Honda cbr250r

[Speedracer]

I'm gonna buy one (1987 hurricane model), any issues these things have I should watch out for?
I understand they are long lasting (100kkms+) good bikes, but I'm gonna do 1600km over a weekend to ride it home.. if it blows up I'll be real late getting back ;-)

[MattRSK]

Nice Choice.

[monkey99]

good choice, strong motors..got a CBR rr..even better but making me ride to fast..& its a matter of time before I either get sensible or a ticket..i hope the former :)

[vtec]

Let us know how much it cost. I've got one at the moment that I'm fixing up for a family friend (for cost price dammit).

Yep, great bikes. Check that the forks aren't leaking, check that the power is pretty smooth right up through the range (above 8000 all the way to redline), if so that means it's getting a good mix of fuel and air to all cylinders. Don't full throttle it below 10,000rpm. Let her warm up, and she'll treat you well. Make sure you check the oil level every time you ride it for the first few weeks, just so you know how much she is using. Some use more than others. Check chain tension and condition.

[bobsmith]

good choice, strong motors..got a CBR rr..even better but making me ride to fast..& its a matter of time before I either get sensible or a ticket..i hope the former :)

Well I'll hope the latter for you since the former generally is accompanied by getting too close to the aspalt or the scenary..... :doctor:

[Speedracer]

Let us know how much it cost. I've got one at the moment that I'm fixing up for a family friend (for cost price dammit).

Yep, great bikes. Check that the forks aren't leaking, check that the power is pretty smooth right up through the range (above 8000 all the way to redline), if so that means it's getting a good mix of fuel and air to all cylinders. Don't full throttle it below 10,000rpm. Let her warm up, and she'll treat you well. Make sure you check the oil level every time you ride it for the first few weeks, just so you know how much she is using. Some use more than others. Check chain tension and condition.

$2300 w 24000km
Yeah it has damaged fairings which is why it's cheap.
so these bikes do use oil normally? how much is normal? 1L / 1000km??
I'll be checking the forks and chain, but what things go wrong that are expensive to fix particular to this bike?

I've got a compression tester if anyone knows how much compression it should have.

Also why no full throttle below 10,000rpm?

[vtec]

Nah, it's nowhere near 1l/1000k's. It's probably close to 500ml/5000k's or 100ml/1000k's. But you have to keep it between the marks. The full capacity is about 2.4l. So if it changes by about 200ml, it might put it out of the correct level.

Some use oil some don't. My race one didn't used to, but it does now. Doesn't bother me though, cause it still runs sweet.

To use your compression tester, just compare all the different cylinders. If you've got one or two lower than the others, then you're losing compression. It's very rare that all 4 will be low on compression equally.

Don't full throttle below 10,000rpm, well I don't always stick to that rule. But it's because the engine is designed to rev. And full throttle below 10,000 is kind of lugging it a bit. It's just something that people have said on the CBR250 forums. www.cr-x.org/cbr250 This is a bloody handy site, and I have learnt heaps off it. There's a few very clued up people who are often quick to help. There's also plenty of cocks who just want to lecture everyone though.

[FlyingDutchMan]

$2300 w 24000km
Yeah it has damaged fairings which is why it's cheap.
so these bikes do use oil normally? how much is normal? 1L / 1000km??
I'll be checking the forks and chain, but what things go wrong that are expensive to fix particular to this bike?

I've got a compression tester if anyone knows how much compression it should have.

Also why no full throttle below 10,000rpm?

I've never had to top up the oil on my one... I just change it every 3000-3500km. Do change it regularly - 5000km at the tops. Its the one single thing which will extend the engine life.

Expensive things for the bike: any thing you try and OEM from honda (except oil filers for some reason). They rip off something chronic. I've had quote of $700 for an instrument cluster mount. made me very happy to pay $70 to a wrecker for one.

[imdying]

And full throttle below 10,000 is kind of lugging it a bit.Wouldn't the CV type carbs prevent this?

