'06 Kawi Ninja 250r

[SHIFT_Z]

^ That would be my guess. Those bikes rev to like 14k don't they? You won't notice any more of a significant pull after about 10 - 11.5k, the torque band tapers off.. but it should be a considerate pull up till then. If it stops pulling after about 6 or 7k... somethings definitely off. Especially if this is happing in the lower 3 gears.

[PoorManQ45]

Alright, I adjusted it some more.

I found that the air/fuel mixture screws were set really rich. The guide says turn the screw in all the way, then back it out 2.5 turns. I'd say 2.0 turns is closer to where it should be.

Unfortunately I managed to strip one of the screw heads and the threads on the carb... Basically I used a screw driver that was slightly too big and I didn't notice it cutting the side walls.

So, I will be ordering a new set of carbs today or tomorrow. Luckily they're cheap.

I think that should fix everything.

[C-Kwik]

Changed it for fresh 93 octane. Can someone please explain why the manual and everyone recommends 87 octane in this engine? The compression ratio is 12.4:1. My quad at 11.7:1 will detonate with 87...

Compression is not the only factor when it comes to determining the necessary octane rating. Ignition and cam timing can change the peak pressures reached in the combustion chambers which is the primary factor for knock.

Something is definitely off with the carbs.

Double check for exhaust and intake leaks. Changes in airflow can make the jetting seem off. I had a small exhaust leak on a vulcan 500 (has a version of the 500r motor) and fixing that made a huge difference. Make sure the air filter is clean as well.

[PoorManQ45]

I'll check what you suggested.

Note: Adjusting the air/fuel screws as much as I could with the damage changed the behavior of the engine.

It responded better and wanted to idle, but I could only adjust one carb completely. So I'm really confident that the carbs are the issue.

But i'll check the intake and exhaust just to be sure.

[mmm240]

Order some bigger jets while you're at it! Get the most outta that little engine.

[PoorManQ45]

Bigger jets with everything stock won't do anything.

Now, there are a few other mods that can be done without changing jets.

Like putting a .025mm shim under the pilot jet needle. This will remove mid-rpm hesitation.

There are alot of cool little things that can be done on this bike.

I am thinking about getting rid of the stock airbox and going with pod filters. This will allow more room to work on the engine and a little extra storage space. Oh, and more air to the engine

[PoorManQ45]

Just ordered a replacement carburetor.

Also ordered a ZX600C shock. I noticed while riding it around last night that it is too soft in the rear. I am a little heavy for the bike anyways, and at times i'll have a passenger. The stocker definitely won't handle two people. Nothing like getting a shock for $30

[Ace2cool]

Damn, 250's are cheap!

[PoorManQ45]

Hehe, well it was the same bike with minimal changes from 1988 to 2007. So everything is interchangable

[PoorManQ45]

Well, got the carburetors in yesterday.

Cleaned and installed them.

Set the air/fuel screws both to 2 turns out.

Applied choke. Bike started right up. Turned choke off. It stayed running. It didn't stay running before. Adjusted the idle screw. It idles at 1.2k perfectly.

Good throttle response.

It starts to come alive at around 6k RPMS. Going from 9k to 12k is in the blink of an eye.

Second gear is perfect for low speed manuvering. First should only be used from a stop.

The front end gets light when power shifting in 1st, 2nd, and even 3rd! Might change the fork springs and add a cartridge emulator.

I think i'm going to order the 85/80 Osram headlight bulb.

Also, the stock windshield is useless. I might invest in a double bubble

[mmm240]

Cool! Most windshields are for aesthetic purpose. IIRC you stated that you were a "bigger guy" It's gonna be damn hard for you to tuck below that thing.

How's that rear spring working out?

[PoorManQ45]

I havent swapped the shock yet.

I figured I should ride around with the bike in good tune in stock form so I can appreciate the upgrade.

i was looking at DIY windscreens. Do you think a cruiser style shield would look too goofy on this bike?

[PoorManQ45]

Also, I'm not that big. 6'1" and ~205.

[mmm240]

Do you think a cruiser style shield would look too goofy on this bike?

I do, but if you really wanna rock behind a screen comfortably, go for it.

Do you wear a full face helmet? I do and limits my tucking needs to when I feel like it or it's ridiculously windy and cold. I ride in 40 degree weather.

[PoorManQ45]

I just added a little extra lighting to the rear end.

I put a 2357 bulb in the center brake light. This bulb is the same brightness on low, but brighter on high/brake.

Then I added a Conduct-Tite #85803 plug to each of the dummy pods next to the brake light. I put a 2397 in each one. The 2397 is a little dimmer then OEM on low, but brighter on high/brake. This gives more contrast between the two modes.

These should improve rear visibility a lot. This modification took about 30 minutes from start to finish.

