DRZ400S Missing when Hot

[bossche]

I have a DRZ400S with 22k Miles on it and it started miss firing or hestitating on the freeway when cruising at about 60 MPH once it go warn (about 15to 20 minutes of riding). It was almost like the kill switch was being flicked on. It has been getting worse and not once it is up to full temp it misses in a larger range of about 1/3 to 1/2 throttle under load. In neutral is done not miss.

I tried cleaning out the carb, ended up replacing he float value seat and resetting the float level, that did no t fix it.

Replaced the coil and spark plug wire think that that may be shorting out once it got hot.

Neither of these changed anything.


Has anyone run into this issue before and have any suggestions?

 

[ktmken]

Check your side stand safety switch and your clutch safety switch.
Your comment about "like the kill switch being flicked on" suggests that it could be one of these safety switches.
Good luck

KTMKen

(On my drz sometimes the heel of my boot would push the side stand down while riding and that would kill the engine for a split second)

 

[Shuswap]

Sidestand cut-out is a known ignition interrupter, but usually over rough undulating ground. Mine was eliminated by the previous owner

 

[snackdaddy]

I would look into testing the stator and the pick ups. I think the test procedure is on thumper talk somewhere. IIRC One of the pickups advances the spark. You may be getting some signal from that pick up but not all the time. If you do need a new one I highly recomend rm stator in quebec. Cheap, qualitly and fast shipping if you are willing to pay.

Good luck

 

[bossche]

The side stand switch was removed a number of years ago.
I had rep[laced the stator with an RM stator when the original started to output low voltage but that is a good point and will check it.

 

[vortexman]

I have a DRZ400S with 22k Miles on it and it started miss firing or hestitating on the freeway when cruising at about 60 MPH once it go warn (about 15to 20 minutes of riding). It was almost like the kill switch was being flicked on. It has been getting worse and not once it is up to full temp it misses in a larger range of about 1/3 to 1/2 throttle under load. In neutral is done not miss.

I tried cleaning out the carb, ended up replacing he float value seat and resetting the float level, that did no t fix it.

Replaced the coil and spark plug wire think that that may be shorting out once it got hot.

Neither of these changed anything.


Has anyone run into this issue before and have any suggestions?

When I was racing in the 80’s we would follow a certain diagnosticroutine to find faults and rule out components or systems quickly. We would usea small propane bottle and introduce propane into the air box. This quicklyruled out problems in fuel charge and induction leaks.

Next step was a warm engine compression test followed by aleak down test. This quickly eliminated any doubts with regard to piston,rings, valves or head gasket integrity. Gasoline powered ICE engines require aminimum of 100 PSI to initiate and complete efficient combustion.

Schematics were consulted and battery tested as well asalternator output. Then all power and ground connections at battery , CDI ,ignition coil were tested for integrity and voltage drop.

The schematics also indicated any safety switches that wouldbe by-passed to rule them out as the problem (side stand switch, ignition killswitch the being two big offenders). A dual trace lab scope would be connectedat ignition coil to confirm CDI function and source voltage spec.

In severe cases pulse coils were tested but this can notalways be carried out in-situ and in some instances stators and CDI modulesmust be changed out to confirm correct function.

This is a last resort. If you have schematics and a drygarage I am free in a month but I can recommend Motomethod. The guys there arequite good.

JT

 

[bigmac]

I have a DRZ400S with 22k Miles on it and it started miss firing or hestitating on the freeway when cruising at about 60 MPH once it go warn (about 15to 20 minutes of riding). It was almost like the kill switch was being flicked on. It has been getting worse and not once it is up to full temp it misses in a larger range of about 1/3 to 1/2 throttle under load. In neutral is done not miss.

I tried cleaning out the carb, ended up replacing he float value seat and resetting the float level, that did no t fix it.

Replaced the coil and spark plug wire think that that may be shorting out once it got hot.

Neither of these changed anything.


Has anyone run into this issue before and have any suggestions?

You never mentioned changing the spark plug, I would!!

 

[Shuswap]

Any success with this yet, Bossche?
Hate to see a fella sidelined with this perfect weather and these issues aren't all that difficult to sort out