intermittent cutting out!!

[CRH]

earlier today went out on foxeye, did just over 60miles!..didnt miss a beat!!..mainley cruising speeds...odd couple a times up to red line!! ran perfect!!!...on the way home came across a line of slow moving traffic!..so went for a overtake..2nd,3rd,4th,..then,,, ...complete cut out as if ide hit kill switch!!...as luck had it i had just about completed my pass,but found myself level with a 6 wheeler!! ...of which i just managed to slip behind!!....anyway i managed to coast into a layby..sidestand down ,shook the shit out me trouser legs and litt up a fag!!....5 minutes later i had a quick look over it,chkd fuel etc, switched it back on and>>>>>>>started up and purred away like nowt had just happened!!!.....so set off again no probs!!...took it up to 60 without any glitches!!..plenty of power etc!!....then fk me    did it again!!...but this time it wouldnt start !!....waited for about 15 mins tryed again and this time it started!!....got back home bt hour ago!! had another look over it ,chkd fuel pump that seems ok!!...chkd wiring plugs etc they all good!!  only thing i did find was the ecu was very,very hot..dont know if this is normal or not??...but it started again and this time i lett it run till fan kicked in and didnt cut out at all any ideas???????????

[red98]

oh no....here we go,the start of another epic thread  .........instant cut out points to electrics in my mind,"ecu getting hot".iam sure theres just a pcb in the black box so should not get that hot.....if it was fuel pump you would have got a little warning before it cut out  .......i`ll run my 600 tomorrow and see how hot the ecu gets.have you had the tank and side panels off to check all connections ?

[CRH]

hi paul,...got tank off now as we speak!!...cant find anything amiss under there!!...got t agree with you though?...does seem electrical doesnt it?...no warning at all...scary moment there matey? ....trouble is it wont fkn do it now?...went up n down our lane b for i took off tank and it ran perfect again!!...but this ecu is fkn scortchin hot!! ....have ran it for 3wks without any glitches ran lovely !..so think whatever it is its on its way out?

[Paul]

I'm surprised your ECU is still working if it's getting that hot.

Have you checked the voltage across the battery when the bikes running?
It should be 15 volt.  If it's a lot more maybe the voltage is not being regulated properly.

Or may be excess current is not going to earth.
And you've got excess current going through the ECU to get to earth.

Check the earthing of the regulator/rectifier and the connections to it (finned bit close to the head stock under the tank)

I caveat all the above with (I'm not that good on electrics).


 

[CRH]

I'm surprised your ECU is still working if it's getting that hot.

Have you checked the voltage across the battery when the bikes running?
It should be 15 volt.  If it's a lot more maybe the voltage is not being regulated properly.

Or may be excess current is not going to earth.
And you've got excess current going through the ECU to get to earth.

Check the earthing of the regulator/rectifier and the connections to it (finned bit close to the head stock under the tank)

I caveat all the above with (I'm not that good on electrics).


 

..hi just chkd that and ime getting 14.6...with lights off and 13.5 loaded up?.....have chkd connection to rectifier and that was ok!...but that is also very hot but seeing its got cooling fins on it think that may be normal?

[Paul]

Have you tried revving the engine and seeing what the voltage is?


It should remain at up to 15 volt.  If it goes higher, then the regulator isn't working properly.


I don't know how hot either the ECU or the regulator/rectifier should get unfortunately.


Often when a bike cuts out like yours has, it's a 'short' from live to earth or a poor connection.

[red98]

not too good on electrics either as you know  ....all electrics are going to generate a bit of heat and i like your reasoning with  the regulator......battery terminals tight ?,you`ve probs already checked that.....good excuse to get out on it and try and replicate the cut out,take your multimeter with you for some roadside checks  .

[red98]

got me thou with me at work today,going home shortly so will see how hot the ecu gets.....

[CRH]

got me thou with me at work today,going home shortly so will see how hot the ecu gets.....

....thanks for that paul!...one to cross off the list hey?...hope t fk its not going t b one of those ...????/ er best/worst seller times again? .....

[red98]

sure it wont be matey....probs something simple that you will find when your not looking for it....if that makes sense 

[red98]

thinking out loud.....the ecu is well inclosed in the tail unit.if its normal to get hot i think mr yamaha would have mounted it elsewhere......just a thought 

[CRH]

Have you tried revving the engine and seeing what the voltage is?


