intervals. Have more to go wrong (and more expense when it does go wrong), and need to be revved harder for the same power (power is torque x rpm, 2 strokes make more peak torque so do not need to rev as hard for the same power).

However 2 strokes need the 2 stroke oil topping up, use more petrol (although not massively more), give the plugs a hard time and tend to have a peakier power delivery (although that is more down to them being built to be quicker).

The RS does need the rings changing pretty often (and fail to do it and the bill gets bigger), but most 2 strokes are not too bad. People seem to manage about 30000 miles on the NSR before the rings need doing (the RS has massive ports for a road bike for more power, the NSR has a bridge over the exhaust port to give the rings a far easier life at the expense of a bit of power).

What you feel as a peaky power delivery is the torque. The 4 strokes tend to have a flatter torque delivery while the 2 strokes tend to have the torque increase more with rpm. However none of the modern ones are particularly peaky (old non power valve 2 strokes were more fun in a way as the power tended to come in with more of a thump).

Don't worry about them seizing on a constant throttle. Only reason that is likely to happen is if someone screws up the jetting (probably as a result from some dodgy idea of tuning), and the same can happen with a 4 stroke.

I have seized 2 strokes quite a few times, but mainly my old MBX125 with Allspeed exhaust, S&B filter, etc. Think every seizure came from trying to use a pattern piston . Also blown up a few 4 strokes (for an example, piston from my better halfs CB125T 4 stroke after a conrod snapped).

By the way, the NSR was a product of Hondas Italian business.

While I do like small 2 stroke (even a 50cc 2 stroke I have) and find them fun to ride, if it is only transport and you have a full licence I would be more inclined to point you at an RD350ypvs, although they are now going up in value.

All the best

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

[tvr321]

I think that arguments in favor of the 2 strokes are valid when you are restricted to a certain displacement, 125cc for example. But since you are comparing a 500cc 4t to a 125cc 2t, there's not really much going for the stroker.
I own an NSR and I although it is a lot of fun, a 4 stroke 500 can do everything with no drawbacks.

[Seb]

Sounds like nothing some wide bars, better tyres and a suspension overhaul couldn't fix. The little 500s are top fun if you stop thinking of them as boring old commuters
____________________
2010 Triumph 1050 Sprint ST

[calyx]

125 2T vs 400 4T is a more fairer comparison in my opinion.
____________________
Boris - London

[Damon]

[Alasdair Murison]

2T 125 = fun fun fun!!!

probably not the best for commuting on, or holding at high revs on a fast straight section of dual carriageway A road, but when the weather's good, and you find a nice clear section of twisty B road....... Not much is better...

sex.... well ye, but it's close!!!
____________________
MY 2008 Aprilia RS 125
Passed test : 15/08/08
Riding since : 15/06/08 (17th Birthday)

[calyx]

They definitely are true head turners because people wonder what kind of lawn mower is approaching.
But! When you change gear they will know that it is a lawn mower with gears Maybe a geared chainsaw..
To me 2 strokers are a bit embarrassing.
____________________
Boris - London

[G]

Well, suppose I should stick a reply in .

I used my NSR daily for commuting and as my only means of transport for some time and didn't have any problems I wouldn't have had on other bikes (ie leaking forks, loose chain.)
In town I preferred the NSR, but get out of town and I'd take the NSR anytime over a CG; when you're straining to accelerate and there's trucks boxing you in on a duel carriageway it's not so fun.
A bit more care does need to be taken on warming up - they will go wrong quicker if abused, but will be cheaper to fix if it all goes wrong.
Regular maintenance needed is pretty cheap.
The cost of 2 stroke oil should be factored into the equation, but I found the NSR fairly frugal.
I'd say the NSR still has a fairly pronounced power-band, not so much that it'll catch you out with a kick, but more that it's obvious you need to rev it to get going.
However, compared to a CG, it may well make as much power as the cg at peak revs when it's not even in the powerband! CG will be geared lower as stock however.

Saying all that, were it me, I'd probably stick with the CB. If it's low power you like and want to mix it with some sportier handling, how about something like a Suzuki Goose? A claimed 33hp from a 4 stroke single in a quite lightweight chassis.

It could be worse trying a sports 400 or similar, presuming you don't want to go up to a 600 of some kind - these tend to have a bit more of a 'lively' and 'light' feel.

[ms51ves3]

[calyx]

[G]

Sorry, I presumed it was the type of sound not volume -
2 stroke sound tends to carry less far than 4 stroke sound in my experience - this is causing problems for a lot of dirt-events where there's a lot higher percentage of 4 strokes now.
A standard road legal 2 stroke 125 may be a bit louder than a standard 4 stroke 125, but stick a loud can on both and the 4 stroke will be much louder.
Ridden at the same speed, the 2 stroke will no doubt be quieter.

