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’08 Ninja 250: 3rd Day Riding “Real World Impressions” (Looking for “Nits”)

Gary J

New member
Joined
Nov 29, 2002
Location
South Bay
Moto(s)
Street & Track
Name
Gary
Having put two solid rides in on the new “08 Ninja 250, over the last two evenings, and put to paper (and posted on the forums) the highlights of my impressions of the bike …. I realized that I’d pretty much exhausted the discovery process in identifying all of the “good” (or great in many cases) aspects of the bike. Recognizing that there’s nothing perfect in the real world, including motorcycles, I decided to dedicate yesterday’s ride to the process of looking beyond the sunshine and blue skies of taking ownership and riding a new bike ….. and focus all my attention on digging deep beneath the shiny new paint, and looking to identify the “nits”.

Being a budget-priced bike, there’s no question that some compromises needed to be made when Kawasaki was going to the parts bin to spec out individual components for the ’08 Ninja 250. That’s the reality of life. You can only get so much, for so much money. Cartridge forks, fully adjustable shock, and complex computer controlled fuel injection systems just don’t come cheap.

In keeping with the easy-to-digest “itemized by category” format of the earlier postings, for providing real world riding impression feedback, I’ll use that method for sharing the results of the “nits finding” mission from today’s ride. For those interested, please reference the following:

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ENGINE: (Carburetion)

During the bulk of the 50+ miles that I put on the bike this evening, the riding was done while carving up some lightly traveled twisty backroads. Thanks to the open roads, the majority of those miles were spent at a moderately “spirited” pace, with the engine working mostly in the 7-10K range. In this mid-upper RPM range the fuel delivery, and resultant throttle response, had proven to be quite good. As a result, I had begun to come to the impression that all was rosy in the world of the carbureted USA model of the ’08 Ninja 250.

Normally getting stuck following traffic at a significantly sub-speed limit pace isn’t a good experience. However on the last few miles of yesterday’s ride, while on the last leg coming home, being subjected to this kind of riding environment proved to be a very valuable experience in the quest for uncovering the “nits” of the new bike.

This “nit” appears in the form of a “hiccup” (momentary power lag, followed by a snatch as it kicks in again) when going from total off-throttle position, to just cracking the throttle back on again …… in approximately the 4,500 – 6,000 RPM range …… especially noticeable in the lower (3rd/4th, etc) gears. While following closely being a train of cars in front of me (at around 30-35 MPH), every time they would go through their unexpected cycle of slowing and speeding up again, and I was forced to go to zero throttle and then come back into it again, I’d get a momentary “snatch” as if the bike lost fuel, and then had it turned back on again like a light switch.

No matter how smooth I was on the throttle movement, as long as going all the way to zero throttle position was part of the off/on sequence (while in this RPM range), I’d get the “snatch”.

I experimented and found a work-around, which was to consciously keep just a small amount of throttle opening during those moments I was needing to slow for the traffic, and work the brakes slightly against the very light throttle to achieving the needed slowing. By keeping the carburetors off of their total zero idle circuits, and minimal butterfly/slide opening positions, it seemed to avoid this “bad spot”.

I suspect that the reason for this behavior can be traced back to the testing processes used by the government regulatory agencies for meeting the current strict level of emissions outputs that the bike had to meet for 2008. Likely the carburetors are setup extremely “lean” in that specific RPM range, as a necessity in meeting those standards. The penalty for that compliance being the stock bike exhibiting this “nit” for new owners.

Not a big deal, and likely can be addressed by creative carburetion tweaks …. but a “nit” none the less that should be noted in the effort of trying to provide an un-biased account of the bike for those potentially considering ownership.

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SUSPENSION: (Damping Rates/Behavior)

- Compression/Springs:

I’d previously noted that both ends of the bike’s suspension has an extremely “firmer” feel to it, especially in comparison to the previous generation Ninja 250’s. This “firmness” is a welcome characteristic when the bike is being ridden in a spirited fashion …. at times when the road surface is not excessively rough, bumpy, or in overall poor condition.. That’s the “perk” side of this.

The “nit” side is that this “firmness” in the compression direction (spring preload, spring rates, high-speed compression damping) definitely makes the bike less happy when the roads get bad. The behavior materializes in the form of having the tires prone to “skittering” (momentarily losing, and regaining, traction) over really rough pavement. The more conservatively the pilot is riding the bike, the more noticeable (and more of a “nit”) this behavior will be.

