.
The MC28 does, one for the road one for the track. Nigh impossible to derestrict.Originally Posted by Ixion
The MC21 has different engine maps for each gear with 4th 5th and 6th being retarded to lower top speed. You splice the 3rd gear map to the other three and bingo, full power.
Also uses a throttle position sensor and a control system for the powervalves.
What a headache.
Forum whore
If it has a seperate charge coil and triggers it will be CDI,most older 2 strokes were CDI,and '80's Honda's were too,with charge coils in the stator and the trigger in the right case.CDI is used on bikes,specialy 2 strokes,because the intense but very short duration spark will blow off fouling deposits.The short duration of the spark is bad for emissions,so CDI started disapearing sometime ago.
Kawasaki were one of the first to use CDI,and they used the surface gap plug - so when I had my KT250 I tried a surface gap plug (outboards used CDI and surface gap plugs too,we did outboards too,so pocketed a plug).OK,so it started and ran,maybe even ride it - but a normal plug was way better.
Highway Biker
I copied this from another site but I know this works as i have often bodged on another cdi unit off a different bike and it's always worked.
Unfortunately the diagrams didn't copy but there is a website address at the bottom so if you're interested you can just go there.
Anybody got a xt200/ag200/trike200 motor they want to sell?
A Simple Motorcycle Electronic Ignition Replacement.
There are many motorcycles which use electronic ignition systems and all have one thing in common, the black box costs a fortune.
For those with small bikes, the costs of replacement can be minimal, as they all have the same basic design. The following simple modification has been run quite happily on Honda NS125, KTM 125 and Yamaha TZR125. All had no electronic ignition systems other than the contents of the generator on the engine. Typical set-up.
Inside the rotor are usually two main coils. One coil is fairly large and supplies about fifteen to thirty volts AC to the rectifier for the battery and lights. The other coil is a smaller, more finely wound coil to supply a hundred or so volts to the CDI unit. Outside, or sometimes inside is a small thumb sized pulser coil, which triggers the CDI at the correct time for the spark.
Remove the rotor and the coil mounting plates. Inspect the wiring to each coil and make a note of the colours to each. Locate the fine wound high voltage coil inside the flywheel generator and inspect the components carefully.
Eventually there will be an earth wire, and a wire or two from the high voltage coil, a wire or two from the heavier coil for the lighting and battery charging, plus a wire or two from the small pulser unit.
In some cases, the small pulser coil and the high voltage coil may not be earthed, so will have two wires each, one from each end of thier coil of copper wire. As these components normally use an earth, then this can be done by extending the wires and terminating them to an earth tag outside the crankcases. If this deos not work, then they are probably connencted inside theorigional CDI unit, but for the C90 unit, they can be earthed.
The larger lighting and battery charging coil may have two outputs, this is usually one for charging the battery and the other for direct lighting. Simply place a headlight to each, to see which is which, once the engine is running. Headlights can work quite happily on AC, so no fancy electronics is needed. For charging the battery, use a single diode. If revving heavily on a regular basis, then a voltage regulator will keep the battery from boiling. If direct lighting keeps blowing, simply fit larger wattage bulbs or add a simple 6 or 12 volt limiter to the headlight circuit. A limiter is a cheap and basic device which simply bleeds off excess voltage, so the bulbs do not blow.
The spark from a C90 ignition will jump the gap in a 50cc to a 1500cc bike, as all spark plugs are essentially the same. There is no need to have a big CDI unit for a big bike. The only time a big CDI unit is needed is for a multi cylinder machine. (If the cost of four C90 set-ups is one tenth the cost of the genuine article, then at least have a try at fitting four sets.)
The electronic ignition of many motorcycles and similar machines with electronic ignition can be run using the cheapest and most easily available electronic ignition in the world. Honda C90 parts are available from all second hand bike dealers and breakers, usually for a few pounds, always try to get the wiring loom as well, or at least the part of the wiring loom between CDI and engine. The parts needed are the CDI unit, the wiring loom connector and a foot or so of attached wire, and the ignition coil.
The simple sand commonly available Honda C90 CDi unit works very well with most small two strokes. Occaisionally, it also works with many fourstrokes which use a mechanical advance and retard unit. To check for a mechanical advance unit, it looks like a set of bob weights restrained by small springs which will fly out when running. This is common on most fourstrokes with points and can also be a conversion for some older machines.
The picture shows that coils are now very small, some not much bigger then your thumb by using much higher primary voltages from the electronics box, they can now be placed in the spark plug cap, and each coil triggered from the electronics individually.
The basic set-up.
Wiring diagrams use a colour code. The normal Japanese set-up uses western nomenclature. BK black. BU blue. R red. Y yellow. W. white.
The Honda C90 CDI unit is very simple and has only five wires.
The earth, the pulser coil input, the high voltage input, the output to the spark plug coil, and the kill switch wire.
To this will be needed a spark plug coil. Look for the CDI mark on the grey plastic coil body. The latest mini coils are also very good, and can be attatched directly to the top of the spark plug, with a little modification. Older points coils are not suitable.
The earth.
Green.
This must connect to the engine casing, and to the frame, so the kill switch will also work.