[Speedracer]

Don't full throttle below 10,000rpm, well I don't always stick to that rule. But it's because the engine is designed to rev. And full throttle below 10,000 is kind of lugging it a bit. It's just something that people have said on the CBR250 forums. www.cr-x.org/cbr250 This is a bloody handy site, and I have learnt heaps off it. There's a few very clued up people who are often quick to help. There's also plenty of cocks who just want to lecture everyone though.


Hmmm finally found the thread you're talking about... had a good look om there to see what kinda problems I could have...
http://www.cr-x.org/cbr250/forum/topic.asp?TOPIC_ID=35770

2 people in there saying it's bad, but no explanation.
What does lugging it mean?

[imdying]

Lugging or labouring the motor is when you're operating it grossly down in the rev range. For your example, in your car, using <1500rpm in top gear, you'll notice the motor struggles (or lugs, or labours).

Of course any motor suffers the same problem. A CBR250 will not labour below 10000rpm, that's crazy.. it's peak torque is somewhere near 11-13000rpm iirc. Bike motors are reasonably flexible, and since they're pulling less weight about they suffer from this less than say a car motor. Your motor will tell you what revs it wants to be in... if it feels sluggish, or feels like it's struggling, drop a gear :) Regardless, CV carbs will to a greater extent limit your ability to lug the motor because they won't open further than they need to, so it's pretty much a moot point.

[imdying]

Oh yeah, the NS250R will rape the 87 CBR250. Keep that instead :yes:

[vtec]

Yeah but keeping the NS250R going will rape your wallet. On gas, oil and maintenance.

[imdying]

A small price to pay. But having said that, maintenance isn't that much of an issue on those. You need to keep the ATAC valves clean, maybe twice a year, and they're not particularly heavy on oil. Definitely drink more petrol than a CBR250 though.

You'd probably keep the NS250R when you get a bigger bike, cause they're damn fun to ride. The early CBR250s have few redeeming features in comparison when you've got a bigger biker to contrast against.

/edit: Oh yeah, and the NS250R will wheelie off the throttle which the CBR250 won't do :D

[Speedracer]

Yeah but keeping the NS250R going will rape your wallet. On gas, oil and maintenance.

You don't know how right you are!

You can't get pistons for it anymore... OEM pistons $300ea... wrecker with $$ signs in his eyes, $500 for 2 well used pistons with 2 bores. Supposedly in excellent condition yet not capable of reaching minimum compression.
It took 6 months to find them and I looked at every alternative that exists. Most wreckers told me to buy new ones instead of being helpful.

Plus this model is well known for blowing pistons. Spoke to one guy who blew 6 (yes six) pistons. Then he cleaned out the exhaust which apparently fixed it.
Having now blown 2 myself in about 1000km (first one came with the bike, second one lasted about 100ks) I am fully aware that there are some low quality pistons. The ones that blew looked kindof matt silver, whereas the ones that are still going are both not matt silver textured. Not to mention the chunk looked fatigued rather than something hit it.

They blow the chunk of piston between the rings about the size of the exhaust port (and in the same place). After that my first one dropped the top ring, and after 400ks I blew the top bit off and it lost compression. Bike still ran with 1 piston till I got some more. I replaced the second one at the blown bit between the rings point.

And no, the NS250R only makes 45hp, same as the CBR... sadly no 2 stroke raping going on here..

And did I mention it sucks petrol like a dirty whore? I reckon I'm getting 10k/L...

It may be damn fun to ride but I want to be able to ride more than 20ks from home without worrying that the piston might blow on me.

[Speedracer]

Oh yeah, and the NS250R will wheelie off the throttle which the CBR250 won't do :D

Sure you're not thinking of a derestricted NSR250?

