Kawasaki Ninja 250 - New Thread, 12/2008

[neverdie]

those crazy 250s

I really love those crazy 250ies

[JonnyF]

Thailand doesn't have such restrictions, so for decent power needed on hwys, the 650's are much better value. For heavy Bkk traffic a CBR150 is arguably as good (or better) and half the price.

Surely you could turn that argument on it's head and say that the Ninja 250R is a better touring bike than the CBR150 and a better bike for heavy Bangkok traffic than the ER6n/f?

It's sat directly between the 2 bikes in terms of price and performance so it just depends what you're looking for. When I was looking at trading up for the ER6f I decided against it because the plus side of an extra 40 kph top end and more overtaking power wasn't worth the negatives of the decreased range, another 110,000 baht, less manoeuvrability for my daily commute in Bangkok and (in my opinion) a less attractive bike. Others would choose a CBR150 over the 250 Ninja for the same reasons (except for maybe the attractiveness )

[dave_boo]

Surely you could turn that argument on it's head and say that the Ninja 250R is a better touring bike than the CBR150 and a better bike for heavy Bangkok traffic than the ER6n/f?

It's sat directly between the 2 bikes in terms of price and performance so it just depends what you're looking for. When I was looking at trading up for the ER6f I decided against it because the plus side of an extra 40 kph top end and more overtaking power wasn't worth the negatives of the decreased range, another 110,000 baht, less manoeuvrability for my daily commute in Bangkok and (in my opinion) a less attractive bike. Others would choose a CBR150 over the 250 Ninja for the same reasons (except for maybe the attractiveness )

The Ninja has grown on me, but is it really much better than the ER-6* in traffic?

In reality everyone would have two bikes, a little 150 (or less) in town bike and a bigger 600+ for weekend rides.

[neverdie]

Surely you could turn that argument on it's head and say that the Ninja 250R is a better touring bike than the CBR150 and a better bike for heavy Bangkok traffic than the ER6n/f?

It's sat directly between the 2 bikes in terms of price and performance so it just depends what you're looking for. When I was looking at trading up for the ER6f I decided against it because the plus side of an extra 40 kph top end and more overtaking power wasn't worth the negatives of the decreased range, another 110,000 baht, less manoeuvrability for my daily commute in Bangkok and (in my opinion) a less attractive bike. Others would choose a CBR150 over the 250 Ninja for the same reasons (except for maybe the attractiveness )

The Ninja has grown on me, but is it really much better than the ER-6* in traffic?

In reality everyone would have two bikes, a little 150 (or less) in town bike and a bigger 600+ for weekend rides.

I knew I would convert you to my way of thinking dave.

[mixed]

Surely you could turn that argument on it's head and say that the Ninja 250R is a better touring bike than the CBR150 and a better bike for heavy Bangkok traffic than the ER6n/f?

It's sat directly between the 2 bikes in terms of price and performance so it just depends what you're looking for. When I was looking at trading up for the ER6f I decided against it because the plus side of an extra 40 kph top end and more overtaking power wasn't worth the negatives of the decreased range, another 110,000 baht, less manoeuvrability for my daily commute in Bangkok and (in my opinion) a less attractive bike. Others would choose a CBR150 over the 250 Ninja for the same reasons (except for maybe the attractiveness )

The Ninja has grown on me, but is it really much better than the ER-6* in traffic?

In reality everyone would have two bikes, a little 150 (or less) in town bike and a bigger 600+ for weekend rides.

To see whether the 250 is better than the 600 in traffic, just compare their width and weight.

See how the CBR is nice and narrow, that helps it slip thru the gaps.

[JonnyF]

Surely you could turn that argument on it's head and say that the Ninja 250R is a better touring bike than the CBR150 and a better bike for heavy Bangkok traffic than the ER6n/f?

It's sat directly between the 2 bikes in terms of price and performance so it just depends what you're looking for. When I was looking at trading up for the ER6f I decided against it because the plus side of an extra 40 kph top end and more overtaking power wasn't worth the negatives of the decreased range, another 110,000 baht, less manoeuvrability for my daily commute in Bangkok and (in my opinion) a less attractive bike. Others would choose a CBR150 over the 250 Ninja for the same reasons (except for maybe the attractiveness )

The Ninja has grown on me, but is it really much better than the ER-6* in traffic?

In reality everyone would have two bikes, a little 150 (or less) in town bike and a bigger 600+ for weekend rides.

I've not ridden the er6n/f, but it's wider, heavier and taller than the 250R so I'd imagine it's less agile in heavy traffic.