[Newbiker0507]

[ms51ves3]

[Pernig]

[evoboy]

Love using the x7 (250 2smoker) round town and down twisty lanes. Keeps up with my mates in those instances easily... (even with a crap carb setup and coked up silencers )

Not so much fun when doing longer distances though, pull out the ZX for that.

Its these 125's and 50's with 'fart' cans that sound crap...
____________________
Suzuki GT250 x7------- Fazer 600------CB250RS------Aprilia Rally 70----- Bandit 600

APT Motorcycles

[Alasdair Murison]

[calyx]

I don't know much about 2T cans but every single of them is just irritating me. Watching tv with some peace and my alarm goes off because of a 2T.
Maybe only chavs are riding 2 strokers nowadays..
____________________
Boris - London

[G]

Or maybe you don't hear the ones with standard cans, because they're so quiet .
It's the pit bikes with loud cans that annoy me - so much noise and so little go (though plenty enough for the pavement/alleyways they're used on, of course.)

[Kickstart]

Hi

Can't see a 2 stroke setting off a car alarm (unless the rider crashes into the car). Round here the ones you hear are the 4 strokes, including those you can hear thrashing it down a straight road about 2 miles away.

2 strokes make more power than 4 strokes. Why want some slow old 4 stroke commuter lump rather than a 2 stroke designed for performance . Next you will want a diesel as the 4 strokes sound too annoying .

All the best

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

[ms51ves3]

[chris-red]

[Ingah]

Thought it might be worth an update as i'm still thinking 2-stroke (i almost can't stop thinking about 2-strokes!)

The CB500 already has Bridgestone BT45s (i got them put on shortly after initially buying the bike), and am looking at buying and fitting some universal Renthal handlebars (mine are very slightly bent at the moment due to crash damage and it does my head in), and replacing the rear shocks with a new Hagon unit (i'm getting bumped around very badly on these poorly maintained Welsh roads), especially since i found out how easy it is to change! Restrictors come off in less than 2 weeks too (can't wait for my unrestricted license)

I've been having a better time with the bike recently anyway (despite having done nothing to it yet), it's getting better with the weather i think
I'm hoping the improvements will make it even better to ride, to the extent where i will stop thinking of other bikes.

Circumstances have changed a little anyway. I've managed to secure a student house for next academic year with a garage (which everyone else rightly sees as "mine" ), which means that i'll be fully able to keep 2 (or more!) bikes (and/or a semi-project bike), and i can work on them in the dry (so fettling and repairs will not have to wait for summer, which were major downers in the back of my mind against buying "what i want" over "what it's sensible to have"). I'm also less concerned about having a shiny bike because it will be inside, away from prying/jealous eyes. Crashing remains a small concern, but i think i just need to get over it, i've been riding constantly for nearly 2 and a half years on "sensible bikes" (even currently doing it for a job! And i've booked Bike Safe ) and i think by now the incidents i've had have got me out of the silly no-thought-front-brake-grabbing which has caused me to go down on bad surfaces multiple times.

I can't help but continue to eye up the NSR, it just looks so (whilst not being heavy - relatively - or expensive to insure/replace parts on like a 400/600 sports), and the idea of trying a 2-stroke out really appeals to me; it would be almost a shame to miss out on the opportunity to. It even almost seems like the Alfa Romeo of the car world (if you listen to Top Gear anyway), in that you're not a proper enthusiast until you've tried one (a 2-stroke that is). It'd need to be an old cheap one (maybe even one that is already broke, so i can fix it up how i want it to work, rather than be stuck with the previous owner's potentially stupid choices), so i just need to get some money together and go out looking

The exhaust note of a 2-stroke is unlikely to bother me anyway, and providing it's of a reasonable volume (this house IS in a city after all), i don't think it will unfairly wind the neighbours up either.

Random thing that strikes me as odd is that the RXS100 (that i hear so much about on here in a positive way) appears to do (spec-wise) 100mpg whilst producing 11/12bhp, similar to the (restricted) NSR, which only does something like 45-50mpg. I really can't work that out.

Unfortunately, the RXS looks so much like the CG125 that it's put me right off it.

Random ramblings aside, does anyone know of any dealers around Bridgend/Cardiff areas that are likely to sell/stock older (cheaper) NSR125s (as that does appear to be the most likely/affordable option at the moment). I'd ideally like to at least have a go on one over the next few months, and if the price is right, i'll take the plunge (keep the CB500 as well, would make a nice combination i think )
____________________
-- Ingah