[imdying]

Naw, the good ole NS250R, one pipe up around your butt. Gas it to 6-1/2, back off, rip the throttle back on, she'll wheelie quite happily :)

You've had some back luck by the sounds of it. I managed 15000kms in 6 months without having anything blow up! (although I did snap an extremely abused chain :D)

Are pistons not available, or you just won't pay Honda $300 each for new ones? Have you talked to someone like HPE about the barrels? Perhaps having them cast iron sleeved? No idea if anyone in NZ can renicasil a bore, but someone here will know.

You can't blame the bike for blowing a replacement piston inside of 1000kms. That's entirely the fault of the person who fitted it (well, unless you thrashed it straight away). I think you'd find that a properly rebuilt top end would last you a significant number of kilometres.

Heaps of my mates did the rebuild with old pistons and barreks on NSs, NSRs, RGVS and RZs when we were younger and all kicking about on 250s... that was the first time I ever saw sparks (bits of ring) fly out of an exhaust (98 NSR) :lol: If you want to be able to ride more than 20kms from home without problems, you'll need to rebuild it properly, which is expensive yes.

[imdying]

And no, the NS250R only makes 45hp, same as the CBR... sadly no 2 stroke raping going on here..Don't be suckered by the false God of HP matey.

87 CBR250 has a pathetic 25.4Nm of torque
86 NS250R has a relatively healthy 36.3Nm of torque

Over 40% more torque ensures that NS will rape the CBR quite convincingly. The torque curve is also fatter and healthier on the stroker :)

[vtec]

Power, is proportional to torque times revs. Power is what's important for going fast. The CBR get's good torque up around 15,000rpm which means that it gets good power. The twostroke probably maxes out around 11,000rpm, which means that even if it does have more torque, the CBR still has a better multiplying factor on that torque. Power is what matters to me. The CBR250 is still quite a fast and fun bike. If you want someone to explain why they will be keeping their 250 fourstroke after they get a bigger bike, then talk to N4CR. They are a fast bike, not as fast as the 2strokes, but in the right hands they can keep up with most riders on 600's and 1litres through the twisties. I think I could beat 90% riders around a track with me on my CBR250, and them on an RGV250, or an NSR250.

[imdying]

Somewhat agree about the keeping 250 thing, but there's a couple mitigating factors in favour of the NS; he has it, it's a two stroke, it's faster than the CBR, the CBR is in Auckland; the CBR is an unknown quantity.

Torque isn't just proportinal to torque * rpm, it is torque * rpm (/5252). Power is important for maintaining speed, but torque is what gets you there. Compared to the NS, the CBR has little torque, and it's peaking out at 10,500rpm (and well petered out by 15000rpm). The NS makes peak torque at 8500rpm (and 40% more of it), and has a solid curve underneath that.

The multiplying factor doesn't actually matter because, as you've shown, it only relates to the amount of hp produced, and they both produce the same. As the NS has to build up less revs, it means you can get into the next gear sooner, keeping it in the sweet spot, where as the relatively low torque CBR has to drag itself across a broader (but lower) spread of torque. Even if you were short shifting the NS.

Whether you could be beat 90% of riders around a track on the CBR vs 2 stroke is irrelevant. With very few miles to familiarise yourself, you could beat you around the track on the NS vs CBR, and that's what matters.

However, regardless of whether it's a better/faster bike (they're very similar, except for the motors, the NS riding position is a little less armchair, a little more over the wrists), it just seems to me that $2300 + petrol + ferry would go a long way to sorting the NSs motor out, rather than buying an unknown CBR which is 1400km and two days ride away.

On that note, does the NS have a nicasil plated bore, I pretty sure it's a cast iron one (which means you can bore it). I wonder if a 0.5mm oversize piston is available from either TonyB or Honda themselves?

[vtec]

Just getting into semantics here, but power is proportional to torque times revs. the word 'proportional' allows for a proportionality factor, or a multiple, in this case you have said that it's /5252, so neither of us are wrong. Otherwise I would have said Power is equal to Torque times RPM.

