Ninja upgrades = ZZR250 Super Ninja :)

[Mohawk]

I've had my ZZR250 for 7 years now, I bought it as a winter bike & its been used slightly in the winter whilst I reworked my VFR800 each winter.

This year there was not much that needed doing to the VFR so I decided to treat the 250, to some TLC & upgrades.

Current mods already done include KR1-S Front forks/wheel/brakes & an Ohlins shock from the later Ninja 250R.

This winter I have replaced the KR1-S fork internals with a combination of VFR & VTR1000 fork cartridges/valves/springs & fresh oil. Plus I'll be replacing the forever seizing Tokico calipers with CBR929 Nissin ones, but that will have to wait, so I've unseized the Tokico's for now.

The latest has been to replace the swingarm with a KR1-S alloy one & a Honda VTR250 17" rear wheel to match the front 5 spoke one, with custom wheel spacers, plus a 48 toth rear sprocket by super sprox.
That need a 110 link X-ring chain to allow for the larger sprocket & 15mm longer swingarm. This does not lengthen the wheel base as the KR1-S forks shortened the front by a similar amount, as well as giving a steeper rake angle & shorter trail. Combined with the Ohlins shock I expect the handling to be awesome now, its was much better than standard as was.

I've also converted the coils to CoP units from a CBR600RR, works great, reduces weight & frees up space for ram air duct ! Plus removal of the coil mount brackets makes valve cover removal simpler, just use an 8mm drill on the spot weld to seperate from the engine hanger.

I have added an oil cooler to the head oil feed pipe, thank you Kawasaki for the external oil feed line

I also have a complete clutch from the newer model which will fit & cure the horrible clutch knock that the older engines are famous for at idle due to the plastic buffers they are fitted with that compress & leave the basket loose.

I've also just had a spare cylinder re-seleeved & bored to 66mm to make a 282cc big bore engine. I just picked this up, so will be a while before I have time to rebuild the engine, but hoping for around 40HP, with some other mods I have planned. Which includes a big airbox with ram air feed.

More & some pics as I get round to it.

[spooph]

[Klondike1020]

@Mohawk - I wish I had half of your ambition.

I havn't even replaced the bent forks on my bike yet.

[Racer x]

Can't wait to see photos.
I wanted to build a ZZR 250.

[Mohawk]

OK link to Dropbox with some pics on the bench. Sorry forgot to take them whilst working

https://www.dropbox.com/sh/kcg0auipy...fWBY3anya?dl=0

[Somchai]

Chris I guess you have a service manual, so may i ask you about the timing of the ignition from the ZZR 250?
I'd find nearly all information about her, but only the ignition timing isn't shown anywhere.
Thank you

[Mohawk]

It's the same as the original GPZ250 that became the GPX250/Ninja 250 & later the ZZR250, 10degrees adv at idle, 38degrees adv from 4000rpm. Which is as good advance number that most bikes tend to run to cover all fuel quality options. You could go to the low 40's with good quality fuel, but not much further.

Ignition timing on its own is not much use, you need to combine it with cam degreeing for the dynamic compression ratio. Ideally a fully tuneable ignition advance would be best, so different values all through the Rev range. What works at 14krpm is not right for 8krpm !

[Somchai]

Thank you Chris for your answer.
But then I should ask if your bike is not the H-Model, because for that the information one can find in the web is:
10 degrees @ 1,300 rpm
42 degrees @ 4,500 rpm
while the GPX or to say the pre-gen comes with the timing like you said.
By the way the timing of my Ninja (2011, FI-Model, Non-EU) is
20 degrees @ 1,300 rpm
46 degrees @ 4,000 rpm
without any problems and yes I use 95 RON-Fuel (and when the info is correct the addition of ethanol is max 3%).

[Mohawk]

Mine is a H12 IIRC, the only manual I could access this morning was a GPZ250 one from which this engine is derived. The mechanicals are the same, only carbs, exhaust & electronic timings in the ECU differ. I'll bow to your research, I have the ZZR250 supplement to the ninja 250 manual, but it's on a dead PC at the mo due to loss of PSU.

[Racer x]

Any idea on your compression? 46 deg is a very long lead time for the spark. I have very high compression. And have gone above 45 deg on an ignition map. But I used 115 octane fuel.

[greg737]

Ideally a fully tuneable ignition advance would be best, so different values all through the Rev range. What works at 14krpm is not right for 8krpm !

