Experienced tech cannot figure out FI issues.

[fastline]

I have been working on FI for years and the 700 is a pretty primitive open loop system but it is sure beating me......   Friend of mine brought it by with a few issues.  I first checked valve lash and IIRC, I was about 7 and 9 on them.  Came in with failure to start, popping, etc.  Put a new plug in and fired right up but obviously both running fat as sh** and burning oil.  Plenty of blue smoke. 

After going through every single sensor with a fine tooth comb and deciding an injector might be hanging up, I replaced the injector.  No dice.  So I decided to go ream it's neck and I probably got 1-2 passes through the gears and it fouled the plug, started backfiring bad, etc.  Really acting lean but due to recent conditions, I bet on the plug.  I put a plug in and fired right up...  It obviously will not hold a plug but I have never seen a bike that smokes a bit kill a plug in minutes.  Something is seriously wrong here. 

I realize many will probably just point at the TPS but I am a man of testing and both resistance and voltage sweeps of that sensor are flawless.  It was even shock tested while under test.  I assume it could be possible that engine vibes are a problem but not sure. 

I keep reading about the lean sensor but that is just a kill switch if the bike goes over.  I just don't know what else to look at here....  Maybe the ignition coil but these are supposed to have some type of feedback to the ECU for that?? 

Ideas guys?  I am stumped.  Brand new air filter, exhaust verified to be wide open, box stock minus air filter, Tested IAT, TPS, MAP, CTS.  There is also talk of a speed sensor but I cannot see how that is directly related to the FI system or would cause this. 

[Peelz]

fuel pressure ok?

Maybe timing problem? or parking brake or clutch sensor causing it to limit revs? (660 thinking here)

was anything done to the motor?

[fastline]

Engine has never been touched.  I did verify that the timing marks are slightly off.  Usually not much of an issue but with FI, I guess it could be. 

I do know this is not a CDI induced rev limit.  Runs like crap, change plug, runs like a top for a few minutes.  With a carb, the carb does not flow fuel without air flow.  With FI, it does not care so I am sort of suspecting the timing issue but just not sure yet.  Surprised no one else has seen this. 

[Peelz]

Oh we've all seen it, but normally with aftermarket parts. Seen it be a bad stator, coil, or rectifier...no chance you have another 700 to swap parts?

Like I said... Rare to have trouble with stock machine...

[Kamakazi]

if i were a betting man, i would say poor oiling has wrecked your piston and cylinder.  electrical parts have a tendancy of either working or not working.  and the blue smoke indicates to me that the rings are not in good shape, and the fouled plug means alot of oil is being thrown onto the plug.  Being as you have to tear down the top end to check this, i take no responsibility in being wrong lol.   good luck

[Kamakazi]

a few more points to make are that the timing marks are a bit off, this also points a finger at a bad cylinder/piston as the chain would stretch from the piston and cylinder in rough shape.  if it was just a wet plug i could see just the timing being off, but since it is covered in oil, it has to be getting sprayed with oil somehow, and oil is not suppose to be in that part of the engine.  also the fact that you can start the engine and run it, kind of tells me it has nothing to do with fueling.  All finger so far from what you posted point at the cylinder/piston.

[fastline]

Well, I got another interesting fact a bit ago.  I requested the original air filter and lid be dropped off.  The OEM air filter is JUNK and if it was indeed used, it would have bypasses and was run in the sand.  Bad air filter, smoking, fouling plugs.....  I think we are going in....

Anymore thoughts, happy to listen.  I am really trying to figure out if I can get an acceptable leak down test completed on this engine.  That should help be pinpoint this a bit. 

[Peelz]

if i were a betting man, i would say poor oiling has wrecked your piston and cylinder.  electrical parts have a tendancy of either working or not working.  and the blue smoke indicates to me that the rings are not in good shape, and the fouled plug means alot of oil is being thrown onto the plug.  Being as you have to tear down the top end to check this, i take no responsibility in being wrong lol.   good luck

I was thinking this worst case scenario.  But was trying not to ruin the guys day

Way to be negative! LOL

[Kamakazi]

if i were a betting man, i would say poor oiling has wrecked your piston and cylinder.  electrical parts have a tendancy of either working or not working.  and the blue smoke indicates to me that the rings are not in good shape, and the fouled plug means alot of oil is being thrown onto the plug.  Being as you have to tear down the top end to check this, i take no responsibility in being wrong lol.   good luck

I was thinking this worst case scenario.  But was trying not to ruin the guys day

Way to be negative! LOL

why have him spend tons of hours troubleshooting electrical and getting pissed off at the machine when all he has to do is bite the bullet and remove the head or do a leakdown test  (i for some reason didnt think of doing a compression/leakdown test, kudos)

[Peelz]

Yeah Kama. Just tryin to think of everything else first.

[Adam]

sounds like a timing issue and/or bad rings.

what plug are you using? 

there are ZERO mods done? no slip on or a hotcam? anything?

proper amount of oil in it?

fresh fuel?

[fastline]

Comp test and valve clearance were the first things that were tested.  Obviously comp is on the comp release so not a real good estimate of engine condition.  Leak down should tell more.  However, I am not sure I have seen one lose plugs like this over a little oil and I am still kind of baffled on the richness issue. 

I fail to understand how valve timing would cause it to smoke though unless over heating the valves and burning the seals.  In which case adjusting the valve timing or changing the cam chain would not fix that.  I read where someone "fixed" their smoking problem with a valve adjustment....

[Peelz]

+1 adam "proper amount of oil" i was thinking that this morning....

Hope I dont sound "uppity" but its not overfilled is it? maybe a clogged oil line?

reason I ask, I had this SAME problem on my dad's cub cadet

I put like 4 quarts in a 2 quart lawnmower engine. blue smoked like mad, ate a plug.... yeah not same animal, but longshot....

(liquor and lawnmower maintenance don't always mix) 

these raptors, its always something REALLY simple, or a HUGE pain in the ass....

[fastline]

I keep hoping for simple but not looking likely.  I did check oil and actually not even showing on the dipstick.  I know it is slinging some oil but low oil, smoking, fouling plugs, etc.  Looking more and more like an engine issue.    I am just trying to think of any other tests I want to run before opening it.  I just don't have time today so not like I am going to stare at it for 5hrs instead of taking 1 to open it. 

[Peelz]

lol at stare for 5 hrs and 1 to open it.... thats me!


so no oil in the tank? hmmmm