2011 Kx 250f Efi mystery problem

[marcavella11]

Bought the bike off a friend with a bogging issue thinking it would be an easy fix..

At first thought it was running lean , cleaned injector , fuel pump filter. Still the same. Changed plug, fitted a brand new tps sensor after reading many issues about them , got ECU checked by a bike shop who said there was nothing wrong on the bike electrically . Ran fresh fuel . Tested fuel pressure , seemed a bit low under acceleration , changed fuel pump , pressure better but still bogging while accelerating and backfiring when decelerating . Found that intake valves were leaking , did a full bottom and top end rebuild with new valves . Bike starts easier now but still bogs and struggles at high rpm and won't hit the limiter . I have given up now on trying , valve clearance good, cam timing good . If anyone knows anything else I may have missed ? Would really like to go and ride

[4Sevens]

Check the sensors.  Can't remember which one(s) were problematic.  There are threads on here.

[kawagreen4life]

I have the same bike 11 kx 250f same problem u have would not hit rev limiter back firing the of piston very very clean put all new valves seat everything new now bike turns on but can't touch throttle or it will die it will stay running for 10 15 seconds n it dies and it won't start again for hours. I have another 11 swapped all electrics and nothing. If u get it running rite pm me with what u find thx

[m78val]

try rotating vehicle sensor 180 degrees, sometimes they get puuled out and put back in up side down

[marcavella11]

Thanks , il give that a try

[marcavella11]

No luck..

[m78val]

^{double check cam timing}

[marcavella11]

I have done that and confirmed it with a bike mechanic.. I am now leaning towards it being one of the air temp , pressure sensors or water temp sensor. Although bike shop already checked for error codes and found none . Tps is brand new and has been set properly.. The last thing would be my injector that was cleaned and tested . It works but has a V shaped spray pattern. Don't know if that's the norm?

[marcavella11]

Just rode it for a bit today and it just died. Took the spark plug out and grounded it to the frame and kicked a few times. There was no spark .. Also checked with fuel pressure gauge and the pump was pumping intermittently as well as the spark plug was sparking weak and intermittent and sometimes good.. What could this be ? Stator or condenser?

[pepe001]

Had the same after rebuild!

 

Turned out that the cap assembly from coil to spark plug was broken!

 

Had a spark and the next minute nothing.

 

Bought a new coil and cap assembly for $70 and everything is fine!

[marcavella11]

Just tested the system by connecting a 12v battery to the regulator/rectifiers output wires. Fuel pump came on constantly . Therefore I think I have narrowed it down to either the stator or the regulator /rectifier not giving enough voltage to the system as neither the fuel pump or spark was working properly while kicking it over

[marcavella11]

Had the same after rebuild!

Turned out that the cap assembly from coil to spark plug was broken!

Had a spark and the next minute nothing.

Bought a new coil and cap assembly for $70 and everything is fine!

Was this on a 2011 model?

Edited June 30, 2016 by marcavella11

[pepe001]

Yes it is a 2011.

 

Was crazy one minute is was ok the next minute it didn't work.

 

checked the spark and it was the same sometimes yes sometimes no.

 

Changed the coil and cap assembly and everything is good now. 

 

Don't have any issues at all.

[marcavella11]

Yes it is a 2011.

Was crazy one minute is was ok the next minute it didn't work.

checked the spark and it was the same sometimes yes sometimes no.

Changed the coil and cap assembly and everything is good now.

Don't have any issues at all.

Thanks for the response , I have ordered a new ignition coil but not the cap. Hopefully that's the problem.. Glad to hear that these problems do exist with Kawasaki as the bike shops I have spoken to said they have never replaced ignition coils on a 250f.

[pepe001]

It will be most likely the cap!

 

At least that's what I had, tried 2 coils and had the same with both.

If I looked at the cable which will be screwed into the coil, it looked corrosive really bad.

 

I think that's mainly the issue!

Bad contact from Coil to cable!

 

I cleaned everything and used some W40 to clean it up.

result it was working for a short period of time.

 

You might can try it.

Take out the Cap assembly apply a little W40 clean it an but the cable back in. 

 

If it works you will have the issue.

[marcavella11]

It will be most likely the cap!

At least that's what I had, tried 2 coils and had the same with both.

If I looked at the cable which will be screwed into the coil, it looked corrosive really bad.

I think that's mainly the issue!

Bad contact from Coil to cable!

I cleaned everything and used some W40 to clean it up.

result it was working for a short period of time.

You might can try it.

Take out the Cap assembly apply a little W40 clean it an but the cable back in.

If it works you will have the issue.[/ quote]

Thanks il definitely give that a try!

Will let you know if I come right ..

[marcavella11]

Still struggling , got a brand new coil and cleaned the contact to the plug cap all reading fine with multimeter . Bike still doing the same . Starts up runs for a bit , then backfires and dies. No more spark after it dies.. Checked crank sensor resistance when there was no spark and it was within range too.. Could this be the Ecu then? This is the most frustrating problem I have ever had on any machine in my life

[tmsuspension]

Test stator next

[kawagreen4life]

Check the cylinder it may be damaged

[roddytrucks]

Disconnect the kill switch