This will be more of a factor for less experienced riders, where the previous generation Ninja 250 had a bit like a “comfy couch” feel (due to really squishy/soft suspension). The behavior associated with this aspect of the suspension on the ’08 model will be something they’ll see when riding on real world roads.



- Rebound Damping:

This was an area where the previous generation Ninja 250 was SERIOUSLY lacking; at least the front forks. A “pogo-stick” was the best way to describe how the stock forks on the earlier bikes performed.

It’s great to see that this historic, nearly non-existent rebound damping has been addressed by Kawasaki in the ’08 model. Unfortunately the budget price of the bike didn’t allow for the use of modern technology style suspenders. As result, the Engineers had to accomplish the additional damping using limited tools. The outcome is that the old-school “damping rod” style suspension is still WAY better then the old bike ….. but not without “nits”.

Statically testing the rebound damping in the garage, when I’d first got the bike, had already showed me that the amount (non-user adjustable) of damping (how slow it bounces back up) was slower then I would have preferred. The forks actually weren’t too far off, being pretty close to where I’d want them to be if I had an adjuster to turn. The rear shock was the primary culprit in this “too much damping” category.

It should be noted that my bike has less then 200 miles on the odometer, so things are still in the process of “breaking in”. It’s possible that the shock’s rebound damping may loosen up a bit once it’s got more miles on it? We’ll just have to wait-n-see.

Recognizing this “too much rebound” characteristic of the suspension, and consciously keeping it in mind while out on the road test riding the bike, I anticipated areas on the road where I’d likely see the impact. The places where it ultimately surfaced in the most recognizable form, was when taking a few corners that were located at the crest of “uphill” rises. I found that the rear tire wanted to get a bit “light” (lose grip with the pavement) at those moments.

This was due to the unweighting effects of the pavement surface dropping away over the crest, and the rear shock not responding quickly enough to cause the swingarm to drop down at a rate where the rear tire would maintain maximum grip ….. in tracking with the road surface.

It should be noted that it took riding the bike at what would be considered a VERY spirited pace (not top speed, but just cornering level for the tight/narrow backroads) in these spots, for a significant enough impact of the excessive rebound damping of the rear shock to become a fully recognizable event. Though the rebound damping is definitely not without flaw on either end of the bike (what you pay, is what you get typically, when it comes to suspension), I suspect that during the level of riding that most owners will do with the little Ninja 250, it won’t be greatly noticed while out on the road.

GENERAL – FUEL ECONOMY:

Prior to taking off on last night’s ride, I deliberately “topped off” the gas tank. The goal being to be able to get an initial feel for the fuel usage (MPG) of the ’08 model bike. The ride consisted of a mixture of approximately the following:

  • - 80% “Spirited” tight/twisty backroad riding (7-10K range)
    - 20% city street in-traffic riding

In topping off the gas tank again (from a gas jug), upon arriving at home, the bike took right around 1 gallon to bring back to the pre-ride level. With the ride being about 55 miles today, it worked out easy to see the approximate average mileage (55 MPG) the bike had returned on this mixture of riding. As is so often said ….. “your mileage may vary”.

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CONCLUSION – DAY 3 – “Nit Hunting”

The limited number of items that surfaced, despite this being a very deliberate “nit hunting” mission, shone well on the ’08 Ninja 250. A pretty small list, from a $3,500 motorcycle?

Hopefully digging out these “nits” from the recent real world riding experiences with this new bike, and posting them up on the forum will be of some value for other potential owners (or eventual owners).

Gary J
 
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So are we going to get to see you blasting the new 250 up hwy 9 or down the track?
 
So are we going to get to see you blasting the new 250 up hwy 9 or down the track?
A little green for the street and a little green on the track ...... will likely be the plan Josh. Look forward to doing some riding with you with the new bike, on another group ride soon. :thumbup
 
Interesting that despite the intake and presumed cam changes they couldn't exorcise that 4500-6000 glitch that was also somewhat prevalent in the prior generation, and that it is more pronounced. :| Seeing as how a LOT of new riders will be in that range for a bit perhaps it was just overlooked? Hmmph. :x

Gary, some carb info for you, when you get to tinkering (posted as seen stock from a ninja250.org admin on his new bike):

2008 Carburetor Info:
Make, Type: Keihin, CVK30(x2)
Main Jet: #98
Optional Main Jet: #92, 95, 100, 102
Main Air Jet: #100
Jet Needle: #L: N9VU, #R: N9VW
Needle Jet: #6
Pilot Jet: #38
Pilot Air Jet: #100
Starter Jet: #48
Pilot Screws: #L: 2 1/2, #R: 1 3/4 (turns out 360*)
Throttle Valve: 11* 00'
Idle Speed: 1,300 +/- 50 RPMs
Carburetor Synchronization Vacuum: Less than 2.7 kPa ( 2cm Hg) difference between two carburetors.
Service Fuel Level: 0.5 +/- 1mm (0.02 +/- 0.04in) above the mating surface of carburetor float bowl.
Float Height: 17 +/- 2mm (0.67 +/- 0.08in).

