Kawasaki KLR 650 Forum - Reply to Topic
1987 to 2007 Wrenching & Mods For maintaining, repair or modifications of Generation 1 KLR's. 2007 and earlier.

Thread: CDI compatibility Reply to Thread
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  Topic Review (Newest First)
04-02-2018 10:10 PM
nimac Just an update, end up just slapping on the alternator rotor and the side cover complete with stator and wire plugs, off the Gen1 motor onto the Gen2 motor, hit the starter and it fired up straight away. As the Gen1 hardware is all there on the bike, didn't have to change a thing, very easy transplant Done over 2000kms, no problems!
An observation though, I would say the magnets are the same on the Gen2 rotor, they just replaced the 2 exciter coils with charging coils, that might explain the miserable 3 amp higher output of the Gen2 bike.
03-23-2018 01:33 PM
Originally Posted by nimac View Post
Yes, it's getting a bit complicated, even if that idea worked, I'd have to alter and re-balance the gen2 rotor trigger strip. I think I'll just put the gen1 rotor and stator on the gen2 motor, job done!
Don't forget, you'll need a Generation 1 ignition coil, also.

Pickup coil, same part number? Don't know.
03-23-2018 12:27 PM
nimac Yes, it's getting a bit complicated, even if that idea worked, I'd have to alter and re-balance the gen2 rotor trigger strip. I think I'll just put the gen1 rotor and stator on the gen2 motor, job done!
03-23-2018 11:20 AM
Damocles The existing schemes, Generation 1 and 2, ignition-wise, are all scaled and scoped individually for their intended purposes: Each delivers a spark at the right place at the right time.

Rube Goldberging a scheme to operate a Generation 1 CDI off a Generation 2 stator seems, to me, not unlike:

1. Build wooden frame house.
2. Tie up pig inside house.
3. Set fire to house

As a recipe for roast pig.

Not that the scheme you propose won't work, but . . . a look at Tom Schmitz's experience, implanting Generation 1 ignition onto a Generation 2 bike, should be instructive (if not a cautionary tale!).
03-23-2018 08:56 AM
nimac Hmmmm, well then what about something like this:

*ebay.com.au/itm/50W-150W-Inverter-Boost-Module-Board-DC12V-to-AC110V-220V-Transformer-Converter/292390278949?hash=item4413d19725:g:QXQAAOSwYc5aR2U j
*put in the www

to supply say 60 to 100v AC ?
I'm not sure about the high frequency square wave part of it though, I don't suppose anyone has put a scope on the exciter coil output?
03-23-2018 07:40 AM
Originally Posted by nimac View Post
OK, so what sort of ac voltage range are we talking for the klr alt exciter coil output?
I ain't sure, but the voltage varies with rotor speed, and since it's AC it can be transformed to a level (if necessary) to charge a capacitor with 400 or so volts when rectified.

Here's what Wikipedia says about your DC-powered CDI:
The DC-CDI module is powered by the battery, and therefore an additional DC/AC inverter circuit is included in the CDI module to raise the 12 V DC to 400-600 V DC, making the CDI module slightly larger.
My guess, the exciter coils operate at a level from 40-100 volts, stepped up by a transformer in the CDI module and rectified to charge the internal capacitor. PURE speculation on my part, never measured exciter coil output.
03-22-2018 11:17 PM
nimac OK, so what sort of ac voltage range are we talking for the klr alt exciter coil output?
03-22-2018 01:30 PM
Damocles nimac asks,
What are your thoughts on this idea to power a gen1 cdi off the battery to work with a gen2 motor?
A hard row to hoe, with existing hardware!

A higher voltage indeed is required for capacitor charging. Now, there EXIST, both AC-powered and DC-powered CDIs. The DC-powered CDI has internally an INVERTER, converting DC to AC, where its voltage can be "stepped up," then rectified to charge the capacitor.

The Generation 1 KLR650 CDI is of the AC-powered persuasion, persuasively!
03-22-2018 01:23 PM
Damocles Quote from pdwestman's post:

The Gen 1 ignition is an (AC Voltage) exciter coil powered Capacitor Discharge Ignition.

The Gen 2 ignition is a DC voltage powered Transistor Controlled Breakerless Ignition.

They both use the magnetic Hall effect Trigger coil along the outer perimeter of the flywheel.
Just a comment or two; it ain't the "Hall Effect" on either Generation's ignition system, IMHO. Rather, induced current into coils from a moving magnetic field.

Other stuff, quite correct: The AC voltage from the exciter coils far exceeds 12 VDC from the charging coils; this higher voltage (it may be transformed even higher) is rectified to charge a capacitor; the capacitor is discharged by a THYRISTOR, a silicon-controlled rectifier (SCR), triggered by a pulse from the pickup coil; that's the story of, that's the glory of, CDI!

Generation 2 battery voltage saturates ignition coil primary windings; a pulse from the pickup coil BREAKS this circuit via a THYRISTOR (SCR); the collapsing magnetic field induces current in the secondary ignition coil windings, producing the spark, as pdwestman says.

BTW: Generation 1 and Generation 2 ignition coils are DIFFERENT. Engine may run on either, but mixing them up won't produce optimum operation, in my estimation.
03-22-2018 12:35 PM
pdwestman The AC voltage charge to the capacitor is greater than 12v, but low in amperes. A CDI ignition coil operates on the rising spike of voltage going into the coil From the Capacitor.

The TCBI ignition coil operates on the collapsing magnetic field after voltage saturation by DC current, like an old breaker point system coil.

Click on "Tom Schmitz" member name and search his 'Threads Created'. He did convert his Gen 2 TCBI back to the older Gen 1 CDI. So maybe just read his thread for end to beginning.
Or the info might be over here, at his souperdoo site?

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