Help.. XJ650 4KO cuts out exactly 40-50secs.

Help.. hi my XJ650 4KO cuts out exactly 40-50seconds after starting. bike has not been use for almost 1 month, this christmass morning problem comes my engine would start easy as if no problem whatever then out of nowhere engine dies like i turned of the ignition key.. carbs are 99.9% clean. im suspecting something ELECTRICAL but i don't know where to start? my ignition coil seems fine since the CUT OUT in power happen super fast.. and if i start it again, it would start just fine! what is happening??? lose wire? i check the fuses all OK. which wire do i check next? i pray its not the TCI box ☹️ thank you in advance guys n gals.

 

also i tried keeping the RPM steady at 2k RPM just to see if it would cut out or sputter... result is the same engine cuts out suddenly.. no matter what RPM i was in. this is one reason i think my carbs are Ok. also i have "some" fuel in the tank almost empty but still should not result in sudden cut out‍‍ Help please

 

Well, that isn't a nice present. It could be a fuel thing, try adding gas to the tank, simple enough. It could be just enough flow to fill the carbs to run that long, it uses it up an done. If it is better with more fuel check for a flow restriction such as debris on the petcock strainer. Good luck & Happy Christmas!

 

ok im doing this next... i sure hope it just fuel tnx sir.

 

Have you got an external fuel filter? If so you could bypass that temporarily. But l had a Suzuki GT 250 that was doing what your bike is doing but not after the same amount of time. It was a chaffed wire touching the frame the mechanic told me. Sometimes it would not start at all Because your bike is cutting out suddenly sounds like it's electrical to me too. Check all your electrical connections, side stand switch, clutch switch etc. I believe the TCI has two transistors one for each pair of cylinders so they cannot fail together l would think. Unless there is something in the TCI box that can prevent both transistors working intermittently it is unlikely the TCI is the problem.

 

update: wow i just found out a low fuel level can make may bike shutdown as if it was turned of like a light bulb, weird really i really thought it would sputter or stumble considering not all 4 fuel bowls are exactly 100% loaded with the same amount of fuel. well atleast i found the problem and avoided opening up my entire electrical wiring hehehhee i was already looking for a 2nd hand TCi box.. , 6liters of 95 octane (shell Vpower) stabilized my heart beat thank you everyone and have a blessed christmas! Ride safe!

 

thank you sir Fuller56 merry xmass!

 

That's great news! Truly a Christmas miracle!

 

Great it's fixed.

 

So glad it is fixed, well mostly. I bet there is still a fuel flow restriction somewhere. Just having the tank full gives it enough gravity pressure to get past the restriction. It should be pretty free flowing until empty. But at least you can use it and know how to work around the problem.
I was not discounting the folks that thought electrical issue though. The fuel flow problem is just way easier to rule out.

 

yes there was restriction in fuel line it self.. i change the hose to a clear hose but with a smaller inner diameter lessthan 6mm.. i will be correcting this error next..

 

i will use original sized fuel hose.. im 101% sure it was the culprit since it was the last thing i tinkered with before the "cut off" problem happened..