I think you misunderstand how horsepower works. The smoother HP curve with a larger percentage of the rev range providing good power, is more useful power. Lets say a toyota Corolla puts out 100Hp at about 5,000rpm, and a 600cc motorbike puts out 100Hp at 13,000rpm. Both these vehicles will be putting out the same power at the wheels (assuming drivetrain losses are the same) even though the corolla will have to be geared higher to deliver that power at the same speed, if they were both the same weight (even though we all know the corolla is a lot heavier) they would both accelerate at exactly the same rate if they were both putting out 100Hp, even though the Corolla had to be geared higher to put at that power at that speed.

Torque is merely twisting force, Power is what makes you go fast. 45Hp is 45Hp whether you are putting it out at 10,000rpm or at 15,000rpm. If both of these bikes weighed the same, and were both at max power, for that instant they would both accelerate at the same rate. Now, due to the fact that the CBR has an extremely smooth power curve, that would mean that it can more easily be made to stay very close to it's max power figure, whereas the much peakier two stroke will drop considerably from that figure when you change gears. Thus it is more likely that you will keep very close to 45 HP all the time when you are racing the CBR. This of course doesn't take into account the fact that the NS250R is lighter, or that the NSR's and RGV's are lighter and noticeably more powerful. But is rather just an insight into the workings of HP.

Torque is equivalent to force
Work done (Joules) = force x distance (or) torque x revolutions (with a multiplying factor)
HP (Joules/Second) = Work done / Time (seconds)

The more work you can do per second is the amount of power that you put out. The longer you can keep the power level up the more work you will get done in the same amount of time.

I'm sticking to my idea that power is what matters in this case, yes I realise that the torque drops off after 15,000rpm, but it's a gradual loss, just as it is a gradual climb on the increase in revs below 15,000rpm. But the bike will be putting out quite close to it's max power all the way from 12,000rpm right through to 18,000rpm. That's 1/3 of the rev range to play with. Much more than you would get out of the 2stroke. You generally get about 1/4 or less of the rev range close to max power on the 2 strokes.

My point about saying that I could beat at least 90% of riders on 2 strokes around the track on my CBR was really just pointing out that they are not that much slower than the 2 strokes, and in fact the most important difference between the bikes is the rider. And if you couple that with the cost effectiveness and relative worrylessness of the fourstroke bikes, makes them in my opinion the better choice.

I think what you are saying about the NS250R having to go through less revs to get to the next gear change could have some minor impact, in the stored rotational momentum within the engine, but seeing as the engine parts inside the CBR are pretty small and light, and the fact that when you change gears your bike pulls the revs down, effectively converting that energy into the forward kinetic energy of the motorcycle. The fact that you can leave the CBR in the same gear for much longer than the 2strokes is actually an advantage (as long as you keep it close to the max power of the bike), as you do not have to change gears as much.

The only reasons why I could see the NS250R doing power wheelies if it does indeed have only 45Hp, would be that:
a: The suspension isn't up to much
b: The weight distribution isn't too flash
c: If it were much lighter than the CBR
Or any combination of the above. Hell my very quick RGV250 didn't even do powerwheelies. Or maybe you are changing the weight distrbution by giving a yank on the bars just as you approach max power, could be done.

P.S. I've owned a very fast RGV250 Race replica that had been set up for racing (I only used it on the road though) for two years, so I'm also speaking from experience when comparing the bikes. Give me the CBR over the RGV any day (not for outright racing though, although I wouldn't want to pay costs on racing twostroke 250). I know a guy who spends $5,000 a season keeping his RGV250 racebike running well.

[imdying]

Regardless of the semantics, and I agree, in the real world they're as much just that, that 40% extra torque still matters.

It's the amount of torque available at any given speed that limits the vehicles ability to accelerate. The more torque you have at any given speed, the higher your acceleration potential is.

The CBR pretty much has over 80% of its torque available at any revs, which is why it's more theoretically more flexible.

