Help with my Ninja powered Kart?

[christeeezy]

Hey Ninjette, so I have a friend who had an '88 ex250 that has just been sitting in his yard rotting away. I guess he had plans of rebuilding it back to riding condition, but he decided that the bike was messed up beyond repair (after looking at it, I agreed).

So, for a small price, I took the bike off his hands to try something different; I'm building a Ninja 250 powered shifter kart. (I feel some sort of bad juju coming to a Ninja forum to say I tore one apart lol...). Hopefully you guys are still friendly enough to help me out . Please keep in mind that I already have done a TON of Googling. These following questions are what I could find nothing on.

Firstly, karts normally have the fuel cell mounted on the floor pan underneath the steering column. Since the motor obviously normally had its gas tank above it, I'm assuming that the carburetors are gravity fed. Am I right? If so, does anyone know if there is a port on the carbs that would supply a pulse signal for a pulse fuel pump?

Secondly, is there a wiring diagram anywhere that's strictly for ignition? I would like to do away with all other electrical systems, and the full wiring schematic gives me headaches lol.

Also, I took the motor top end apart the inspect for damage. This means I had to remove the camshafts and cam chain. Is there a good guide for doing timing on our motor? And it turned out that one of the pistons were badly scored on the side. I've sourced an '05 motor with rod knock, will its top end (head, pistons, connecting rods) work on an '88 crankshaft and journal bearings? Conversely, will the '88 crank and journal bearings swap directly into the '05?

Also, I tried looking through the service manual, but couldn't figure it out. What is that one random electrical post above the transmission case for? It had two red wires soldered onto it and the wires were incased in black tubing to give the impression of one wire.

One more question. I've tried shifting the transmission through the gears just to see if it would. It seems that it wont go past 1st, or neutral. I googled the problem and read that some Kawasaki trannies don't allow shifting unless the bike is moving. Does that apply to the '88 motor or is it just messed up?

Thanks in advance guys

-Chris

[Gorilla25]

sounds like fun. Good luck

[choneofakind]

welcome to ninjette!

Originally Posted by christeeezy

I'm assuming that the carburetors are gravity fed. Am I right?

No. They're vacuum fed. The carbs create vacuum, and the petcock allows gas out as long as there's vacuum. that's why there's 2 hoses to the petcock. One vacuum, one fuel

Originally Posted by christeeezy

Secondly, is there a wiring diagram anywhere that's strictly for ignition? I would like to do away with all other electrical systems, and the full wiring schematic gives me headaches lol.

No. You're going to have to go through there and just white out everything that doesn't go through the ignition. I'll try and do that this weekend when I'm not busy. Should only take like a half hour or so.

Originally Posted by christeeezy

Also, I took the motor top end apart the inspect for damage. This means I had to remove the camshafts and cam chain. Is there a good guide for doing timing on our motor? And it turned out that one of the pistons were badly scored on the side. I've sourced an '05 motor with rod knock, will its top end (head, pistons, connecting rods) work on an '88 crankshaft and journal bearings? Conversely, will the '88 crank and journal bearings swap directly into the '05?

I know this has something to do with the dots painted on the cam gears. @Racer x might be able to help here.

Originally Posted by christeeezy

Also, I tried looking through the service manual, but couldn't figure it out. What is that one random electrical post above the transmission case for? It had two red wires soldered onto it and the wires were incased in black tubing to give the impression of one wire.

My guess is thats the sensor to tell the CDI where the engine is, because the sparks fire at a certain amount of time BTDC at certain RPM's. Also, the CDI tells the tach how fast the engine is turning.

Originally Posted by christeeezy

One more question. I've tried shifting the transmission through the gears just to see if it would. It seems that it wont go past 1st, or neutral. I googled the problem and read that some Kawasaki trannies don't allow shifting unless the bike is moving. Does that apply to the '88 motor or is it just messed up?

The bike won't shift out of first or neutral unless it's moving.

[Racer x]

Sounds like a fun project. The trans will not go to second without turning the output sprocket. Just try pushing the wheel forward while shifting it should go.

Yes the top from an 05 will fit an 88 bottom. But how is the bottom ? You will need a manual to put it together there is a lot of details. Like valve adjustment and the like.

The carbs are gravity fed on the ninja. The vacuum line is to open the fuel valve. So you will have to mount the fuel tank above the carbs or run a low pressure fuel pump. Or go FI haha

Post up some photos

[choneofakind]

Oh oops I was thinking the petcock. The petcock is vacuum operated. The tanks's gravity fed. my b.

[csmith12]

Welcome and awesome project! Got any pics of progress so far?

