So I am planning to rebuild the ninja from the ground up.
What extra mods do you guys recommend?
How hard is it going to be if I take the engine apart including the trans to put back together?
Any good info on the full rebuild of the trans and engine?

So I am planning to rebuild the ninja from the ground up.
What extra mods do you guys recommend?
How hard is it going to be if I take the engine apart including the trans to put back together?
Any good info on the full rebuild of the trans and engine?

All I can really suggest to you is to have the FSM handy. Do you plan on replacing everything? bearings and what not? It's really not that daunting once you've cracked the motor open and exposed the internals. Have the cylinders checked to see if they're within tolerances otherwise bore up and get some new pistons. You can get away with reusing the connect rod bolts for getting your clearances checked as they're a one time use thing. Just be sure to use new ones for final assembly.

I used a lot of paper shop towels to wipe down parts and all that fiber accumulated on the oil screen after doing my first initial oil change after the rebuild. Be careful to not overtorque the bolts. I forgot most of the bolts are in inch/lbs and not ft/lbs.

All I can really suggest to you is to have the FSM handy. Do you plan on replacing everything? bearings and what not?

I plan to replace most if not all the stuff in it. also doing +1 pistons.

Make sure you order all you need at one time since most places charge a relative flat rate $10+ even if it's a small little gasket that could have fitted in a standard envelope.

Make sure you order all you need at one time since most places charge a relative flat rate $10+ even if it's a small little gasket that could have fitted in a standard envelope.

You want to send me a pm with the place you got your parts from? Also do you have a rebuild thread for yours. Did you take apart your trans?

If you do not have any mechanical experience then it can be very hard. Having a workshop manual helps, but they are written for mechanics, so they usually don't go into enough detail for a novice. Cyclepedia have an online manual you can subscribe to, which has full colour photo's, and may explain things better. There are also many youtube videos of people demonstrating how they rebuilt specific engines. Keep in mind though that some are done by novices and may not be doing the right thing.

Read as much as you can about each aspect of the job before doing it.
Buy good tools.
Buy the correct tool for the job. Otherwise you may cause damage to the engine, costing you more money in the long run.
Do not have any time constraints, as this may lead to rushing and making mistakes.

If it is a cheap bike, and you have plenty of time, then go for it. Treat the exercise as a learning experience. Engines are fun to play with.

As far as mods go, the sky is the limit. But conservatively, a rebore with the max size genuine oversize pistons & rings for reliability. Some light cleaning up of the ports to remove any steps/ lips/ casting imperfections, making sure valves are seated well & not leaking. K&N airfilter in standard airbox, ex pipe & jet kit. Larger front sprocket.

You want to send me a pm with the place you got your parts from? Also do you have a rebuild thread for yours. Did you take apart your trans?

I've ordered parts mostly from Cheap Cycle Parts

There's also Ron Ayers, Bike Bandit, and Partszilla. I didn't fully take apart my transmission (gear wise) since I didn't have any issues with it. I just inspected the bearings to make sure there wasn't any play or damage. I don't have a rebuild thread of any sort, but plenty of us can offer you help if you come to snag.

If you do not have any mechanical experience then it can be very hard. Having a workshop manual helps, but they are written for mechanics, so they usually don't go into enough detail for a novice. Cyclepedia have an online manual you can subscribe to, which has full colour photo's, and may explain things better. There are also many youtube videos of people demonstrating how they rebuilt specific engines. Keep in mind though that some are done by novices and may not be doing the right thing.

Read as much as you can about each aspect of the job before doing it.
Buy good tools.
Buy the correct tool for the job. Otherwise you may cause damage to the engine, costing you more money in the long run.
Do not have any time constraints, as this may lead to rushing and making mistakes.

If it is a cheap bike, and you have plenty of time, then go for it. Treat the exercise as a learning experience. Engines are fun to play with.

As far as mods go, the sky is the limit. But conservatively, a rebore with the max size genuine oversize pistons & rings for reliability. Some light cleaning up of the ports to remove any steps/ lips/ casting imperfections, making sure valves are seated well & not leaking. K&N airfilter in standard airbox, ex pipe & jet kit. Larger front sprocket.

I have the tools other then a way to take measurements accurately any recommendations? What do you guys recommend for a new shock?

I will be getting another 250 or a 500 so I will not want to rush this.

I have the tools other then a way to take measurements accurately any recommendations?

Ideally a Micrometer to measure crank journal ovality & taper. But visually inspecting the crank bearing surfaces, and then using Plastigauge to measure oil clearances will suffice. Feeler gauges between piston & bore can be a cheap substitute for a bore gauge.

