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Discussion Starter · #1 ·
On top of all the cosmetic work I will be performing on my bike, Ninjalina, I want to do a little tweaking as well performance wise. I've already mentioned upgrading to a slip on exhaust which will help out a little bit and also a sprocket change. As far as a significant increase in HP and Torque, I have a few options I would like to discuss. I have a source of getting a turbo for my bike, a NOS kit, and another option would be swapping a larger engine, such as a ninja 500 engine. I know none of these procedures will be easy and I also know that lots of other mechanical work must be done in order for any of this to work properly, BUT, anybody have any thoughts they would like to throw my way to help my decision making process easier?
 

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Don't do any. Turbo would not work nitrous will brake things and the 500 engine is to heavy . The 500 Ninja is not that great a bike . Just get a Tryumph 675. It looks the same as the 250 ninja from 100 feet away. The weight is close at under 400 lb . But the engine has 125 hp.That is more than you can ever get. Even a turbo 500 with nitrous would not be as fast.
 

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I agree with RX, Working the little Ninja to its peak performance is more fun than having tons of power. If you want tons of power go for a 2nd bike in the stable. One for the GO days and one( the Lil Ninja) for the Finesse days!!

I am height challanged, so many sport bikes are not even available to me. Is this the issue with you?
 

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Rachel,

my answer is pretty much the same as theirs... The thing is, if you have an extra 7K lying around you wanna do something cool with, pursue the options which you mentioned, but on the 250, there is just so little extra this bike has to give that as soon as you add something like a turbo, you have to build a WHOLE bunch of other things up to keep the bike from killing itself...
 

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You can't just add any of these things. The turbo is very complex issue . The engine has bearly enough exhaust to push the turbo fast enough to make enough boost. Nitrous is good till the bottle runs dry and you can't use stock pistons or pump gas and adding a 500 is not worth while. The 650 engine is better. But any of these options will push the speed past the suspension limit. The bike is inexpensive because it has 100mph worth of shocks and brakes.
 

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Discussion Starter · #6 ·
Racer, did you see my original post where I mentioned that I know full well that I can't just add any of these items? Just want to clear that up, that I am aware of that.
And yes Zartan, Im 5'3 and on my 250 I'm not even flat footed. I know you can get bikes lowered, but that messes with the suspension so I wouldn't have that done unless I upgraded to a bigger bike in the future and even then I'd be weary about it
 

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Good luck with whatever you choose to do, and by the sounds of it, you have a good idea of what is in front of you.
As Racer X mentioned, the 500 engine is heavy, and the 650R engine is actually more compact and better packaged than the 500.
 

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Awesome, well, sounds like you're pretty committed to this... So here's some help:

Brakes:
dual front disk brakes: Kawasaki Ninja 250R Street Fighter - YouTube
Also consider going to a bigger master cylinder/reservoir off of like a zx-6R

Suspension:
This I have not done any research on, but there are quite a few Thai 250's floating around with inverted forks - I have no idea which bikes they came off of, but with a little bit of searching, you should be able to figure it out.... Not sure how this is going to play with the dual disk conversion. In fact, I would actually start with this, maybe just take the completely front clip form a zx-6R or some other 600cc Super Sport.... But you're goal here is dual disks up front, inverted forks, and a fully adjustable rear-shock. Fully adjustable = preload, compression and dampening adjustments.... Up to this point, if you're smart, dilligent and frugal you could probably make everything happen for less than $3K

Once you have your brakes and suspension figured out, you can start building the engine to handle more power... The biggest factor to keep in mind would be the frame... Torque twists frames, so HP would be better - which means higher RPM's, and an overall louder bike....

BUT...

An engine swap is going to be the easiest in the long term.... If I were in your position, a 500cc with high-comp pistons should be cheapest/easiest to do.... Engine mounts and slight body modifications....

If you want to stick with 250cc to stay truer to the bike's design, and probably respect the frame a little more than the torque of a 500 would, here's a list of things you'll have to look into...

Strengthening the bottom end through gussets and re-engineered steel/brass bushings on the crank. New springs and possibly clutch plates because the 250's clutch only handles 40hp.... Unless you want to do a clutch at least once a year.... Possibly steel sleeves for the block - so bore the block and have the sleeves made.

Once the engine is prepped, here is a list of things to do to get more power:
port/polish/ flow the head
TI valves and better valve springs.
high-comp pistons (unless you turbo, in which case slightly lower comp but FORGED replacement pistons)
Swiss cheese the airbox - this is what I did to mine: http://www.newninja.com/forums/f98/i-just-cant-keep-my-grubby-little-hands-off-of-it-4190.html , or pods if you run a FI (forced induction)
convert to FI (fuel injection) - recommended for a turbo
full exhaust (completely custom with a turbo)
new cams/cam timing
ignition timing (BRT-TIS) - recommended for a turbo

And it would be best if you yank the lump from the bike and massage it on a bench for many months until it's just right before stuffing it back in the bike.... If you do most of this yourself, the engine probably won't cost you most than $4.5K, but you'll have upwards of 60hp, and hopefully it will run fairly reliably.