If I was buying again in the sub 250 range I'd buy a Raider 150, a good nimble bike for town and cheaper/more practical than the CBR150. Quite difficult to get a good one though...

[dave_boo]

To see whether the 250 is better than the 600 in traffic, just compare their width and weight.

See how the CBR is nice and narrow, that helps it slip thru the gaps.

Well, the 650 is 200 kg (204 with ABS) and 760 mm wide. The 250 is 169 kg and 715 mm wide.

Does 45 mm really make that much of a difference? Granted the 31 kg difference is huge, but is that not offset by the different seating position and increased leverage?

These are honest questions since I've not ridden the bigger bike....

[Richard-BKK]

The Kawasaki Ninja 250R compared to the Suzuki Raider R 150 and Honda CBR150...

Raider R 150 = 652mm width

CBR150R = 652mm width

Difference of only 63mm or 2.48 inch...

The two 150's have less acceleration power and less braking power and both are not available in Thailand next year.

[BigBikeBKK]

To see whether the 250 is better than the 600 in traffic, just compare their width and weight.

See how the CBR is nice and narrow, that helps it slip thru the gaps.

Well, the 650 is 200 kg (204 with ABS) and 760 mm wide. The 250 is 169 kg and 715 mm wide.

Does 45 mm really make that much of a difference? Granted the 31 kg difference is huge, but is that not offset by the different seating position and increased leverage?

These are honest questions since I've not ridden the bigger bike....

Well, the widest points on the Ninja 250R and Ninja 650R are the mirrors, so naturally if you plan to do a lot of city riding it might be a good idea to either fold them in or replace/remove them. Once you do that I don't know how wide the bikes are, but I've owned both and they feel about the same width to me. The featherlight Ninja 250R is very easy to throw around while the heavier 650s can require a bit more work. Actually the ER6n was the easiest for me in traffic- the mirrors are mounted up on the handlebars so they clear most car mirrors and I shortened the handlebars on my ER6n by about 2 inches to make it easier to squeeze through tight spots. Beefier suspension and greater clearance on the ER6n with belly pan removed made it easy to hop curbs too.

[BigBikeBKK]

Where have all the Ninja 250R riders gone? Perhaps everyone moved up to bigger bikes...

Anyway- came across some nice Ninjette porn that I thought some of you might enjoy-

Ride On!

Tony

[thaicbr]

oooooo...... i likey those twin tail pipes.....sexy.

Tony. do any of your contacts know where they came from?

[Jake1]

I just put mine up for sale today and I'm sad to say it but it is not for a bigger bike

2010 Special Edition can be found in the for sale section

[Hili]

I want to asked if its possible to make the Ninja naked, similar as ER6-n. Wanna start with a bigger bike than a scooter but i dont like the racing looks much. I think its possible for sure but will it be a big act? Maybe anybody tried/ seen yet? Thanks

Hili

[BigBikeBKK]

I want to asked if its possible to make the Ninja naked, similar as ER6-n. Wanna start with a bigger bike than a scooter but i dont like the racing looks much. I think its possible for sure but will it be a big act? Maybe anybody tried/ seen yet? Thanks

Hili

Sure you CAN take off all of the fairings and run the Ninjette naked, but she's quite an ugly duckling without her clothes on...

Ride On!

Tony

[Hili]

Yep Tony thanks, as iam seeing this.... not that nice. I imagined something like that..... but need to find fairings and headlights

[dave_boo]

So, those that know me know that I love the hypothetical side of motorcycling (engineering/mathematical). And I found a pretty cool site researching some things. I decided that since this thread had gone so stale I was going to liven it up with some information.

First thing I thought of was that I needed to get more HP out of the little Ninja (and actually who doesn't). 35 BHP (29.75 RWHP if we're to assume 85% efficiency through the drivetrain—more than the reported BHP!) sounded good to me so that's the base I started with. Running that through this page , I found out that getting 35 HP from a 2 cylinder engine was going to require an airflow of 57.88 CFM (1 639 L/M).Now since the engine is just a big air pump we have to make sure that the air goes in and out correctly to reach that. We also have to decide where we want our power. Unfortunately for us, it is pretty much decided; we're riding a sports bike of small displacement with pretty much set port diameter(cross section)/length. However, using the “Calculate Optimum Runner Size and Length“ calculator on this page we can get an idea as to whether or not the Ninja will support the airflow. Surprise, surprise; at the same RPM that the bike makes max torque it appears that the throttle bodies are some 28% bigger than required to support the torque that it is outputting. Going back up to the “Calculate Peak Torque RPM” and using the same hypothetical 24.7 mm throttle openings (what the current torque points to) nets a Peak Torque RPM of 8600 RPM, evidence seemingly bourne out by perusal of various dyno charts floating around the net (although not by Kawasaki's figures). Sticking with the same calculator, plugging in the values for the 28mm throttle bodies results in a peak torque at 11 000 RPM.