The NS on the other hand only has 80% of its torque available through 40% of its rev range, which means more dancing on the gearbox. It's worth noting however, that is has the same torque available as the CBRs 80% from about 3000rpm, so it is somewhat a moot point. It's also has more torque available from 6000rpm than the CBR ever has. It's also worth noting that both of these bikes require dancing on the box if you're getting the best from them, and if you're not getting the best from them, then well the whole discussion is irrelevant :D

[texmo]

I think I could beat 90% riders around a track with me on my CBR250, and them on an RGV250, or an NSR250.
mate you could beat 90% of riders on gsxr1000's....

[Mr. Peanut]

es through the twisties. I think I could beat 90% riders around a track with me on my CBR250, and them on an RGV250, or an NSR250.

:killingme

[NSR-Dan]

an NSR will kill a CBR on a track, ive seen them go up against and beat, Ducati999's, R1's and GSX-R 1000''s

it all depends on the rider, i guarantee you would get better lap times riding an NSR than your CBR

also another factor.

they may be the the same HP, but because the NSR is lighter its power to weight ratio would be better than the CBR.

also as the NSR was designed as a GP bike for the road. and is designed around an RS250 frame, the engineering is slightly better and is a lot more manoverable than the cbr so would hold a higher speed in the corners. also because it has a lower rev range it would hit its peak earlier making able to accelerate out of a corner quicker.

im not biased as i have driven both, i own 2 NSR's and buying a CBR250RR shortly

[N4CR]

If you want someone to explain why they will be keeping their 250 fourstroke after they get a bigger bike, then talk to N4CR. They are a fast bike, not as fast as the 2strokes, but in the right hands they can keep up with most riders on 600's and 1litres through the twisties.
Simply fun bikes and you don't always have to loose your liscence on them (although it's easy enough..). Pretty solid too (the CBR in particular then zxr) and crash well. To be fast/keep up with squids etc you HAVE to learn how to corner like mad brake late and push your luck, makes you a better rider in the end. But that's the fun for me. Well not so much lately but I just ain't been riding as much though...

As with 2 strokes 250s being much quicker in a line... well, not a whole lot actually, have gone against a few and they don't do a whole lot more top end wise - 20ish or so km top speed more ain't a massive big difference really, they do flick in a bit quicker due to design and being 10-15kg lighter. I'd really like to see one in action though properly. Outta the power band they are toast though :lol: hehehehe. I matched an rs250 to 180k+ quite a few times, it was dead even for some reason, it has been rebuilt a while back but I just think it needed tuning cus it should have beaten me, well I friggen hope so anyway... my zxr seems to go a little bit better than the rest of the 4's anyway, had some stuff done :first:

edit: yeah they'd kill 'em around a track though.. but the 4's could keep running day in day out with just oil changes every 5-6k :P

[vtec]

:killingme

Well, maybe you are in that 10%.

Oh yeah, and good post N4CR.

[Speedracer]

anyway any tips on cbr issues?

[vtec]

Ok, the issues that I have had are listed below. This is over a long period with several of them:

Hmm, I've only had the usual stuff like a clutch cable, a chain, brakepads. Oh yeah I seized the calipers because of mismanagement when changing the pads. Nothing really bad to point out about these bikes. They are definitely the pick when it comes to 250 fourstrokes. If you do all the maintenance there is no reason why you can't get over 100,000k's and possibly much more.

If you want problems that people have had... go to: www.cr-x.org/cbr250 and go to technical issues forum on that site.

[NSR-Dan]

Oh yeah I seized the calipers because of mismanagement when changing the pads.

yeah when chaning pads dont pull on the lever as you can pop the pistons out of the calipers if there is no pads in them.

[vtec]

I seized the calipers because the pistons were way out so the pistons got covered in shit, and when I pushed them back in for the new pads they were sticking, and causing the brakes to drag. Use some brake cleaner on the pistons before you push them back in... maybe a bit of a brush or a rub down with a rag.