It should remain at up to 15 volt.  If it goes higher, then the regulator isn't working properly.


I don't know how hot either the ECU or the regulator/rectifier should get unfortunately.


Often when a bike cuts out like yours has, it's a 'short' from live to earth or a poor connection.

...reving engine without any loading ime getting 14.85....with load.....14.2....thats reving it up to 4k..

[CRH]

thinking out loud.....the ecu is well inclosed in the tail unit.if its normal to get hot i think mr yamaha would have mounted it elsewhere......just a thought 

...mmm hope so paul?....lets hope thers not a fazer virus in the air?....dont think i could go through all that again?

[red98]

ok clive...just got in......ecu is only slightly warm,hard to detect,why it would get so hot i dont know.......someone with electric knowledge will be along shortly   

[CRH]

ok clive...just got in......ecu is only slightly warm,hard to detect,why it would get so hot i dont know.......someone with electric knowledge will be along shortly   

....thanks for that paul?...so mine sounds a bit iffy then" dont you think?.....in these situations you wish it would just pack up n be done with it dont you?...fkn hate shit like this!!....going t go out on it tomoro and get my lad to follow me t see what happens?...ile take me meter with me n see if i can trace it?......

[red98]

oh that would be too easy  ..........got a spare ecu here somewhere if you need one,i`ll be surprised if yours is faulty though 

[CRH]

oh that would be too easy  ..........got a spare ecu here somewhere if you need one,i`ll be surprised if yours is faulty though 

....yes it would wouldnt it?.....thanks for the offer paul....ile keep thee posted ....had it running again earlier for a good hour!!....didnt miss a fkn beat ,,,,and within 15mins the ecu was red hot again??....dont know what t think?

[red98]

mmmmm....dont  know what to suggest.was hoping a sparky would have come along by now ...

[unfazed]

I would suggest you lift the tank and open the box with all the connectors in it. Take them apart one by one and check them for corrosion. Dose them with WD 40 instead of contact cleaner as it leaves a film which prevents further corossion.
A common problem is for the red block with 2 connectors in it to show signs of burning due to arcing and is the main 12volt wire from the ignition. This can often lose contact causing the bike to cut out temporarly due to the corrosion and vibration.
 

[midden]

rover 400 would do the same and that turned out to be rotor arm failure or more the diode that it contained. I know bikes don't have rotor arms but does the rotor it have a diode or maybe the condenser

[midden]

It only ever happened on really hot days as well

[CRH]

I would suggest you lift the tank and open the box with all the connectors in it. Take them apart one by one and check them for corrosion. Dose them with WD 40 instead of contact cleaner as it leaves a film which prevents further corossion.
A common problem is for the red block with 2 connectors in it to show signs of burning due to arcing and is the main 12volt wire from the ignition. This can often lose contact causing the bike to cut out temporarly due to the corrosion and vibration.
 

....cheers for that unfazed!...ile do what you suggest and see what happens?..it must be something like that to cause the ecu to get that hot surely?..i went in me garage at 5am this morning whilst everything nice and cool? started her up ,ran to temp ,but again within 15 t 20 mins the ecu was untouchable!!....but as before it still" didnt cut out!!!!....

[CRH]

It only ever happened on really hot days as well

...yes you may be on to something there midden?...i did notice i had to let it cool a few mins before it would start?....

[Paul]

To CRH


If it's that hot there's too much current going through it.


Therefore it is likely that something is allowing current to go to earth after it's been through the ECU.


A short circuit of sorts.


Stab in the dark, but, the wiring is subject to the most stress through movement when it exits the frame and goes to the steering head.

[CRH]

To CRH


If it's that hot there's too much current going through it.


Therefore it is likely that something is allowing current to go to earth after it's been through the ECU.


A short circuit of sorts.


Stab in the dark, but, the wiring is subject to the most stress through movement when it exits the frame and goes to the steering head.

...thanks for that paul!..you could be right there matey?..seems its only going to do it when ime on the move?...like ive said it wont bloody do it stationary!!..going to strip the lot down today and see what i can find ...