SOHC.co.uk Forums > Anorak's Corner
Anatomy of a CX500 Cdi unit
AshimotoK0:
Well the bike is for sale on eBay as a non-runner. One bike project too many and not really my 'bag'. https://www.ebay.co.uk/itm/142870424113?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649
However, I recently fully rebuilt the CDI and rehoused it as shown in the pics on the bike.
Problem is I can't really test it without trying on a bike or building a simulator for the pulser pickups etc but I am pretty sure it will work OK. In the picture is the silicone dielectric gel that Jason (Woodside) kindly donated. The intention was to re-encapsulate the PC once it was found to be running OK.
I have put an appeal into 'Desperately Seeking' for another duff CDI, so that I can carry on the good work. My next step was to come up with a simulator. OK I won't have the bike anymore but I hate to have 'unfinished business'. RGP750 .... I blame you for all of this ;D ;D
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Rozabikes Tim:
Looks a great buy for someone Ash. Super find!
Laverda Dave:
Great looking bike Ash. I've sent the details off to a mate who's looking for an older Honda to ride and clean :)
AshimotoK0:
Well I will be CX less next Monday and the bloke buying it is sending it to a restorer in Anglesey and keeping it standard. Happy it's going to a good home ... he had one 35 years back and wants to get back on a CX.
I am still looking for another duff CDi though if anyone has one. to continue my 'experiments'
I did come up with a crude 'ish test method which tests out the main part of the CDI but not the auto advance function.
I fed the HT AC input from a modified cheapo 12-> 240 volt inverter I got off eBay. I basically bypassed the DC and 50Hz frequency synthesis bit of the inverter and wired straight out of the HT transformer into the CDI. How they can make these little inverters in China and sell for less than £10 beats me.
https://www.ebay.co.uk/itm/150W-Car-Power-Inverter-Adapter-12V-DC-into-11V-220VAC-with-USB-Charger-Port-GY/253755535569?_trkparms=aid%3D555017%26algo%3DPL.CASSINI%26ao%3D1%26asc%3D53379%26meid%3D260deeeafa78406e87de83fe8017ab96%26pid%3D100705%26rk%3D1%26rkt%3D1%26%26itm%3D253755535569&_trksid=p2045573.c100705.m4780
So, for anyone familiar with the CX CDI ( or who is interested ;)) , the high voltage from the inverter feeds into the White and Blue leads on the CDI. ( this AC voltage is normally provided on the bike by an extra coil on the alternator). This AC high voltage is rectified by diodes inside the CDI and charges the main discharge capacitors via the ignition coil primaries. After connecting the coils to the CDI and powering the CDI from the inverter, I fed one phase coil of a stepper motor ( scrap from an old laser printer) between the green wire on the CDI and the Orange (left coil) and Light Blue (right coil). You then spin the stepper motor shaft slowly by hand and you should get a healthy spark across the plug attached to the secondary of the ignition coil. The stepper coil works in reverse to normal, generating pulses from its coils when spinning inside the magnets. These pulses trigger the thyristors in the CDI, via a network of resistors and capacitors. Obviously, these pulses would normally come from the pulser coils rotated by the engine when fitted to a bike.
Seabeowner:
--- Quote from: AshimotoK0 on August 07, 2018, 10:14:11 AM ---Well I will be CX less next Monday and the bloke buying it is sending it to a restorer in Anglesey and keeping it standard. Happy it's going to a good home ... he had one 35 years back and wants to get back on a CX.
--- End quote ---
Wow that must be a wrench letting that go Ash. There must be a couple of bidders kicking themselves. A unique opportunity.
But I hated them at the time, so I must stick to form. Glad it's gone to a good home.
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