Gsxr 400

[faantjie62]

Gk73a

Sent from my SM-J100H using Tapatalk

[faantjie62]

Hi guys.need some advice please.i have a gk73a.getting good spark on all 4 plugs but its a constant spark even by just turning the engine a little bit and my coils and cdi gets hot in seconds.i checked my wires and coils is fine.any idea what it might be?dont think it will be the cdi because its almost brand new.

Sent from my SM-J100H using Tapatalk

[ventYl]

You get constant spark on all of plugs? The CDI's CPU is probably faulty or some circuitry around timing wheel is broken. Coils are getting hot because of excessive amount of current flowing through them. If coils are getting hot but you don't get any spark then CDI short circuits coils which makes them hot.

[faantjie62]

Thanx for the advice.yes theres constant spark even when the engine turns for a split second.coils get so hot that after 5 min i cant touch them anymore and to me thats not normal.i know that it will be hot but not that hot.

Sent from my SM-J100H using Tapatalk

[ventYl]

you can try to check pickup coil wiring as per workshop manual but I don't give it high hopes. It looks like the CDI is faulty. I don't se any other reason for constant spark to appear.

[moforockband]

what happens if the cdi is disconnected?

[faantjie62]

So i disconnected the 2 pickup coil wires and still getting very hot.disconnected the coil wires only and the cdi stays cold.

Sent from my SM-J100H using Tapatalk

[SevenThreeSeven]

So i disconnected the 2 pickup coil wires and still getting very hot.disconnected the coil wires only and the cdi stays cold.

It sounds like you've got a wiring problem. Has somebody (a prior owner) messed with the wiring? The only thing that will make the coils get hot is 12 volt power flowing through them. From your description it sounds like there is a constant 12 volt power flowing through your coils whenever the bike is key-switched to "ON".

It sounds like your coils have a constant path-to-ground connected to them. Either there's an external wiring problem, such as accidentally having the coils physically wired to a path-to-ground, or having an improperly wired CDI connector plug or a defective connector plug that is allowing a constant path-to-ground.

The coils aren't designed to handle constant 12 volt power flow. In normal operation the CDI will "charge" the coil (by providing a path-to-ground) for only about 2.8 milliseconds before firing it. So, even when the GSX-R400's engine is operating at it's redline speed (14,000RPMs) the coil is only "charging" for about 65% of the time and it is "resting" and cooling the remainder of the time.

[faantjie62]

Yes i bought the bike with the problem.when i check my voltage going into the coil it shows 12v and comes out 12v so 12v goes through the coil back to the cdi but my wiring diagram shows my 12v wire coming from my cut out switch then splits up in 3 wires.1 and 2 going to my coils before 3 going to my cdi.is this correct?

Sent from my SM-J100H using Tapatalk

[SevenThreeSeven]

Yes, you have traced the GSX-R400 wiring diagram correctly: 12 volt power for the coils comes from the Fuse Box (Ignition fuse) and proceeds to the Side Stand Relay. If the Side Stand Relay is "triggered" by the side stand switch then 12 volt power is proceeds to the Kill Switch. If the Kill Switch is set to "Run" then 12 volt power proceeds to #1 and #2 coils and to the CDI box.

Yes, you definitely want to make sure this wiring is correct on your GSX-R400, but I'm pretty sure it is because otherwise the coils wouldn't have the 12 volt power necessary to cause the overheating problem you're describing.

Your problem is not a 12 volt power supply issue, it's an improper path-to-ground problem.

The normal constant 12 volt power that is supplied to coils (whenever the Side Stand Relay and Kill Switch conditions are met) will simply rest on the coils doing nothing at all until something provides a path-to-ground for that 12 volt power. When a path-to-ground is provided the 12 volt power will flow through the coils which charges them up for discharge (firing the spark plug).

As I mentioned earlier the CDI normally only provides that path-to-ground for 2.8 milliseconds at a time, then it interrupts that path-to-ground which causes the coil to discharge through the spark plug.

Something is providing a constant path-to-ground for your coils.

You need to trace and verify the wiring for every single wire that goes into the CDI box. Check the condition of the wiring, look for exposed wiring or poorly protected splices.

And you need to inspect the CDI plug to make certain that the wires are all going to the correct pin locations on the CDI plug (to connect with the correct pin on the CDI box). If the prior owner messed with the wiring to this plug he may have put the pins back in the wrong order.

And you need to trace and verify the the two wires that lead to the bike's Pulse Generator.