Regarding the skittishness, were you still running the 25/25 tire pressures or something different?

cheers,

-jim
 
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Regarding the skittishness, were you still running the 25/25 tire pressures or something different?
Thanks for sharing the carb spec info Jim. Much appreciated! :thumbup

By "Skittishness", I assume you're referring to the observation I'd had about the "firm" suspension (compression damping, spring preload/rate, and technology - "damping rod") producing a behavior where the tires tended to chatter a bit in contact with the pavement ........ when the road surface was bad/broken, and the bike was being ridden in a more average/conservative manner-pace?

If that's the reference you're asking about, here's some feedback.

Reducing the tire pressures from the original numbers I'd started with on my first ride (around 28 PSI - cold), down to the 25 PSI (front and rear) that I ran on my 2nd and 3rd rides (and still have in today), did provide a bit of a band-aid.

I definitely noticed that the softer tire (more sidewall "flex") helped reduce the sharpness of the vibrations, and improved the tire's bite, in those instances where the chassis wasn't totally happy (due to the suspension response).

As that the bike is quite light (compared to 600cc+ machines), and tire pressures are very much linked to the total overall weight they are carrying, I may continue to experiment with dropping pressures in very small increments, and then evaluate all aspects of the impact on the bike's performance on the road.

Basically experimenting with tire pressure in this case, will be similar to the process used in making suspension adjustments. You keep going in one direction for any adjustment, as long as the performance continues to "get better". This is continued to the point where going in that direction results in the performance just beginning to "get worse". Backing up one step should put things into the "sweet spot".

The first oil change will be tonight, after which I hope to put in a lot more miles of backroad riding/testing this weekend. Should have lots of opportunity to continue to bond with the new bike, and experiment around with little things like this. The goal being to be able weed out some secrets that other owners of the '08 machine might ulitmately benefit from, in not having to go through the same trial/errors learning curve.

For anyone that hasn't bored of the topic of the '08 Ninja 250 ...... and wishes to get more feedback .... please stay tuned. :)

Gary J
 
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very informative, and much appreciated! :thumbup

Have a great :ride this weekend!
 
Gary,
If you've been on 85 north of 280, how's the syspension handling that road surface?

If ever there was a road surface to check out the low-speed workings of the suspension, that's it...
 
Gary -

That carburetion glitch you're feeling around 6k revs isn't unique to your bike; mine feels the exact same way. Going up through 6k it feels like a bit of a flat spot, but the interesting part is that going down through 6k when decelerating there is a bit of a burble/cough/stutter from the engine. Happens every time. It's so predictable, in fact, that it feels more like some weird programming on a fuel injected bike rather than a carbed bike; I don't know what mechanism can be causing the behavior so reliably. As you say above, it's a nit, and certainly not a big problem in any way.

As you said in one of your portions of the review, YMMV. Mine certainly does, I was able to get it down to 35 mpg on a trip through Mt. Hamilton & Mines. On today's loop ride, with a combination of twisties, goat, and freeway, I got 40.5 mpg. I doubt our bikes are tuned differently, but I'm probably, uh, less aerodynamic than yourself. :laughing
 
On a bike this small in mass, weight, and displacement rider weight and dimensions certainly can make a difference in mpg.
 
great ride up... i want one of these bikes. hopefully i can find a crashed one.
 
I was able to get it down to 35 mpg on a trip through Mt. Hamilton & Mines. On today's loop ride, with a combination of twisties, goat, and freeway, I got 40.5 mpg. I doubt our bikes are tuned differently, but I'm probably, uh, less aerodynamic than yourself. :laughing
The good news is that I'm still loving every minute of riding my '08 Ninja 250 ...... as much as I did at the first ride, after close to two months (?) having passed since I wrote the first Test Ride report here on the forum. :thumbup

Got a few minutes, so in seeing a few folks stir the pot of interest on discussing the bike again, figured I'd jot down a few subsequent post-ownership impressions, FWIW.