Here is the walk through. http://faq.ninja250.org/wiki/I...ckets

You can use part #84725 for the sockets if you don't want to have to solder an extra wire on to the 85803.

I also purchased a Sylvania Xtravision 9003 bulb. These a +30 bulbs with no tinting. So it should be a little brighter. I haven't installed it yet.

[PoorManQ45]

Went for a ride last night.

The brake lights are noticeably brighter both on the ground and against a wall. My brother said they're almost blinding now whereas previously they were just "noticeable". This is what I was going for.

I think I will order one of those cheap flashers from ebay and make the pods flash. This will leave the center solid and flash the pods for ~4 seconds before they go solid.

This morning I took the carburetors back off. I set the air/fuel mixture to 1.75 turns. This removed the slight bogging that occurred between 2k and 4k RPMs.

I still haven't installed the zx600c shock. I'll probably do that tomorrow.

I've figured out that I'm just getting the bike back to where it should be with a few improvements.

I'm thinking of changing the front fork springs. The front end is way to soft and bottoms out hard when you brake hard. This should improve traction also as it will maintain more pressure on the front tire.

[C-Kwik]

Cool! Most windshields are for aesthetic purpose.

I'd say a lot of people buy them for aesthetic reasons, but altering the shape does change the way the air flows around it (for good or for bad). The f4i windshield for example, allowed a lot of wind to hit my chest at highway speeds. A puig double bubble solved that for me. The wind attacks some point on my helmet. The force isn't bad, but the wind noise went up quite a bit. Tucking in causes a "vortex" type of noise as well. I wear ear plugs so either case is not a big deal, but it is much more comfortable behind the double bubble.

I'm thinking of changing the front fork springs. The front end is way to soft and bottoms out hard when you brake hard. This should improve traction also as it will maintain more pressure on the front tire.

A stiffer fork spring does not, in that of itself, change the amount of pressure on the front tire. Weight transfer is a result of the center of mass still wanting to continue the same speed as you hit the brakes. The amount of weight nor your desire to stop/slow does not change so the weight transfer (thus the load on the front tire) does not change. There could be some minor change from the change in position of the center of mass with respect to the amount of stopping force applied, but it would be minor. What a stiffer spring will do in your case is prevent you from bottoming out which helps to provide more control under braking as road irregularities will be soaked up by the suspension allowing your tire to maintain good contact. Of course too stiff and you can also end up approaching almost like you are on no spring at all.

Another benefit is that it can help prevent nose diving which can provide a rather unsettling feeling under hard braking. But do make sure you also use enough rear brake. The rearward force on the bottom of the tire pulls on the swing arm and has a natural anti-lift property (some bikes do this better than others) at the rear which would help the bike feel like its not as likely to do a stoppie.

[PoorManQ45]

I'd say a lot of people buy them for aesthetic reasons, but altering the shape does change the way the air flows around it (for good or for bad). The f4i windshield for example, allowed a lot of wind to hit my chest at highway speeds. A puig double bubble solved that for me. The wind attacks some point on my helmet. The force isn't bad, but the wind noise went up quite a bit. Tucking in causes a "vortex" type of noise as well. I wear ear plugs so either case is not a big deal, but it is much more comfortable behind the double bubble.

I was thinking of getting a double bubble. The stock shield is there just for looks.it hits me in the chest with wind. It's also tinted. I don't like that. I want a clear shield.

A stiffer fork spring does not, in that of itself, change the amount of pressure on the front tire. Weight transfer is a result of the center of mass still wanting to continue the same speed as you hit the brakes. The amount of weight nor your desire to stop/slow does not change so the weight transfer (thus the load on the front tire) does not change. There could be some minor change from the change in position of the center of mass with respect to the amount of stopping force applied, but it would be minor. What a stiffer spring will do in your case is prevent you from bottoming out which helps to provide more control under braking as road irregularities will be soaked up by the suspension allowing your tire to maintain good contact. Of course too stiff and you can also end up approaching almost like you are on no spring at all.

Another benefit is that it can help prevent nose diving which can provide a rather unsettling feeling under hard braking. But do make sure you also use enough rear brake. The rearward force on the bottom of the tire pulls on the swing arm and has a natural anti-lift property (some bikes do this better than others) at the rear which would help the bike feel like its not as likely to do a stoppie.

Excellent points. I meant that the front tire should maintain better contact on rough roads. It is a very odd feeling with the front end diving hard. The bike doesn't just lower down when the front and rear brakes are applied.

That reminds me. I need to adjust the rear brakes. It takes too much movement to get them to engage. I like quick engagement. Might have to change the pads too.

[PoorManQ45]

last night I took the bike on the freeway. I got it up to 95 per the speedo. I was fully tucked. It felt like I was going to be ripped off the bike!