There is a fly in the ointment however (actually several), using the throttle body (mainly because I can't find accurate dimensions of anything else) is misleading in that you actually don't get all 28 mm due to the various restrictions. Add in turbulence and I'm going to pull a percentage out of my yoohoo and say that we're probably only looking at 85% of available volume. I.E. the value we should be using is for a 25.2 mm throttle body blade and ignoring restrictions there and further down the tract (only .5 mm bigger than what the engine's current torque suggests it has!). The good news is that using an intake diameter of 25.2 does move our Peak Torque RPM up to 8 970 RPM, nearly 800 RPM higher than what the engine currently make it at (based on Kawasaki's figures). From now on I'll be using the assumption that the total available diameter is 25.2 and basing my calculations on that. What's weird about that is according to this page Throttle Blade diameter should be .99 inches (drumroll.....25.15 mm)! So it seems that my guesstimation and Kawasaki's engineering are pretty close to each other (in that they installed a throttle body that was within 0.05 mm of what I assumed would be maximum efficiency....using 1 significant digit means I was on the money). However, we're still going to have to increase our torque a lot; according to Kawasaki England the Ninja puts out 22 Nm of force at 8 200 RPM (16.22 foot pounds and interesting in that at that RPM and torque you should be putting out 25.3 BHP). The reported figure of 22 kW (29.5 HP) at 11 000 RPM results in a 14.1 foot pound rating. All not good when we want 16.7 foot pounds at 11 000 RPM to reach our 35 BHP.

None the less, the bike is not making peak power, and as shown above there's a restriction somewhere in the system. One thing I considered was the cams; I found the following on the internet:

Valve Timing:

Inlet

Open 36° BTDC

Close 56° ABDC

Duration 272°

Exhaust

Open 61° BBDC

Close 31° ATDC

Duration 272°

From that I concluded that it has 67° of overlap and both Intake/Exhaust have a duration of 272°. Increasing the amount of overlap could give a boost to the peak RPM (of course at the risk of lower end performance), however AFAIK the cams are not so easily adjustable. If I were able (working overseas means whilst I can order adjustable cam thingies my time home is valuable and I'm looking for the quick fix) I'd definitely move the Exhaust to a 58° BBDC and a 34° ATDC. That would bring the overlap to 70° (and definitely make sure the exhaust was up to the challenge of removing those gasses would be a priority) and move the cam's centerlines withing 2° of 100° on each end (actually allowing more time for the exhaust to push against the piston for an additional 3° before being, well, exhausted).

Since I can't (won't?) mess with the cams I'm actually going to move on to the part that luckily for us is cheap and easy here in LOS (and what a reply on another thread got me investigating this); the exhaust. Unfortunately, the exhaust is designed with Euro III (?) standards in mind. Two catalytic converters and a diameter of only ? with a total of three bends before the the collector don't spell good things for me. My rough measurements of the lengths are as such; approximately 16 inches for the primaries and something around 6 inches for the collector (measured to the first catalytic converter). Running the numbers through this calculator it tells me the following:

Primary Tube Length is 18.18 inches (461.8 mm)

Primary Tube Diameter is 0.48 inches (12.19 mm)

Collector Length is 9.09 inches (230.9 mm)

Collector Diameter is 0.92 inches (23.37)

Since tubing doesn't come in those sizes (that I know of), I took the liberty of assuming 0.5 inch I.D. (12.7 mm) for the primaries and 1.0 inch for the collector. A total volume of 3.29 cubic inches (53.91 mm³) for the recommend values means that using the aforementioned 0.5 inch I.D. Tubing means that you'd need a primary length of 16.75 inches (425.4 mm). The collector's recommended total volume is 6.05 cubic inches (99.14 mm³) suggests that using a 1.0 inch I.D. Tubing necessitates a 7.693 inch length (195.4 mm). However, my knowledge of the effects of changing the size to something 4% and 7% larger, respectively, on the scavenging of the gasses is a bit low. However, solely looking at the volume (and assuming a 0.5 inch diameter) the volume of the stock primary is only 95% of what the calculator recommends. It is my understanding though that after the collector, you're pretty much free to do as you want as far as size/length goes. Get a big old stepped pipe (1 inch to whatever) and whichever exhaust gives you a tickle in the pickle and you should be good to go.

