The bike: 2011 990 Miles: 7642 No F1 codes So a buddy comes down to go for a ride last weekend, we head out on 2 fine running Adventures. No signs of problems and up to this incident, no issues of any kind. We get about 6 miles from the start and his bike just dies mid RPM at maybe 40 mph. Go through the regular check list, lots of head scratching and attempts to start the bike later I go and fetch the trailer and bring it back to my garage. Seeing as he was close to the time for a valve check, I tell him to leave it here and I will tear into it and see what I find. The short of the story is this: -Blow back into the oil tank, and I mean when cranking can feel the blow on each compression stroke comeing through the tank fill. -Check the valves and all in spec -No signs of anything ugly in the oil Now the other rub is when doing the valve check I had rags blocking the plug tubes, plugs out. The front cylinder religiously blows the rag out when rotating the crank on compression stroke. The rear however, nada. On the compression stroke there is no discernible air shooting out- I could really use the wealth of knowledge on this forum and will be most grateful for any and all insight. Unfortunately there isn't a KTM dealer worth a damn within hundreds of miles. I'm in South East Georgia near Savannah.
You need to get a compression tester and check the compressions properly. What state were the plugs in? Was the back one a different colour than the front? It could also be the immobiliser so check for a spark. In fact have you done the basics? Fuel present, usually a wet plug. Spark Then get into valves and compression etc. If it looks like fuel check the pump and filters. Steve
Even if one cylinder was fucked up it would still run. You didn't mention fuel. Is it out of gas? Kill switch? Side stand fucker. fuel pup/ filters all the easy stuff first.......
The plugs looked good. It did look as though the rear cylinder was running a little rich from the looks of the inside of the throttle body and intake. Yes fuel is present. I didn't check for spark, so once back together will get onto that and the immobiliser.
Fuel is good. Will it still crank if its the side stand switch? My understanding was the bike would not crank if sidestand switch or immobiliser were the issue.
So is it an electrical issue or a mechanical one? (You mentioned it just "died"...) - Does it tune over? - Are the battery leads connected firmly? - Is the battery good and charged? - Gauges lighting up ok? - Fuses? Just looking for the easy solution first. Q~
Could the fuel line not have been completely together at the quick connect? If he has had the tank off recently could be the culprit.
BIG WARNING ABOUT RAGS IN THE SPARK PLUG HOLE!!!! All of a sudden it sucks the rag down into the cylinder, a piece of steel wire bent into a hook and quite some time fishing it finally came up but that was on a machine with the spark plug hole a lot easier to access then the deep abysses they have on the LC8 engine. Might have posted this previously in the "Note to self" thread over in the garage section. /Johan
All electrical checks out fine, cranks like a champ, goes through its usual start up procedure, but just cranks and cranks, no fire. Fuses are good too and it has spark. As dgjackson40 suggested, it could be the fuel line quick connect. The tanks had been off days before. But that wouldnt explain why it blowing back into the oil tank. I have checked the crank case breather and all good as well as the oil return lines going into the tank. Will be doing compression test and leak down tomorrow, but the more I think about it, the more I am thinking its a kinked or clogged line somewhere. He also had a slow speed get off a couple days before, so was thinking maybe something to do with fuel in the canister . I dont know if that would cause these kinds of symptoms or not. It has obviously been running rich too, so would it be possible to have such a degree of carbon build up that a valve not seat properly? I am really grasping at straws, there are so few miles on the bike I cant imagine it being a ring issue and there is no sign of any metallic debris anywhere. I do appreciate the suggestions and insight, please keep it coming. DirtyADV: Good call, all orifice are now sporting latex gloves - Lycan1: Its possible, I know the filters have never been changed. Will pull the fuel pump and visually inspect. The only reason I didn't yet was because of the other symptoms, particularly the blow back into the oil tank. Thanks again everyone-
So after compression check and leak down show nothing of concern I decided to put it back together. Low and behold its running great, though a little rich still so it will be getting re mapped this weekend. Any suggestions on a map? Has Lexx pipes on it and still has canister etc. I am not sure what the original cause of its problems could have been. I did notice when I changed the oil that it appeared to be more oil than I see when I change mine. (same bike, but a year older) So I decided to measure it and there was 4400+ mils. Wonder if this could have caused the upset or a blockage somewhere? In any event, remap this weekend and off he can go so I can get back to floggin my beast.
Try the powertripp maps out. ( http://www.tuneecu.com/KTM_Tune_list.html ) Also check the ignition wires where they go into the frame. It is very common to have those wires break and cause random dying issues. You can kind of see where they get pinched. I just shit canned that black plastic cover completely. The 950's didn't have it and the only reason it's there is to prevent tampering with the alarm.
The downstream, female, side connector on that cable only has two pins. Poke a jumper in there, and the bike should power up as if the key is switched on. Something to remember if you ever lose your key, or see a suhweeet 990 you'd like to ride. Just kidding, really.<J k>
Engine needs three things to run. Fuel, spark and air. All other bells and whistles on the bike such canisters and immobilizer... Cut off or mess with one of the three elements. It's not too difficult to check for each. If you have fuel but no spark you will smell strong gas fumes from the mufflers after trying to start couple of times. No smell? You can disconnect the fuel line going to carbs or FI and see. Work your way back from the cylinders. 990 has a lot more fuel pressure than 950, so watch out. Be ready to hit the kill switch. Spark is easy too, just pull one spark plug and see. You can even avoid removing the spark plug itself. Pull the plug and stick a wire or screw driver in the plug coil then keep it close to the body of the bike. You should see spark jumping to the body. 950 and 990 have the coil which increases the voltage a lot right on the plug. So just disconnecting the wire at the top of the plug won't help unless you have voltmeter or an LED light. Air is easy. Very very dirty filter?