Hope this helps and sets you in the right direction.... And if you start doing this stuff, keep us posted, I'd LOVE to follow this project!
 

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Discussion Starter · #10 ·
Spooph, can't thank you enough for all the helpful information! I appreciate you taking the time to set me straight on a few things and get me moving in the right direction if I am going to pursue pretty much rebuilding my bike's engine. ;)
 

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My suggestion would be to first determine just how much performance you are looking for, then find a different cycle that reaches that performance level without major modifications.

Any of the mods listed take just as much skill to tune as they do to install. You will constantly be running up against the limits of stock engine internals - rods, cranks, clutches, etc, are all designed to support a certain power level. Going beyond that point will give you a catastrophic failure. You won't know how much is too much until you go past it.

If you like the little Ninja, you are best to do some basic mods like a slip-on or pipe and call it a day. Striving for any large increases in performance from the Ninja is an exceptionally expensive, time-consuming, and impractical venture - unless you are looking for 250cc speed records.

Racer-X can tell you exactly how difficult it can be to coax more performance out of it - he's been there/done that.


Jay
 

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You guys are funny! You are all acting/talking like upgrading horsepower/torque means you have to upgrade other stuff is a new concept or something...It's like that we any vehicle...

Seems to me like everyone is trying to scare her off from doing what she wants to do...
 

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You guys are funny! You are all acting/talking like upgrading horsepower/torque means you have to upgrade other stuff is a new concept or something...It's like that we any vehicle...

Seems to me like everyone is trying to scare her off from doing what she wants to do...
although your statement is true, the scale of investment vs. initial cost vs. yield is exorbitant when it comes to the 250....
 

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You guys are funny! You are all acting/talking like upgrading horsepower/torque means you have to upgrade other stuff is a new concept or something...It's like that we any vehicle...

Seems to me like everyone is trying to scare her off from doing what she wants to do...
Depends on how far you want to go - pistons, rods, cranks?

If a certain level of performance is a major factor, buy a cycle that delivers the level of performance you require unless you are bound by certain restrictions.

Small-tube frames, small forks, small rims, small brakes, etc are going to limit the levels of performance (and safety) when significantly modifying a cycle like the Ninja. If we are not talking about a significant power increase, that's a different story.

I'm not sure of her riding/wrenching experience, but some of us here have had racing and tuning experience and can attest to the difficulty of getting a major increase in power out of a small engine. Having the experience and knowledge to tune a modified engine is completely different from bolting things on in the right place.

I'm not sure she is familiar with all that is required to accomplish what she is considering - that's why we are discussing it.



Jay
 

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I agree spooph.

Jay, I know why we are discussing it...I am a gear head much like the rest of us here, I know what happens when you add a bunch of power and nothing else to control it...

I know you guys are just trying to help...
 

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Ok I see all of these people crushing the dream of turbo charging your 250. Do it! I did mine and don't regret it. First thing is you can not by Chinese junk! EBay turbos will make you regret going cheap. Buy a 600 is all I see on these threads. I am running .5 bar or 7 psi on stock internals with the ecotrons efi. Cost me about $1700 but I'm making 97 whp and sleep on 600s all day. The only problem I have is keeping a clutch in it. I can out ride any 600 in the corners and ride away on the strait away. Had to change my drive ratio to compensate for all the new power. Have a 15T front and 44T rear sprocket. To put the power down had to go up to a 150 tire. I will post picks soon. I am copy writing my design and plan on producing kits. I will post my dyno sheets tomorrow along with the video. Last thing if you do not have a strong mechanical background, have a professional build your project. It is not a weekend warrior deal, a lot of fabrication and substantial knowledge of turbo systems is needed. If you don't have these things lots of bad news is in your future. I build these for a living. Not to mention it is very difficult to tune your bike you will need a dyno and someone to tune it. The average person and a laptop at home will not get the job done. You will just blow it up.
 

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Outride a 600 through the twistys? I'd be up for that challenge if I was near you ;-) what suspending and brake settings do you have ?also 95 rwhp what's your torque figure ?my 6 has 116rwhp and doesn't weigh much more than your 250!
 

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Turbo, hate to rain on your parade, but you have re-opened an old zombie thread that has had no comment since October last year. Rachael has since moved onto a ZX6R.

We would be very keen to see the results of your claims especially the cost.
 

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HELLO Turbo
I am just getting the nitrous worked out. I am very interested in your kit. As for a clutch. I have a pretty good set up with Barnett carbon disc and VERY heavy springs. I think it will hold 60 to 70 of nitrous. But 90 That will cost about 1500 dollars to have a custom cover and basket built. 5 springs and a ZX6r clutch pack should hold.
 
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