A useful tool for measuring the round of your piston big end caps and the engine cylinders (in conjunction with a digital caliper) is the telescoping gauges. They're spring loaded and they shoot out while theyre inside your cylinder and you tighten the knob to lock the measurement in place and then measure.
http://www.harborfreight.com/6-piece-telescoping-gauge-set-5649.html


The valve spring compressor is pretty much a must in my opinion if you plan on taking your valves out. I wasn't able to find any generic model that would actually work with the 250's head. I bought mine off ebay and it worked great.

http://www.ebay.com/itm/Heavy-Duty-5-Size-Valve-Spring-Compressor-Tool-Car-Motorcycle-CP128676E-/121000967263?pt=Motors_Automotive_Tools&hash=item1c2c383c5f

You'll need a full set of metric sockets, I'd recommend both deep and standard length. Oil pan, shop rags, beer, music, electric drill with a screw extractor set and hammer, engine stand or small dolly, I'll try to think of more than that.

I'm in the process of putting a steering damper on (even though I think my new front tire alleviated my issue). You could try that out. A jet kit and new rear + front shock is pretty much a must in my book. It'll give you a whole new bike. The bore out is gonna be awesome as well even though I've never done it.

Stainless Steel brake lines up front at least would be a pretty good upgrade. You could play around with a bigger master cylinder if you wanna get crazy.

Maybe a +1/-4 sprocket setup.

Sintered brake pads up front.

I'd say a digital/analog gauge combo but I don't think you have a streetfighter. The fairings and windscreen help this bike a lot fyi....

Bigger tires.

Gear shift indicator.

I think I might throw a fuel pump in the tank one of these days. The bike seems to perform better with a fuel tank and I think it may be the extra bit of weight up top......

For the clutch assembly you're gonna need a clutch holder tool so you might wanna save up/buy that now.

A useful tool for measuring the round of your piston big end caps and the engine cylinders (in conjunction with a digital caliper) is the telescoping gauges. They're spring loaded and they shoot out while theyre inside your cylinder and you tighten the knob to lock the measurement in place and then measure.
http://www.harborfreight.com/6-piece-telescoping-gauge-set-5649.html


The valve spring compressor is pretty much a must in my opinion if you plan on taking your valves out. I wasn't able to find any generic model that would actually work with the 250's head. I bought mine off ebay and it worked great.

http://www.ebay.com/itm/Heavy-Duty-5-Size-Valve-Spring-Compressor-Tool-Car-Motorcycle-CP128676E-/121000967263?pt=Motors_Automotive_Tools&hash=item1c2c383c5f

You'll need a full set of metric sockets, I'd recommend both deep and standard length. Oil pan, shop rags, beer, music, electric drill with a screw extractor set and hammer, engine stand or small dolly, I'll try to think of more than that.

I'm in the process of putting a steering damper on (even though I think my new front tire alleviated my issue). You could try that out. A jet kit and new rear + front shock is pretty much a must in my book. It'll give you a whole new bike. The bore out is gonna be awesome as well even though I've never done it.

Stainless Steel brake lines up front at least would be a pretty good upgrade. You could play around with a bigger master cylinder if you wanna get crazy.

Maybe a +1/-4 sprocket setup.

Sintered brake pads up front.

I'd say a digital/analog gauge combo but I don't think you have a streetfighter. The fairings and windscreen help this bike a lot fyi....

Bigger tires.

Gear shift indicator.

I think I might throw a fuel pump in the tank one of these days. The bike seems to perform better with a fuel tank and I think it may be the extra bit of weight up top......

For the clutch assembly you're gonna need a clutch holder tool so you might wanna save up/buy that now.

I have a +2 -5 on it now.

What tools/cleaners for cleaning parts do you recommend?

Something like this (http://www.craftsman.com/craftsman-165-pc-mechanics-tool-set/p-00938165000P?prdNo=6&blockNo=6&blockType=G6). That's pretty much all you need for most stuff. You'll occasionally run into situations where you need specialty tools or a bigger hammer.

Simple Green is a great all purpose cleaner

Something like this (http://www.craftsman.com/craftsman-165-pc-mechanics-tool-set/p-00938165000P?prdNo=6&blockNo=6&blockType=G6). That's pretty much all you need for most stuff. You'll occasionally run into situations where you need specialty tools or a bigger hammer.

Simple Green is a great all purpose cleaner

I think I have the sockets and wrenches down I was thinking tools for cleaning. like a parts washer or a belt sander. I only have a 6in grinder/wire wheel.

Also what place are you guys getting your rear sets?

Ebay, race forums, craigslist.