I agree...

but it goes even further than that: The ignition advance that works best at any given RPM with a lean air/fuel ratio is not the same number that works best for a rich air/fuel ratio. Rich mixtures burn faster than lean mixtures which means that for the exact same RPM a change in A/F ratio without ignition advance compensation will move moment of maximum dynamic pressure in the cylinder one way or the other (with the danger being a suddenly rich A/F ratio moving things back toward/into knock territory).

[Mohawk]

Just managed to check the zzr supplement to the pregen ninja manual. Timing is 10degrees at 1200rpm then 42degress at 4500rpm+.

I fully agree that the ignition advance should match the AFR, but load has a major impact on that. I'm happy to leve the ignition stock & the CoPs probably as a degree or two to those figures due to the shorter spark path. Then adjust the AFR to suit the spark timing.

On my 800 I have a Rapid Bike Racing model to control fuel & ignition values.

[Somchai]

Yes all what's said is right and please let me add some more about ignition.
When I've been thinking about advancing the ignition of my Ninja I found a static advancer kit by 5 degrees.
At that point my information from the Kwaki manual was 13 degrees @ 1,300 rpm and 38 degrees @ 6,000 rpm.
So I'd order the advancer kit and installed it and the first impression was: WOW - but it was not only the point that the engine feels much stronger now, also the water-temperature went down by 8 degrees Celsius.
I'd make many test rides to check if the engine is knocking, but there is nothing to hear, which doesn't mean there could be silent knocks.
Some time ago I made a contact to a guy who is hacking ecu's, so I bought one, send it to him and he'd give me the information from within.
With this I found out that the Kwaki manual is nothing worth, since the given infos are not the same like what's in the ecu (see my info from last post).
With this knowledge I'd set up my fuel with the Leovince FAST-Fuel System (the same like a PC-V) and have my engine now running without any vibrations (really!).
I think I should add here, that I'm very well able to feel if an engine is running rich or lean with all my technical knowledge and background and the only thing that left me standing with an open mouth was, when I saw an old Italian mechanic synchronising the 12 carbs of a Ferrari by nothing else but his ears.
So to add to what greg737 said, the best or highest power you'll get with the most possible lean setup. Also take my word, a setup based on AFR only is never the best or a good one (to say it diplomatic).
Also important to remember is, that one never should rely on one value or number only - it's the whole package what makes it (the type of the piston, combustion chamber and all the rest).
When one reads in the forums, one can see that many guys all the time only rely on one point of modification and never or in very few cases take a look at the whole package and since those talks always build up more and more there is many wrong knowledge around by now.
So at least here's a picture from the ignition of the original Kwaki Race-Kit for the ZXR400.

[Somchai]

Chris the ignition info what I'm looking for is the ZZR250 H-Model with 40 hp (EU and NZ).
The values for the 36 hp and 38 hp models can be found in the web, but for the 40 hp model the only finding is, that the ignition is advanced.
The 40 hp model was available only in Europe and New-Zealand, the same bike for Canada came with 36 hp only.

[Racer x]

One more thing with the ignition map. I use the BRT and have an adjustable timing. This is great as the 250 ninja has an area between 6500 and 8500 when the power band flattens out. Adding timing in that area really smooths out the power band

[Somchai]

Originally Posted by Racer x

One more thing with the ignition map. I use the BRT and have an adjustable timing. This is great as the 250 ninja has an area between 6500 and 8500 when the power band flattens out. Adding timing in that area really smooths out the power band

Eric maybe the attached picture for you could be from interest.
It's the part of an ignition map from an Indonesian racing team for the N250

[Racer x]

Thanks ,that is interesting. And it shows how well the 250 ninja is designed.

Kawasake was interested in a learner bike. And wanted to improve ride ability for new riders by increasing bottom end torque while meeting stringent emmitions.

I think they did a great job at that. Unfortunately the did so by decreasing volume and increasing velocity of the air fuel ratio.
Small valves and a converter make the top end power much lower that it could be if they intended to build a race bike.
All these numbers are for a low compression engine with street fuel.

These bikes have potential. As we can see.

Speaking of which. Let's see some pictures.

[Mohawk]

I thought \I already posted this link, so trying again

http://www.dropbox.com/sh/kcg0auipyn...fWBY3anya?dl=0

[Racer x]

I am very envious of the aluminum frame.

[Mohawk]

The frame is very similar to the KR1-S's a bike famous for its handling. The ZZR frame uses similar dimensions, but is not as deep in the main spars, so is not as stiff, but there's not a lot in it. My ZZR with the KR1-S front & rear ends should be excellent.

