CDI replacement

[SteveXFR]

The electronic ignition CDI unit in my 1982 GS500E (smaller, import GS550E) has failed. It's the same unit used on the GS550 and GS750 as well as the GS450 & GS250 twins of that age. They seem to be rare and expensive here in the UK. I found something online suggesting that the CDI from the 90's twin cylinder GS500 will work. Can anyone confirm?

[Swiss Toni]

Why replace a knackered, 40yr old unit, with another 30 odd year old item? There must be countless numbers of companies manufacturing new, up to date units. Electrex World, for one!Have a Google.

Edited February 12 by Swiss Toni

[SteveXFR]

3 hours ago, Swiss Toni said:

Why replace a knackered, 40yr old unit, with another 30 odd year old item? There must be countless numbers of companies manufacturing new, up to date units. Electrex World, for one!Have a Google.

 

Electrex World don't have one, I did phone and ask. The only new ones I can find are around £400 while a used one from a 90's GS500 is £65. 

[Wee Man]

Worth trying Ignitech 

https://www.ignitech.cz/en/vyrobky/tci/tci.htm

They might be able to supply one that'll work for you. 

[Suzukian]

Sad thing is that a Military Spec (Mil-Spec) capacitor has a life of 4000 hrs.  That's why the military's throw laptops away after 4 or 5 years, they don't trust them.  I'm not sure what to expect out of consumer grade components.  I managed to pick up 3 CDI units for my '83 GS750ES for around $25 bucks a piece, in case mine blew.  40 years later, it's still going strong. Even the used ones have tripled in price.  Some of these seem interchangeable, but the power curve isn't right, and the bikes won't feel the same.

 

The GS1150 and GS750ES look and have the same plug, but they have different power curves.

[imago]

20 minutes ago, Suzukian said:

Sad thing is that a Military Spec (Mil-Spec) capacitor has a life of 4000 hrs.  That's why the military's throw laptops away after 4 or 5 years, they don't trust them.  I'm not sure what to expect out of consumer grade components.  I managed to pick up 3 CDI units for my '83 GS750ES for around $25 bucks a piece, in case mine blew.  40 years later, it's still going strong. Even the used ones have tripled in price.  Some of these seem interchangeable, but the power curve isn't right, and the bikes won't feel the same.

 

The GS1150 and GS750ES look and have the same plug, but they have different power curves.

Probably worth mentioning at this point that they're not CDIs even though everyone calls them that. Suzuki GS/GSX are TCI so they don't use capacitors, the transistor just shuts off power to the primary coil. Solid state version of points basically.

[imago]

28 minutes ago, TonyGee said:

could be worse, some people call them ECU's 

To be fair that's more accurate than CDI as it's electronic it controls the spark. 

[Dezza]

There's a bloke in Belgium makes CDI/TCIs for various bikes. Probably worth a call to see if he could make a new direct replacement.

https://www.hpi.be/cdi.php

[Guest raghav]

Hi

I have a 1989 GS500. 

Its CDI is to be replaced. I am finding used CDI online. 

There is a confusion about reference number. I can see BB1225 written in white and a number below it on my CDI.

The used part I am getting is also BB1225 but the number below seems to be different. 

 

Does that matter?

 

thanks!!!!

 

[Gixer1460]

Reading this again and from the OP post - a CDI / TCI / ECU for a 4 cylinder engine won't work - properly - with a 2 cylinder engine. Well not without some clever / dodgy rewiring. So buying a 550 or 750 unit would be pointless!

[Suzukian]

If the bike has a kick start on it, there's a electrolytic capacitor in there. It would be nice to be able to make a plate, and use a Mallory Style pick up to fabricate one of these things.  I've seen customs ones in the U.S. (The land of the used to be free) but they are in the $600 buck range.

[gorbys]

My gsx engine didn't come with the cdi. So I swapped to a points setup but with a dynatek ignition plate. Then the dynatek failed and I'm now fully running points ignition. Which I will replace with a electronic ecu and vw tower coil in the winter. 
 

[Gixer1460]

How did you 'run a points set-up' with a Dyna S plate? Its a self contained unit - it gets fed power / ground and has outputs to trigger coils . . no points involved? 

[gorbys]

10 hours ago, Gixer1460 said:

How did you 'run a points set-up' with a Dyna S plate? Its a self contained unit - it gets fed power / ground and has outputs to trigger coils . . no points involved? 

On a later bike with electronic ignition advance you need to swap over the mechanical advancer from a early points style bike

[Gixer1460]

10 hours ago, gorbys said:

On a later bike with electronic ignition advance you need to swap over the mechanical advancer from a early points style bike

What's written still doesn't make sense! 

A later oem 'electronic advance unit' uses fixed pick-ups - like on GSX1150's. A Dyna S system needs the mechanical ATU fitted to 'non electronic advance' / dumb CDI's - eg. GS's & early GSX11's. A Dyna S needs no other CDI box to work, just like a set of points - they are wired direct to the coils. 

You can use a Dyna S backplate and pick-ups without an ATU - for race applications - it'll have fixed timing so relies on other add on boxes to adjust that, and should be linked to a Dyna 4000. Another downside is it really requires an 'off-board starter' to spin the motor up as trying to light an engine with 35 degrees of advance at 400 rpm ain't going to work with an oem on-board starter!

[Suzukian]

You can swap the whole points unit, make a plate to mount it too, and you now have your advancing points. Easy to do, with a little patience.  A great post apocalyptic trick if someone blows up part of the world.   (No EMP problem)