So today I ordered a slightly larger windscreen. 2" taller and 1" wider. It slopes a little bit less to the rear. This should give a huge improvement in the air pocket size.

I also ordered 0.75kg/mm Sonic Springs. I'm changing out the front fork springs. I'll probably go with a 7.5w oil instead of factory 15w. The reason for this is that the front end bottoms out under hard breaking. This causes a momentary loss in traction. To me this simply feels unsafe. The stock spring is 0.440kg/mm. This should be a big improvement.

[mmm240]

That's kinda odd that the wind was hitting you so hard to make you feel unsafe. What is fully tucked to you? To me, it's chin on the tank.

[PoorManQ45]

That's kinda odd that the wind was hitting you so hard to make you feel unsafe. What is fully tucked to you? To me, it's chin on the tank.

Yep. That's how I was.

You have to remember, this is a 250, and I am 6'1". So to tuck like that my back arches upwards a bit. I believe this is putting my back right at the edge of that airstream. That's causing lift.

[PoorManQ45]

Installed the new windshield last night. When I am sitting up at 45 the air hits about 6" higher on my chest.

I rode the bike to work today. About a 30 minute drive on the freeway. Doing between 70~90mph(per speedometer).

1: It's freaking cold.

2: Joints start to get stiff. I don't know if I could go much more then an hour at a time in prone position.

3: Sitting up at 80mph is a whipping experience.

4: The front end wanders and wobbles.

5: Overpass joints are bad for the first one, but the second one coming off the over pass is worse as there is usually a dip after it.

6: The engine is leaning out at ~5k~8k rpms. This causes a surging.

I intend to correct 4 and 6.

For 4 I will change the tires. Apparently the stock tread design causes wobbling and tracking. Also, the speedometer is up to 10% off with this tire size. I intend to go slightly larger on both front and rear. I'm thinking a dual compound with a hard center rib for freeway driving and soft edges for handling.

For 6 I will shim the main needle slightly. I'm thinking one or two #2 washers per needle should work perfectly.

[mmm240]

Manufacturers intentionally make the speedo show more than you're actual speed. I wouldn't change the tire size to fix this. They made the bike specific for that size. There is a product called the speedo healer if you are truly interested.

I went with a rather sticky BT016 Dual comp tire. They are pretty good, but be warned Bridgestones are notorious for taking a long time to heat up.

[PoorManQ45]

I was thinking BT45.

Remember, these are a 16" wheel. There are a total of like 7 tires for this bike... LOL

About the speedo, yes, it is geared 10% higher then actual speed. Increasing the front tire size slightly will correct this. I will increase the rear size to keep the balance of the bike. This should increase the steering angle slightly and improve cornering.

Remember, this bike was almost the same exact from 1988 through 2007. Check out the http://faq.ninja250.org/wiki/Main_Page . It's amazing. Basically anything you can think of, they have a guide for it.

[PoorManQ45]

Thank you for the input though. I don't mean to be dismissive of your help.

[PoorManQ45]

Oh yeah, I installed the rear shock over the weekend. I set the air bladder to 15psi and the damper to 3.

It is a good bet stiffer then stock, but not jarring.

With two people on the bike it no longer bottoms out on speed bumps! It rides almost perfectly with two people. It is very smooth.

Now I'm just waiting for the fork springs to come in.

[HashiriyaS14]

Yay to this thread.

I need to get the Ruckus extension done and then I'll start working on the 250.

[PoorManQ45]

I just adjusted the needles.

I put two #4 washers under each needle. This can be done without removing the carburetors. Took about 15 minutes.

I rode it around for awhile. The throttle response is much improved and the bogging at 30mph in 6th gear when accelerating is gone. It just speeds up now

I'll take it on the freeway to work today and then I'll see if the loss of power in the mid RPM range is gone.

My new Fork springs should be here today. I'll probably put them on this weekend.

I am hating the feel of the brakes. They work just fine, but they are squishy. I want a nice firm engagement.

First I'll bleed the brakes and tighten the levers, but I'm not sure that'll fix the issue completely. I might have to get some stainless steel lines and upgrade to sintered pads front and rear.

I still need to order tires.

I think once those things are done I will be finished with the bike and just enjoy it

[mmm240]

Yes to EBC sintered pads!

I don't think ss lines are necessary, but If you want to go all out...

[PoorManQ45]

Yep. EBC sintered for the front. They only make organic for the rear of the Ninja.

So I'll probably go with Vesrah or DP sintered for the rear. Unfortunately these are "only" GG friction pads. Whereas the fronts are HH. Shouldn't be too big of a deal in the rear.

Any other suggestions for the squishy brake lever feel? I'll adjust them a bit to see what happens. Then I'll change the fluid out. Anything else?