The pulser coil input.
Blue with yellow tracer.
This simply goes to the pulser coil. The change in magnetic field as the flywheel rotates, causes a small trigger spike of electricity to discharge the big capacitor in the CDI unit into the ignition coil. If the timing is out, then the two wires on the small pulser coil may need to be swapped, so the north-south magnetic pulse is reversed. This allows the trigger to occur at the front or tail end of the pulser strip on the outside of the flywheel. So if your ignition timing is out, swap the pulser wires around.
The high voltage input.
Black with red tracer.
This supplies electricity from the coil inside the flywheel to charge up the big capacitor inside the CDI unit, so it is ready to be discharged by the electronics, upon command from the pulser unit.
The output to the spark plug coil.
Black with yellow tracer.
This discharges the energy in the big capacitor into the high tension coil to the spark plug, changing it from a hundred or so volts up to the 20,000 volts or so to jump the plug gap. The ignition coil must be a CDI type, so buy this at the same time as the C90 CDI unit, so they will work well together.
The kill switch wire.
Black with white tracer.
This simply shorts out the power to earth. In the C90, it simply shorts to earth via the ignition key switch, so the pulse from the flywheel high voltage generator does not charge the capacitor, simply preventing the engine from working.
Also refer to the wiring diagram for the position of the wires if the wiring loom connector is not available.
The diagram includes the checking diagram for the CDI unit. The two probes of a multimeter are placed across the various pin connections, and the appropriate reading is checked.
The measurements are in ohm resistance.
The open ended figure eight on it's side is infinity, so maximum resistance with effectively no connection is required.
SW is the switch , which is the black and white kill-switch wire.
PC is pulser coil.
E. is the earth.
IGN. is the ignition coil
The Diagram.
The big circle is the flywheel stator, with the two main coils.
The thick coil supplies the lights and battery.
The finer coil goes to the black/red wire on the CDI unit.
The small coil on the outside is the pulser and is connected to the blue/yellow CDI wire.
The two measurements beside the ignition coil is the primary and secondary windings.
Primary is connected to the earth and CDI connector tag, and is the low 0.4 ohm resistance.
The secondary has a larger 4,000 ohm resistance and connects to the earth and spark plug thick HT lead, (without the plug cap, which may also contain a resistor).
If the lacquer on the copper coils is damaged, it can be cleaned up and re-lacquered with nail varnish. If the coils are badly broken, they can sometimes be wound back a few turns and rebuilt using more lacquer and wrapping in masking tape. Vinyl tape is not strong enough in the hot engine area. The best wrap is cotton cloth and epoxy resin.
Replace all components ensuring the wires pass through the waterproof seal. If this is missing, then silicone bathroom or gasket sealer is acceptable.
Wire up appropriately as mentioned earlier and check for a spark.
If the engine does not run, check the following.
Disconnect the kill switch wire.
Use a strobe and if the timing is out by twenty or so degrees, then try swapping the pulser coil wires, as the pulse may need to be the other way around North South and vice versa.
If no spark, then swap the high voltage generator wires in the backing plate. This is rare.
Check the wiring is correct.
Check the components are good, using a multimeter.
If all else fails, you have lost just a little cash and some time. The rest is still available for the original and probably expensive genuine CDI unit.
See the home page at www.btinternet.com/~jhpart/index.htm __________________________________________________
Hardcore Biker
Can other cdi's be used the same as the c90 because i don't think we'd have a heap of them lying around here.
wheelie king
Most people fall into this trap CDi CDI CDI most likely your bike has a TCI.
Most modern bikes are modern meaning mid 80s on then you have ECU etc.
the internals of a CDI are very basic we had to make one at Polytech and get it to spark and work and it was heaps of fun.
I haveit written down somewere here and will dig out papper work and tell you about the internals.
Now pretty much to your answer can it be transfered from one CDI to another well so long as the internals are the same and work exactly the same then yes but I mean you see alot of guys running Ignition packs of KX125s etc on bucket bikes liek RG50's
Its pretty simple so long as you have a source a trigger and everything matches it should work
Blindspott are back as Blacklist check them out
www.blacklistmusicnz.co.nz
Hardcore Biker
cheers ivan, I'm getting a kt250(1970's) in the next few days and i think i heard the guy say that the cdi or something in the timing was out. which brought me to think if i can change the whole thing it should get rid of that problem.
i'm not really fimiliar with advancing and retarding but he had to retard/advance it fully to get it to run near right.
Wannabe racer
Very cool site
I've thought about designing an ECU but it hasn't got past the thinking state - hard to get motivated when you play around with micros all day at work. Top effort to the guy for actually making one.
Life is difficult because it is non-linear.
Forum whore
The KT250 was one of the first bikes with CDI,and were pretty reliable for an early system.But time takes it's toll.If he has to play with the ignition timing then something else is wrong - I had a KT250 for 12 years and always ran it full advance....a new piston and seals and it ran perfectly on standard timing.Go to the KT site,Fred in Wellington makes heaps of KT parts and sells them to the world.
Hardcore Biker
so it may need new piston and rings? can you tell me why on an old piston the bike would need to be advanced?
cheers guys
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