KR1-S Picture
https://upload.wikimedia.org/wikiped...saki_KR1-S.jpg

KR1-S Wiki
https://en.wikipedia.org/wiki/Kawasaki_KR-1/KR-1S


ZZR250 Picture
http://s277.photobucket.com/user/zed..._0548.jpg.html

[Mohawk]

Well having struggled & cleaned what appeared to be clean carbs 5 times & replaced the idle jets & used a rebuild kit on the carbs. I was convinced it would be cured, but once again started whilst cold on the bench, but failed to stay at idle when hot. Regardless what I did it died.

Having checked & adjusted the valves whilst waiting for the jets, there was nothing left to adjust, so what could be wrong ?

So in an act of desperation, I thought back to what else had I changed last spring whilst overhauling the bike ? Well the coils were replaced with COPS, and it seemed to fail as soon as the fan came on ! So as the old ones were sitting on the floor, I thought I'd try with the old ones temporarily rigged up & BINGO, the thing runs until its well hot, survived multiple fan events. So it looks like the CBR600RR COPS I have are crap

Anyone else done COPS ? Which ones did you use ? The CBR ones are the perfect size.

[Triple Jim]

That brings to mind a song...

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

[Mohawk]

Very good ! Made me chuckle.

[greg737]

Posted via Mobile Device

[greg737]

I used 2005 Honda CBR600RR COPs (the Denso "shorty" stick coils) on my 1993 Suzuki GSF400 and I'm just about to do the same conversion on my 2005 EX250. The GSF400 loves the Denso coils, runs great, no problems ever.

It sounds like you were getting a voltage drop on your COP's electric supply line when the fan would come on. On modern cars and motorcycles the ECU corrects for electrical system voltage drops. For example, the electrical system voltage drop that occurs when the starter engages can cause the ECU to increase the coil dwell time by up to 200%. The difference between the time needed to charge a coil to full saturation with 8volts is substantially longer than with 12volts. Without compensation your engine might not get sufficient spark to continue running.
Posted via Mobile Device

[Mohawk]

Thanks Greg. I think they must be faulty, as one of the originals was & the seller replaced it. They are ex college race car use, so maybe shafted, but they were cheap. They worked fine when first installed for a couple of hours on my drive, with multiple fan engagement, then it stopped on a test run & I was convinced it was the carbs, which I still believe were an issue originally, as after the second clean it always started, but would not idle.

I have a local breakers that has a bunch of ZX9R coils at a reasonable price, so I'll compare to the CBR ones for size. Unless anyone else knows if they will fit ?

[Mohawk]

I acquired another set of CoPs & get exactly the same issue, where it starts from cold fine, but as the engine reaches operating temperature the ignition fails. If I pull hot CoPs & replace with the other set which are cold, it fires right up again until these get hot, then it fails.

Swap back to Kawasaki originals & it just works, so I think I'll stick with the originals.
Amyone else had issues ?

[Mohawk]

Well I solved the mystery, after a bit of internet research, it appears the the CoPs draw to much juice from the CDI. The old coils draw 0.5amp, the CoPs draw 0.93amps which is almost twice what the standard coils draw.

Stock coils have 5+ohms initial primary resistance & the CoPs have 3.5ohm initial.
Stock secondary is 19K/ohm+, CoPs are around 10-11K/ohm.

So I bought a couple of 2ohm resistors, added them to the primary feed circuit which lowers the draw to 0.6amp & it runs fine on the CoPs. Although this is not an answer, as the ballast resistor is ceramic coated but according to my IR temp gauge they run at 112 degrees celcius ! So not a simple pop it in the wiring & forget it job as it would melt its way out & thats in the open rather than under the tank in a hot place.

Anyone know of some higher resistance CoPs ?

[Triple Jim]

Not to be picky, but if our ignition systems were capacitor discharge type (CDI), the low resistance wouldn't be a problem.

What is the power rating of the resistors you're using? There's nothing inherently wrong with using the series resistors. The inductance of low resistance coils is low, and current can get flowing much faster than coils with higher resistance, and hence higher inductance.

I used ballast resistors on one of my motorcycles for a while, and used ones that were rated for 25 watts. I bolted them to an aluminum heat sink and everything stayed mildly warm. This was a points system, so the current was higher, hence the high power rating:

[greg737]

Not to be picky, but if our ignition systems were capacitor discharge type (CDI), the low resistance wouldn't be a problem.

But... the EX250's ignition system isn't CDI, it's a TCI system.