- MILEAGE:

That seems really odd Alex, that your bike would get that low of a mileage reading (35MPG}, no matter the circumstances with rider size/weight, etc?

The venue that my '08 Ninja 250 has primarily been ridden during the 3,200 miles it's seen so far, are the twisty backroads in the SC mountains. The bike's seen very limited freeway use, so I've not had a lot of exposure to those peak MPG numbers that a constant cruising would likely produce. However the mileage numbers I've seen on my bike, over the 15+ fill-ups of gas that have come and gone so far, are as follows:

  • - Highest mileage: approx 55 MPG (moderate RPM, early shifting, easy-riding, during break-in)

    - Lowest mileage: approx 43 MPG (VERY "spirited", upper-RPM, lower gear, tight road, canyon carving)

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- LONGER-TERM OWNERSHIP OBSERVATIONS:

- Fuel gauge:

The fuel gauge on my bike has proven to be pretty far off from accurately mapping out the level of gas in the bike, and rate of usage while riding. The two primary observations of it's performance are:

1) The gauge doesn't want to ever go all the way to the "F" (Full) line, unless you almost fill it up to the point that the gas would be all the way up to the top of the filler neck, at cap level.

2) The rate the gauge goes down does not track linearly with the fuel usage.

The bike will show a "1/2 Full" level, after the bike has only really used up less then 1.5 gallons, in a tank that actually holds 4.8 gallons total.

When the gauge gets all the way down to the last "E" (Empty) line, the bike actually has over a full gallon of fuel remaining, and can do at least another 50 miles.

As a result of these experiences, I've come to the opinion that I miss the crude ...... but reliable, "1 gallon remaining" manual petcock of the old Ninja 250. Once it was called into play while riding, the remaining miles left till needing gas was quite consistent, and easy to determine. Oh well, just a small "nit"; where once you've learned to compensate for the "indicated" fuel level, versus the "actual", it's no big deal.

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- TIRES:

As a pre-cursor, it should be acknowledged that the type of roads, and level of "spirit" that my '08 Ninja 250 has been almost exclusively used during the last 3,200 miles, is not exactly the norm for these bikes. As a result, the work asked of the tires is a reflection.

The bike has already seen 2 front tires, come and go. The first being the OEM Bridgestone BT45, and the second being a Dunlop D209GP "take-off", that had 90%+ of its wear remaining when it went on.

Out back, the bike is ready for its 3rd rear as well, with the current tire showing very little remaining tread as of this weekend. Below is the tire history, so far:

- Tire Wear/Mileage:

FRONT:

  • - Bridgestone BT45 (110/70/17, bias-ply): 1,300 miles (90% worn)
    - Dunlop D209GP (120/70/17, radial): 1,800 miles (90% worn)
    - Bridgestone BT090 (110/70/17, radial): --- nearly new ----

REAR:

  • - Bridgestone BT45 (130/70/17, bias-ply): changed @ 1,800 miles (w/50% tread remaining)
    - Dunlop Sportmax D208-SM (140/70/17, radial): 1,500 miles (95% worn)

Despite (or perhaps "because of") the low HP of the bike, the tire longevity seems to be a lot shorter then I'd have expected. The best explanation that I can come up with is that the combination of the firm suspension rates, less then high-tech damping technology, and the high level of confidence for really "tossing it" into the turns that the bike's chassis and light weight inspires, results in a lot of "scrubbing" (slip-angle) of the tires when ridden in a "spirited" fashion. This "scrubbing" resulting in a sandpaper effect that seems to gobble up rubber at a high rate. Again it should be noted that this bike is definitely "ridden" :wow and spends its life on some pretty abrasively paved backroads.

In the quest for not getting put into the poor house from the tire bill on this otherwise economical little bike, I've got a new "Plan "C" in mind as the next test of tire size/brand/model tire testing on the bike. Stay tuned on the outcome of that testing, in the next month or so, if you have an interest.

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There's a few more categories (brakes, chassis setup for tires size/type, etc.) of life in the Real World with the new '08 Ninja 250 that I've now had the opportunity to put into the books after 3,200 miles of use ...... but will have to wait for a few more free minutes in the near future, to put them down in writing on one of these treads. Once again, please stay tuned, if you have an interest ..... and let me know if you have any specific questions on the bike.

Happy riding all ........... :ride

Gary J
 
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