[zzrguy]

i just finished a whole engine rebuild on a ninja 250 so if u have questions pm me
as for this

One more question. I've tried shifting the transmission through the gears just to see if it would. It seems that it wont go past 1st, or neutral. I googled the problem and read that some Kawasaki trannies don't allow shifting unless the bike is moving. Does that apply to the '88 motor or is it just messed up?

if you have the bottom apart you can take apart the tranny and there will be three ball bearings in one of the gears, if your remove these you can shift past neutral while stopped. these balls go flying out into a spacer made for them and then allow you to shift into second

[christeeezy]

Awesome, thanks for the warm welcomes and speedy replies guys.

So since the carbs are gravity fed, it looks like I made a smart choice in buying a fuel pump with my kart parts order. It is pulse operated, I went that route over an electric pump because the <1psi pumps are $$$. The issue now is that I'll have to find or make a port for the pulse signal.

I ended up actually finding an ignition-only diagram:


I also found a color coded one in pdf format.

Good to hear about the '88 and '05 compatibility. I'll probably just end up putting the '88 crankshaft into the rest of the '05 motor. Now to figure out timing...

As for pictures, I've only got three lengths of steel welded up for a frame base so far. It's not much to look at right now but my parts order should be coming in in the next couple days. I'll definitely post some up then. I might even use this thread as a build log if it's okay with the mods .

[Racer x]

That is the diagram you need. It is not easy to remove all the unnecessary wiring from the harness, You don't need the kick stand switch and diodes but removing them will get you in trouble.Just cut away the lights and at this stage just use the wiring like it is . Bundle up the stuff you don't need until you get the thing running .You will have to make a wiring harness in the end any how.

The only difference I have found in first gen motors is the last year or so the head was different and the pistons shape. But if you are using the whole top end you should be OK.

We still like pics . Start a Blog and just post stuff. It is all good

[CynicalC]

Subscribed. I had a similar project years back with a 660 out of a wrecked raptor. I agree to just leave the harness complete. Also, take a few minutes and label / color code everything before stripping it off the bike.

[christeeezy]

Originally Posted by CynicalC

Subscribed. I had a similar project years back with a 660 out of a wrecked raptor. I agree to just leave the harness complete. Also, take a few minutes and label / color code everything before stripping it off the bike.

See, that's where the problem is....



She's already all stripped down into pieces lol. Hence my wiring woes. The diagram I posted earlier should help out a bunch though.

Anyway, wiring is a ways off for me. Still need to finish welding up a chassis, and also buy the '05 motor and do the crank swap/timing. Can't finish the chassis until I get my huge order from UPS. Can you imagine how anxious I'm getting?

[CynicalC]

It'll be fun for sure. My friends and I had the luxury of starting with a briggs and stratton mini baja competition chassis. So it was mostly a matter of swapping that stupid 150cc out, custom fabbing the shifter components and wiring.

Did that bike happen to come with a tail light assembly you'd be willing to part with? I stupidly got rid of mine when I sold my tail section.

[christeeezy]

Nice, do you have a picture or two of your Baja? I really wanted to use a 600cc or bigger motor for this project. But the 250 was too good of a price to pass up.

As for the tail light assembly, I believe it did have one. But a big amount of parts on this bike were broken. I'll check the condition tomorrow. If it's fine, I'll just give it to you for the cost of shipping. Or you can swing by to grab it since you're here in the Bay.

[CynicalC]

I know I have a few but I'm gonna have to dig for them. This was the age before Camera phones. So I have pics and video from a camcorder on one of the hard drives in the stack. What part of the bay are you in? Not too many up north by me.

[choneofakind]

Originally Posted by christeeezy

I really wanted to use a 600cc or bigger motor for this project. But the 250 was too good of a price to pass up.

kinda like this? Looks and sounds like a mini F1 car

Link to original page on YouTube.

and here's an offroad version

Link to original page on YouTube.

[christeeezy]

Yup kinda like the first one without the body panels or airfoil or rollbar.

It's okay though, this 250 motor has enough horsepower to be plenty dangerous on a properly geared kart, even 10hp Briggs motors will hit 60mph fairly quickly. Plus I have a secret weapon of a mod that will be incorporated when the build is complete: .

You can see here how 4-stroke 250cc's still hold their own.

Link to original page on YouTube.

CynicalC, the tail light assembly is broken into multiple pieces, sorry. But to answer your question, I'm from the East Bay.

[choneofakind]

Well then if you go with pod filters on the carbs, and a free-flowing exhaust, and jet correctly, you can expect around 30 hp. 300% improvement

How much more will that setup weigh with with the N250 engine though?

[christeeezy]

The chassis and parts will weigh around 120-150 max altogether. So that, plus the weight of the motor. About 200? Still, a good amount lighter than the stock bike I'm assuming.

[flynjay]

I see plenty of parts on that carcass that are salvagable. You can make at least $200 from what I see.

I would be interested in buying the left rearset if it is not mangled.

[choneofakind]

flynay is right. plenty of part-out pieces there.


A stock pregen is about 305 dry. http://en.wikipedia.org/wiki/Kawasaki_Ninja_250R