Ongoing problem with GSXR. Please help!

[Neeli]

Hi guys,

Have been recommended to post on here by a number of good friends, who are all 400 fans like me. I hope you guys can help!

I have been basically scratching my head for the past 2 months with regards to my 1992 GSXR 400 GK76A, and have now ran out of options.

I bought it in August as a non runner for next to nothing, with view to getting it running and keeping it. It would turn over but not fire up. The first thing I did was have a look at the carbs. They were pretty grimey so I sent them off to be ultra sonically cleaned. They came back looking brand new and I fitted them back onto the bike. Same problem though - it would turn over but no start.

I checked for a spark and saw there was none, so I replaced all 4 plugs but still same problem.

I then worked by way back to the CDI box. After looking inside, I saw that it was fried . I ordered a new one from eBay (some guy in China manufactures them to the exact same one as yours if you give him the part number and B number). It arrived and I fitted it. AGAIN, SAME PROBLEM. Bike would turn over but not start. However, this time IT DID PRODUCE a spark. But only one spark, and that's it.

I have now also replaced the coils, but this has not fixed the problem.

When fitting the new CDI, I checked resistance and voltage across most the loom, and all was good. I have checked again today (2 weeks after fitting the newer CDI) and only have 1V running to the coils, when I know it should be 12V. (It was 12V when I fitted it 2 weeks ago but has now dropped to 1V).

Is something frying the CDI units? If so, what could it be? Or is there something I'm missing? I'm 95% sure it's an electrical fault somewhere.

There is no aftermarket kill switch anywhere and no aftermarket alarm or immobiliser that has been previously fitted as I can't see any non standard wires or connectors. Another friend said I could have dirty or corroded pick ups inside the pulse generator?

Any help would be really appreciated. I cannot face the possibility of having to break the bike as it's way too immaculate. But on the other hand, I don't want to be continuously throwing time and money at it and not getting nowhere. I'm in a Catch 22!

Many thanks. Ash.

[morris147]

Is the wiring correct for the coils?

I cant remember off the top of my head, but i will check later.

[Neeli]

Is the wiring correct for the coils?

I cant remember off the top of my head, but i will check later.

Hi Morris

Yes wiring is all correct. I've checked and double checked. Also had a very good friend, who is an auto electrician for Suzuki, to come look at it and he is as baffled as I am...

[Awynn]

CDI from 'some guy in China that makes them', your problems might be as simple as that!
If you have checked the resistance across the input side of your coils and your signal sender and they are ok then all I can think that could fry the CDI (assuming the chinese CDI was ever any good - big assumption btw) would be over-voltage. As the bike has not ran(correct?) you can rule out faulty Reg/Rec so have you maybe had a charger connected to the battery with the ignition on (power to the CDI) which could have produced too high a voltage and fried it?

[Neeli]

I've replaced the CDI unit today with original one that I bought from a breaker (that's the only way you can get original parts now).

But still having the same problem...

[Awynn]

Have you checked the resistance across the signal generator? I think it is the same as gk73, 100 Ohm +/-20%