Ebay, race forums, craigslist.

Thanks I finely found woodcrafts and will be getting them. In order to get a full race lean angle what do I need to take off/change?

I really can't comment on this but I would imagine the center stand.

I really can't comment on this but I would imagine the center stand.

Yep the center stand will need to go.
Dose any one have any know a good oil temp and water temp censor and place to install them?

Also do they make a way to monitor the oil pressure on the 250?

Yep the center stand will need to go.
Dose any one have any know a good oil temp and water temp censor and place to install them?

Also do they make a way to monitor the oil pressure on the 250?

You can use any type of automotive gauges of your liking or your cheapy Chinese brands. You can tap thermostat housing for the temp probe and mount the gauges on the fairings left and right of the cluster.

You can use any type of automotive gauges of your liking or your cheapy Chinese brands. You can tap thermostat housing for the temp probe and mount the gauges on the fairings left and right of the cluster.

What about the oil pressure? What is the one guys name that drags the 250? racer or something?

What about the oil pressure? What is the one guys name that drags the 250? racer or something?

Not sure about how those hook up but the oil pressure switch can probably be removed and replaced with one if you can find the right fittings for it.

Maybe you mean @racerx ?

Don't forget your clutch holder tool

Not sure about how those hook up but the oil pressure switch can probably be removed and replaced with one if you can find the right fittings for it.

Maybe you mean @racerx ?

Yep I got ahold of him he also recommends a T on the oil light.

Yep I got ahold of him he also recommends a T on the oil light.

What does he mean by a "T"?

A plumbing part T

Well the fun has started. I got a extra 250 for 200.00 its missing the carbs and top of the engine but its ok with me I am going to take it apart first so I can use it as a learning tool for rebuilding the other one.

do you have a tool to pull the fly wheel, and a clutch wrench? Those things might prove to be useful along with a case separator if you plan on going that far.

A compression test could be useful as well

do you have a tool to pull the fly wheel, and a clutch wrench? Those things might prove to be useful along with a case separator if you plan on going that far.

A compression test could be useful as well

Any idea on the size I will need to get?

for what tool?

The clutch wrench should be easy to find a compatible one, just find the size of the plates and find a tool to match.

As far as fly wheel puller, IDK? never done anything like that to the ninja, never had that side of the case even opened yet.

As far as the case splitter, IDK either, I feel like they are fairly universal though or at least one model will cover several engine types, again, never split my ninja case

any motorcycle compression tester should do

So I am rebuilding the extra carbs and I plan to jet them. What jet kit is every one going with now days?

get a full set of jewelers micro drill bits (hand powered) they come in 0.01mmish increments. buy an extra pair of stock mains and pilots (jetsrus.com), then slowly drill them up one size each and test until its right. when you go too far it starts getting ****** so take your second pair and drill to the correct size. make sure you keep it straight or it will get oblong and be too big

get a full set of jewelers micro drill bits (hand powered) they come in 0.01mmish increments. buy an extra pair of stock mains and pilots (jetsrus.com), then slowly drill them up one size each and test until its right. when you go too far it starts getting ****** so take your second pair and drill to the correct size. make sure you keep it straight or it will get oblong and be too big

What is (Slow Jet - 35*)
http://www.jetsrus.com/a_jet_kit_street/kawasaki_250_EX250_Ninja.htm

slow jet is idle jet

get a full set of jewelers micro drill bits (hand powered) they come in 0.01mmish increments. buy an extra pair of stock mains and pilots (jetsrus.com), then slowly drill them up one size each and test until its right. when you go too far it starts getting ****** so take your second pair and drill to the correct size. make sure you keep it straight or it will get oblong and be too big

The idea seems alright. But isn't there a taper and other tomfoolery going on in a jet that by drilling it, will mess it up?

get a full set of jewelers micro drill bits (hand powered) they come in 0.01mmish increments. buy an extra pair of stock mains and pilots (jetsrus.com), then slowly drill them up one size each and test until its right. when you go too far it starts getting ****** so take your second pair and drill to the correct size. make sure you keep it straight or it will get oblong and be too big
Everything I've seen says you can't drill jets. The inside of the jet is a venturi (correction - taper) and not just a straight hole.

Even "replacement" jets that are made for a specific carb won't flow the same as the OEM ones, so you need to be careful when purchasing jets for tuning as one brand of "108" won't flow the same as another brand's "108".

Everything I've seen says you can't drill jets. The inside of the jet is a venturi and not just a straight hole.

Even "replacement" jets that are made for a specific carb won't flow the same as the OEM ones, so you need to be careful when purchasing jets for tuning as one brand of "108" won't flow the same as another brand's "108".

