Testing cdi and pickups

[Captn]

Hmm, resistance should have been smooth. Maybe 150 to 450 ohms??  

[Captn]

This sucks @wraith.  Since I dont have the book, any numbers on resistance or pulsing voltage would be incorrect at this point. Sorry.  I had this same issue on my 750 and went through 2 CDI boxes off of fleabay. Pick up was good but the transistor for cyls 2 and 3 inside the CDI box would not conduct.  I tossed the whole Suzuki system and installed a complete Dyna system.  OEM cdi box was more expensive than the Dyna system, decision made, never looked back.  I'll get you some hard numbers tomorrow.  For now just verify ignition coil resistance for both primary and secondary windings. Verify 1 ohm or less of resistance between CDI plug black wire to chassis ground point.

[wraith]

This the reading before I turn the engine over, when I turn the engine over its all over the place from 80 up to 190

I will go and check the last bit 

I've got a slabside CDI, pickups and atu rota so may stick that on just to see if I get a spark 

Got a Dyna 2000 on the kat and never had problems with.

[Captn]

That looks good.  The resistance is changing during cranking because it is generating a signal. Looks like pick up is good. 

[Captn]

Also.  Look in the CDI sockets and the plugs to make sure there is no corrosion on the tabs and slide terminals.  Since they are copper they will corrode when the protective tin plating gets scratched off. The terminals will oxidize with a bluish green color and fail to conduct properly. This happened to my 1127 and it had to be trailered back home. If you see any corrosion,  scratch/file it off until clean. Coat tabs and slide terminals with dielectric grease and plug back together. Dielectric grease is our friend.

Edited April 11, 2020 by Captn

[wraith]

When you say check the black wire from CDI plug did you mean the black/white earth or black/yellow to coil?

The b/W has 00.3 ohm the b/y dose not read.

[Captn]

Yes. B/W wire to earth. Sorry.

[Captn]

Perfect continuity.  That's a great ground.

[wraith]

Ok it's sounding more and more like the CDI box. So I will swap the slabside ignition system on and see if I get a spark l will let you know how I get on 

Thanks.

[Captn]

Outstanding. I agree. All checks point to CDI. 

[Rake]

Hi all, good thread. I’m having similar issues  on my 1989 GSXR750.

when connecting a test bulb to the coil wires - no pulse. Change CDI to a spare and then get a pulse ok but still no spark.

testing resistance on the pickup wire is 171 ohms when not cranking and flickering open circuit when cranking. No resistance.

I do have 12v on orange at the coil. All wires between coil and cdi have continuity.

B/W to chassis is 0.3 ohms.

so is the open circuit while cranking at the pickup connectors pointing to the pickup being faulty ?

[TonyGee]

if you are getting a pulse at the ign coils then it sounds like the pulse coil is sending a signal to the CDI and then on to the ignition coils !!!!   have you tried new plugs ? 

[Rake]

On 9/26/2021 at 6:09 PM, TonyGee said:

if you are getting a pulse at the ign coils then it sounds like the pulse coil is sending a signal to the CDI and then on to the ignition coils !!!!   have you tried new plugs ? 

Hi Tony - sussed it out - no pulse from CDI so tried another CDI - got spark. Many thanks !

[TonyGee]

45 minutes ago, Rake said:

Hi Tony - sussed it out - no pulse from CDI so tried another CDI - got spark. Many thanks !

happy days 

[Rake]

On 9/29/2021 at 4:37 PM, TonyGee said:

happy days 

Not quite - the problems continue