(yeah, everyone uses the "CDI" acronym when referring to the EX250's ignition control system, but that's only out of ignorance)

But here's the big/gigantic/enormous/too-big-to-possibly-miss hint that our EX250s have standard, good-old-fashioned TCI type ignitions: look at the wiring diagram and check to see if the coils are connected up to 12volt power. If you find that the coils are hooked into 12volts on the bike's wiring harness you've got a TCI ignition system.

And... and, and, and... the Honda CBR600RR stick coils that the OP is working with are also from a TCI style ignition system. In the motorcycle industry the only time you'll see a CDI style ignition system installed is when the bike's electrical system is very basic or rudimentary, like the motocross bikes used to be (although now even the motocross bikes are running Fuel Injection systems, which by their nature require a good bit of electrical power, so the manufacturers are installing better generators and R/Rs and with that TCI systems rather than CDI).

[greg737]

Well I solved the mystery, after a bit of internet research, it appears the the CoPs draw to much juice from the CDI.

Stock coils have 5+ohms initial primary resistance & the CoPs have 3.5ohm initial.
Stock secondary is 19K/ohm+, CoPs are around 10-11K/ohm.

Wait, what? Where did you get those numbers for the stock Kawasaki coils? My Kawasaki Service Manual Supplement (for the later years of production for the "pregen" EX250) says that the coils are: 2.2 - 3.5 ohms in the primary windings and 10 - 16 kOhms in the secondary windings (with plug cap removed).

If Kawasaki is accurate with their quoted specifications (mild sarcasm here), and if the specifications you listed for the Honda (Denso) COPs are correct then you've got a very nice match.

it appears the the CoPs draw to much juice from the CDI.

The COPs don't draw any juice from the CDI. At least, they're not supposed to be wired anything like that. Those Denso Corp. stick coils are supposed to be wired into the bike's basic wiring harness to provide them with (key switched) 12volt power. The "CDI" only provides a ground path for the coils (when the "CDI" breaks the ground path to a coil, after a proper length dwell time period the saturated field of the primary winding collapses which induces a high-order collapse in the coil's secondary winding which is transmitted via the high tension lead to the spark plug which fires the air/fuel mixture in the cylinder).

[Triple Jim]

Originally Posted by greg737

But... the EX250's ignition system isn't CDI, it's a TCI system

Yes, that's what I was saying.

[greg737]

Originally Posted by Triple Jim

Yes, that's what I was saying.

Sorry then, your mode of speech/typing confused me when you jumped on the resistor thing with such gusto.

[Mohawk]

OK, maybe I muddied the waters, with the use of CDI. Yes its a switched system & yes the coild are directly connected to 12V supply via the main fuse, ignition & kill switch, the other lead goes to the igniton switching unit.

I hear what you are saying, I have done this mod on other bikes & they all worked fine, this problem is a first for me. Others claim to have done this succesfully.

The figures come from my Fluke digital multimeter a top bit of kit. All I know is this fails which may be down to the trigger system overloading but works fine at 0.6amp draw.

Either way one thing I did discover is that the spark is much stronger with the old coils & the engine runs smoother ! Nice fat Bright Blue spark with stock coils & a fairly ordinary orange one with 3 different types of CoPs I have to hand.

[Triple Jim]

Chris, you've just squashed any thoughts I might have had about going to coils on my plugs. Do all three sets of your COPs have similar primary resistances?

[Mohawk]

Jim, I'm not certain is the ZZR250 & the Ninja 250 have identical electronics, but you can check by testing your coils.

[Triple Jim]

I see your point. My '05 250's coil primaries are about 2.4 ohms, as measured with my Fluke, and subtracting the meter lead resistance. The manual specifies 2.1Ω to 3.2Ω.

[greg737]

Originally Posted by Triple Jim

I see your point. My '05 250's coil primaries are about 2.4 ohms, as measured with my Fluke, and subtracting the meter lead resistance. The manual specifies 2.1Ω to 3.2Ω.

I see where the basic manual specifies the coils at 2.1-3.2 Ohms primary and 10-16 kOhms secondary, but that's in the basic service manual which was for the '86-'87 EX250.

The Service Manual Supplement (covering changes specific to the remainder of the pregen model years, '88 to '07) specifies 2.2-3.5 Ohms for the primary winding.

[Triple Jim]

Yes, I didn't check the supplement, but that difference is not particularly significant. Two different meters could measure the same coil and show that much difference, which is less than 10%.

But I will learn from your post and check the applicable manual next time.

[Mohawk]

I think the critical measurement is how much current the coil draws, the originals on mine only draw 0.5amp ! anything much above that appears to overheat the switching unit.