15 ktm 500 exc starting/running problems

[leland]

Probably full blown my fault but having trouble now at this point. I took the bike out for about 30 miles the other night completely stock other than the screen on the exhaust knocked out and air valve plugged with tape. Now last night I desmogged it and noticed a bogging off quick throttle. Let it sit and idle like I read and left it at that. Today I took it out and couldn't make it to the end of my street without it dying, so I had to start it with some throttle and turned around and came home. I adjusted the idle up a little more and made it a few miles. Turned it off, started it back up fine, did some stoppies on it, turned it off checked my phone, took off again and made it about a mile before it started stuttering on itself and died. Started it with some throttle again and made it about a mile before slowing down to a stop sign and it died again. Was able to get it started again after 10-15 minutes with some throttle again and made it about another mile. After that I had zero luck getting it started and had someone bring me my truck to load it up. Got it home, pulled the tank and checked to make sure everything was snug. Messed with the idle every which way and could only get it to start for a split second every now and then and then it would stumble and die. Searched here to see if anyone else was having this problem and recommended going somewhere between 9-12 clicks from full counter clockwise on the idle. Still no go. Pulled the spark plug and cleaned it just because and got it to start for maybe 30 seconds to a minute. Then back to not starting at all again.

Have not done anything else to this bike other than cosmetic and a master cylinder. Have not messed with the tps, I bought it used from a dealer. Pulled the little fuel filter, looked clean. Just looking for some ideas maybe. I'm new to ktm's. Thank you guys

[OlaGB]

Just to start with; double check battery connections. There has been several threads of bikes not running correct, that has been due to battery connections.

EFI lamp isnt blinking after starting it?

Dont do changes to tps unless it has come loose. Its only going to confuse youre faultfinding.

[shannon cone]

Just had a brand new 16 have a bad fuel pump. Open gas cap and if u can get it to fire crack throttle a few times and see if gas splashes basicaly u jn the face. If so have a cracked line in there. Just saying can't hurt. And just had it happen.

[oldfuddy]

Turn the key on until pump stops and then turn key off. Then disconnect the fuel line QD and see if fuel under pressure comes out of the motor side (not tank side) of the line? Heard of QD's going bad or not engaging all the way. Just something else to check.

Edited November 19, 2015 by oldfuddy

[sirthumpalot]

Fuel issues is high on my suspect list. As mentioned above, check for good fuel pressure, and check the inline fuel filter in the disconnect. Also make sure the battery leads are tight, of they come loose it won't run.

[leland]

A friend brought his fe501s over and suspected fuel issues as well. We went through everything. Finally pulled his tank and hooked it up to see if it had anything to do with my fuel pump and had the same results. Pulled his battery, same results, ecu, same results. I ended up pulling the spark plug back out and he noticed a hairline crack on it. Ran to the store and got another and now it runs again.

Edited November 19, 2015 by leland

[desertkatoom]

+1 fuel pump. One of my buddies brand new 2011 SX-F 350 had same symptoms. It runs fine until the pump heats up, stutters and dies. Let it cool off for 10-15 min, run until pump gets hot.

 

If you have to get your own, check out CA Cycleworks. Not sure if they have them for the 15's but he has had zero issues since and it was ALOT cheaper than stock.

[Burnrider]

_{What brand spark plug?}

[leland]

_{What brand spark plug?}

 

ngk

 

[Spud786]

That's a real fluke,  and rarity,  Id lay odds it was dropped it or someone cracked it on install. over actually being a manufacturing defect..

[Burnrider]

That plug looks old, but it's a '15. Great detective work on your part. I'm with SPUD. Champion used to be the worst quality plug in the world. NGK has always been really good. Never cracked an insulator like that so I wouldn't know how an owner could do that.

Edited November 20, 2015 by Burnrider

[Mikek671]

A friend brought his fe501s over and suspected fuel issues as well. We went through everything. Finally pulled his tank and hooked it up to see if it had anything to do with my fuel pump and had the same results. Pulled his battery, same results, ecu, same results. I ended up pulling the spark plug back out and he noticed a hairline crack on it. Ran to the store and got another and now it runs again.

This same thing happened to my old 2012 I sold to a friend, we were out riding and the bike started running like crap.  Got to a point where it was misfiring and eventually would only idle for a short time, pulled him back to the truck and tore it apart - crack in spark plug ceramic!

 

New plug in and it ran better than ever, it was a stock NGK that cracked and only had about 10 hours it.  It happens for sure!

Edited November 20, 2015 by Mikek671

[sirthumpalot]

Mental note, start carrying extra spark plugs!

[Ud_Luz]

Mental note, start carrying extra spark plugs!

I'm amazed, I thought everybody did. 

[sirthumpalot]

I usually keep one in the tool box, but never had a need to carry one on rides with the 4 strokes. Got to get one for the toolbox now, been lazy about that with this bike, oops!

[oldfuddy]

Is it just me or does that plug look old? I know I'm in the desert where it's dry, but mine would get changed long before looking like that.

[RideFreak]

Yours is about the 4 one of these I've heard of.  KTM must have a step in the assembly process that stresses the porcelain on the plug. 

[sirthumpalot]

Vibrations will do it. I had a weed whacker that would crack plugs about once a year. Champion plugs, but none the less..

[cadman_ks]

That crack is black, so that indicates to me that it's been there for a while. If it was freshly cracked, I wouldn't think that the dirt and stuff would have gotten in there.

As for "old" looking, that's what mine looked like my '14 when I took it out at 60 hours. I think some of that comes from water getting in there when you powerwash and go thru water puddles, and then makes the zinc coating on the plug oxidize...

[Ud_Luz]

That crack is black, so that indicates to me that it's been there for a while. If it was freshly cracked, I wouldn't think that the dirt and stuff would have gotten in there.

As for "old" looking, that's what mine looked like my '14 when I took it out at 60 hours. I think some of that comes from water getting in there when you powerwash and go thru water puddles, and then makes the zinc coating on the plug oxidize...

You seriously don't power wash your FI KTM do you? 

 

If you're going to do so then take apart every connector, fill with dielectric grease and reassemble. These bikes REALLY don't like any moisture in the connectors.