I'll keep researching this (specifically the affect of bends on the flow) and try and get a better answer; perhaps a math-y/engineering-y person could chime in and keep us going?

[thaicbr]

ummmm Thanks Dave. But why don't ya just buy an exhaust from sportisa or one of the myriad other factorys that have done the math and the dyno runs to get the best exhaust. also note about back pressure i'm pretty sure that you need a bit of back pressure or you lose the low and midrange. could be wrong though.

Also the max i have seen for the ninja250 was 32.5hp on a carbed bike in the states (note not a road going bike but a speed trial bike)

Edited June 7, 2010 by thaicbr

[dave_boo]

ummmm Thanks Dave. But why don't ya just buy an exhaust from sportisa or one of the myriad other factorys that have done the math and the dyno runs to get the best exhaust. also note about back pressure i'm pretty sure that you need a bit of back pressure or you lose the low and midrange. could be wrong though.

Also the max i have seen for the ninja250 was 32.5hp on a carbed bike in the states (note not a road going bike but a speed trial bike)

Because it was more an exercise in doing something (raining here and I'm bored out of my mind) and a way of getting the thread going again. And I know you've ridden a stock Ninja; low/mid torque, while ok, aren't really where the fun is at and could easily be missed. Note that from my (perhaps flawed) calculations I'm not suggesting a radical change so I don't think there'd be too much of a downer on the party there.

Actually, if I remember the bike you're talking about, they had quite a bit of modding in it; higher compression pistons, valve work, low friction drive chains, etc. Even if we're to think that they got 90% efficiency out of the driveline they still got 36 BHP(although I doubt the low drag chain made much of a difference; perhaps 85% is more like it and they had 38 BHP?)...perhaps I am being too optimistic.

[monkeyofdoom]

I thought I'd show this picture of the Two Bros full system I had installed last weekend. Only paid 400 baht to Kawasaki dealer here in Chiang Mai, including fitting and welding the bung for the O2 sensor. I thought that was a great deal. The price for the exhaust is another matter entirely :-/

[dave_boo]

By the way, what is everyone getting for fuel usage? Went tooling around yesterday at 80 or so just enjoying the views and during a break in the sonne thoke today decide to refuel as the light hadn't come on (why couldn't they install a fuel gauge like American models have?) and I was getting up there in mileage. A fill up of 9.8L at 320 km...32.7 km/L seems high doesn't it?

[BigBikeBKK]

By the way, what is everyone getting for fuel usage? Went tooling around yesterday at 80 or so just enjoying the views and during a break in the sonne thoke today decide to refuel as the light hadn't come on (why couldn't they install a fuel gauge like American models have?) and I was getting up there in mileage. A fill up of 9.8L at 320 km...32.7 km/L seems high doesn't it?

I used to get about 300km/tank on my old Ninjette, but that was with the throttle pinned most of the time.

I'm happy the Thai Ninjette has a temp gauge instead of a fuel gauge...

[JonnyF]

By the way, what is everyone getting for fuel usage? Went tooling around yesterday at 80 or so just enjoying the views and during a break in the sonne thoke today decide to refuel as the light hadn't come on (why couldn't they install a fuel gauge like American models have?) and I was getting up there in mileage. A fill up of 9.8L at 320 km...32.7 km/L seems high doesn't it?

I'm getting about 25 km/l now but a lot of that riding is either in Bangkok traffic or with a pillion. It's improved slightly as the bikes continued to break itself in. It's done about 15,xxx kms now and the gearbox feels a lot smoother now as well.

[dave_boo]

I used to get about 300km/tank on my old Ninjette, but that was with the throttle pinned most of the time.

I'm happy the Thai Ninjette has a temp gauge instead of a fuel gauge...

Why are you happy? What did the fuel gauge offer you? I hardly ever look at it; the heat on my right leg is the only reason that I'd look down at it....

I'm getting about 25 km/l now but a lot of that riding is either in Bangkok traffic or with a pillion. It's improved slightly as the bikes continued to break itself in. It's done about 15,xxx kms now and the gearbox feels a lot smoother now as well.

Well, than you have 50% more km on yours than I do; but I also never ride 2 up and never in BKK.....

[BigBikeBKK]

I used to get about 300km/tank on my old Ninjette, but that was with the throttle pinned most of the time.