Interesting. Am I able to just order a few larger sizes and try jetting it that way or will they not fit?

it is a taper not a de laval nozzle or a venturi stack. the taper is larger than the amount you'll be taking off so it stays intact unless you're going way too far. you obviously can't drill a needle jet, but taking 0.01mm off the wall of a jet? costs $10 instead of $100

Interesting. Am I able to just order a few larger sizes and try jetting it that way or will they not fit?

no, they use ****** worn out drill bits. so they're typically not exactly accurate to what they should be. you can buy "genuine" or knockoff jets

no, they use ****** worn out drill bits. so they're typically not exactly accurate to what they should be. you can buy "genuine" or knockoff jets

will I need to change the slow jets? they are only a few dollars each so it be a fun learning tool if they do work.

it is a taper not a de laval nozzle or a venturi stack. the taper is larger than the amount you'll be taking off so it stays intact unless you're going way too far. you obviously can't drill a needle jet, but taking 0.01mm off the wall of a jet? costs $10 instead of $100
Ok, taper may be the proper term - whatever it is - it isn't just a straight hole.

You still think it's a good idea to drill it?

I don't think so.

Ok, taper may be the proper term - whatever it is - it isn't just a straight hole.

You still think it's a good idea to drill it?

I don't think so.

I guess only one way to find out if he is just diping the fish or fishing the dip :fish:

i don't like when people say you can't do something with absolutely no reason outside of that someone else told them you can't. so maybe you want to provide some actual resources that talk about why you can't drill a jet?

i don't like when people say you can't do something with absolutely no reason outside of that someone else told them you can't. so maybe you want to provide some actual resources that talk about why you can't drill a jet?

Right. Prove that it works.

Precisely drilling a "taper" that is thousandths of an inch wide and meters fuel is a good idea?

If it sounds like a good idea to you, then do it.

It doesn't sound like a good idea to me, but I can't prove it. Can you?

i just found jets for $2 each. cheap as ****!

http://www.z1enterprises.com/ShopByCategory.aspx?name=Jets&description=Main+jets%2c+pilot+jets%2c+needle+jets+%26+needles&category=0102010206

You can drill a jet. But it will change other properties of fuel flow that you do not anticipate.

Right. Prove that it works.

Precisely drilling a "taper" that is thousandths of an inch wide and meters fuel is a good idea?

If it sounds like a good idea to you, then do it.

It doesn't sound like a good idea to me, but I can't prove it. Can you?

the taper is already there. you're not ****ing it up. the only difference is that ideally the taper would be one or two degrees different for a much larger jet size. but the difference between a 96 and a 98? you are talking about less than 1d angle difference? there are thousands of people who drill jets all the time. if you don't **** it up, they work fine. people say not to do it because most people are worthless and can't do anything without ****ing it up. will a custom made jet be better? sure, slightly. will you be able to notice the difference without a dyno? i doubt it.

i just found jets for $2 each. cheap as ****!

http://www.z1enterprises.com/ShopByCategory.aspx?name=Jets&description=Main+jets%2c+pilot+jets%2c+needle+jets+%26+needles&category=0102010206

Are those legit Keihins or knock offs? I couldn't tell

knockoffs, but for $2, you can order the entire range for only like $20.

the taper is already there. you're not ****ing it up. the only difference is that ideally the taper would be one or two degrees different for a much larger jet size. but the difference between a 96 and a 98? you are talking about less than 1d angle difference? there are thousands of people who drill jets all the time. if you don't **** it up, they work fine. people say not to do it because most people are worthless and can't do anything without ****ing it up. will a custom made jet be better? sure, slightly. will you be able to notice the difference without a dyno? i doubt it.

I was planning to use a drill press in hopes of not fing it up. I guess I will need to get a set of 3 keep one stalk drill out one tell I get it wrong and the 2nd will be my test stock vs drilled.

The next question is do I need any other parts like bigger needles?

the taper is already there. you're not ****ing it up. the only difference is that ideally the taper would be one or two degrees different for a much larger jet size. but the difference between a 96 and a 98? you are talking about less than 1d angle difference? there are thousands of people who drill jets all the time. if you don't **** it up, they work fine. people say not to do it because most people are worthless and can't do anything without ****ing it up. will a custom made jet be better? sure, slightly. will you be able to notice the difference without a dyno? i doubt it.
I think you are. How much increase in dia is too much? At what point do you eliminate the taper? Who knows?

The taper is designed to go from one size to another, and drilling it will change the way it flows.

A drill bit isn't going to give you a perfectly smooth hole as is cuts.