I'm happy the Thai Ninjette has a temp gauge instead of a fuel gauge...

Why are you happy? What did the fuel gauge offer you? I hardly ever look at it; the heat on my right leg is the only reason that I'd look down at it....

Hi Dave, I think you mean Temp Gauge?

In the grand scheme of things it's not such a big deal one way or the other but personally I like to have a temp gauge so I know how hot my bike is running. That's what they are for after all.

I've heard a few reports of broken / malfunctioning cooling fans on Ninjette's. I find it reassuring to be able to keep an eye on the temp when riding in hot traffic or other hot conditions.

As for the lack of a fuel gauge, well, there is a fuel light. You never have to worry about running out of gas since you know you can always get at least 300km/tank.

Ride On!

Tony

[dave_boo]

Hi Dave, I think you mean Temp Gauge?

In the grand scheme of things it's not such a big deal one way or the other but personally I like to have a temp gauge so I know how hot my bike is running. That's what they are for after all.

I've heard a few reports of broken / malfunctioning cooling fans on Ninjette's. I find it reassuring to be able to keep an eye on the temp when riding in hot traffic or other hot conditions.

As for the lack of a fuel gauge, well, there is a fuel light. You never have to worry about running out of gas since you know you can always get at least 300km/tank.

Ride On!

Tony

Yeah, yeah, bust my chops because of an error.....I guess my biggest thing is that I've never had anything that didn't have a fuel gauge (ummh, I take that back-kinda-I don't remember if that Polaris quad did or didn't) and it just bothers me^tm. And with the fan; I've only ever seen it questionable when stopped for a long period of time here recently; even then it didn't get outside the middle bracket thingie.....

Personal preference and all that, but sometimes I forget to reset the trip odometer and then what am I supposed to do about knowing to fuel up in the next 20 km or so (which could be a problem finding where I'm at)?

[Newguy70]

Hi Guys,

Just picked up my bike a few days ago, and loving every minute of it. I have noticed it does run a little hot on the gauge 3/4 ways up, then again that could be due to the amount of downshifting I do as well. The exhaust is a little on the quiet side, any suggestions on where I can pick up the two brothers exhaust at a reasonable price (Not double the price!), or somethng similiar that one may have on his bike now that sounds better than the stock.

Thnx Guys

[koratsteve]

Can anybody tell me the price of the rear tyre for the Ninja 250 I need to know the dealer price for the standard IRC 130 70 H17, Thanks in advance.

[thaicbr]

OK any one still got a Ninja 250 here on TV. I'm actually thinking of getting one again for various reasons, What tyres are you using, any one have the Thai made DBS exhaust fitted (its nice and cheap at 7,000b for a full system) Any complaints about the bike, any revelations.

Thanks Allan

[JonnyF]

I've still got mine, done 16,xxx kms on it and no issues so far other than it kept blowing tail light bulbs which Kawasaki fixed at the first attempt.

I switched to Pirelli Sport Demons and they're good tyres, sticky and they're lasting very well. Going up to 140 on the back stabilised it a bit as it was a bit unsteady on a windy day over 120kph before that, much better now. Not sure about the exhaust you mentioned, I've got the Area P Carbon full system on mine and it sounds good, the stock exhaust sounds terrible IMO.

It does about 350kms on a tank. It's quite upright so it can be a bit tiring on long tours (over 500kms a day gives me a sore neck on this bike) but it's very easy to ride in the city.

I'll probably be selling it in a couple of months as I've got the gsxr now so if you're still interested in a couple of months you can give it a test ride.

[thaicbr]

I've still got mine, done 16,xxx kms on it and no issues so far other than it kept blowing tail light bulbs which Kawasaki fixed at the first attempt.

I switched to Pirelli Sport Demons and they're good tyres, sticky and they're lasting very well. Going up to 140 on the back stabilised it a bit as it was a bit unsteady on a windy day over 120kph before that, much better now. Not sure about the exhaust you mentioned, I've got the Area P Carbon full system on mine and it sounds good, the stock exhaust sounds terrible IMO.

It does about 350kms on a tank. It's quite upright so it can be a bit tiring on long tours (over 500kms a day gives me a sore neck on this bike) but it's very easy to ride in the city.

I'll probably be selling it in a couple of months as I've got the gsxr now so if you're still interested in a couple of months you can give it a test ride.

I have the Pirelli on the front of my current bike and quite happy with it. The DBS is kinda like the AreaP. The Thai builder said the AP was what he was trying to match. Yoi can get a touring screen for the 250 i saw it on the ninja250 thailand forum