A jet is a very precise part, and running a drill bit through it will damage the precise tolerances and angles.

Really, do it if you feel I'm incorrect - it doesn't matter to me.

I think you are. How much increase in dia is too much? At what point do you eliminate the taper? Who knows?

The taper is designed to go from one size to another, and drilling it will change the way it flows.

A drill bit isn't going to give you a perfectly smooth hole as is cuts.

A jet is a very precise part, and running a drill bit through it will damage the precise tolerances and angles.

Really, do it if you feel I'm incorrect - it doesn't matter to me.

So is that a no on bigger needles?

I think you are. How much increase in dia is too much? At what point do you eliminate the taper? Who knows?

The taper is designed to go from one size to another, and drilling it will change the way it flows.

A drill bit isn't going to give you a perfectly smooth hole as is cuts.

A jet is a very precise part, and running a drill bit through it will damage the precise tolerances and angles.

Really, do it if you feel I'm incorrect - it doesn't matter to me.

you're right. what i'm saying is it doesn't make that big of a difference having the mid jet taper vs not except that they clog more easily. my brother has drilled jets on our minis for years. if you want you can buy real jet reamers that are tapered. a set costs $10 and they are designed to produce a very smooth wall. but the difference between that and a jewelers bit is really not that far off if you don't screw it up.

Needles are all about taper, not size. You can raise the needle height in order to flow more fuel, either by shimming the stock ones, or getting a factory pro needle and jet kit. I would recommend FP.

Needles are all about taper, not size. You can raise the needle height in order to flow more fuel, either by shimming the stock ones, or getting a factory pro needle and jet kit. I would recommend FP.

I was looking on there site last night and no luck on finding a kit for the 250.

http://www.factorypro.com/prod_pages/prodk04.html like that?

So what can I use to make sure the frame and all the faring tabs are back in the correct spot? other then taking off the farings taping the mount putting them back on and see how they fit 100 times?

to day I will hit the point of no return 100% of the engine is coming apart.

Nice! Looks like an undertaking!

Yes it is

And the engine

You got the engine apart yet?

A few questions:

1. How do I get the sleeves out?
2. How do I get the rods in the exhaust side out?
3. Do you see any thing that is really bad?

Also how do I get this off?

Also how do I get this off?

Watch this video-around 1:07 it shows the guy using a particular tool attached to a wrench to remove this part.

https://www.youtube.com/watch?v=zkcax6ZH1IY

The sleeves are interference fit. You have to heat the cylinder block up to press them out.

Watch this video-around 1:07 it shows the guy using a particular tool attached to a wrench to remove this part.

https://www.youtube.com/watch?v=zkcax6ZH1IY

Thanks.. It looks like the gear puller thing I got for taking out the front fork springs lol.

The sleeves are interference fit. You have to heat the cylinder block up to press them out.

Thanks.

The sleeves are interference fit. You have to heat the cylinder block up to press them out.

Also will baking it in the oven work?

Also will baking it in the oven work?
Probably not since it heats everything up uniformly. Are you sure you need the sleeves out ?
(Confess I haven't read the whole thread :) )

Probably not since it heats everything up uniformly. Are you sure you need the sleeves out ?
(Confess I haven't read the whole thread :) )

Nope they look 110% fine to me. But I have never done any of this so I am working at a trial and failure. I am 100% taking the bike apart including the engine. I know every thing is fine with it as it was running 100% fine when I decided to do this. :rotflmao:

Nope they look 110% fine to me. But I have never done any of this so I am working at a trial and failure. I am 100% taking the bike apart including the engine. I know every thing is fine with it as it was running 100% fine when I decided to do this. :rotflmao:

Whew!
That's good. I hate to think that someone would ruin a clunker :D

those pistons are pretty gnarly.


as for the jet drilling, i have a set of micro drill bits and have drilled hundreds of jets over the years. Usually i just use it for tuning, then i go buy the right size of jet, or a range, but more often than not, if it is running good with drilled jets i just leave them alone. If you do plan on running them, file off the # on the side so you don't use them later thinking they are the indicated number... a sure way to screw you up!

jets are just there to flow a specified amount of fuel. or rather, apply resistance to the flow of fuel. nothing magic, they aren't vaporizing it or any such nonsense. Ideally they would be a sharp-edged orifice that has a nice linear flow rate as a function of pressure drop, but in the real world you won't notice any ill-effects from just whacking the hole out slightly bigger.

you can also fatten up your needles (make them more rich) by sanding them down with a tiny piece of fine sandpaper pinched around them while spinning in a drill. It doesn't take much to change them significantly. Pros only.