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Discussion Starter · #1 ·
2012 ktm 500 exc 117 hours

Symptoms:
-Hard to start (40 F) requires many cycles to the point where the battery is drained
-Engine misfires
-Idle is all over the place
[email protected] constant RPM engine will pop from air filter intake area + misfire
-Bike dies constantly only after a few seconds of idling
-flameouts even with some throttle

Things done already:
(new)
fuel lines + inline screen
Fuel filter
Fuel pump
Fuel pressure regulator
KTM/Husky Fuel rail modification

-Fuel injector supersonic prof. cleaning
-JD FI tuner (stock open exhaust settings)
-bike @ stock .61v TPS setting
-Valves checked @ 100 hours (@117hrs now)

*I checked battery cables and from what I can see everything seems tight to the frame/battery

The next suggestion I've heard is to buy a new injector, after that I'm completely stumped. Should I double check valves again? I will post another video tomorrow. The misfiring seems more frequent with throttle.


Thanks anyone for lending a hand with suggestions!
 

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Basics first

You need to start at the beginning always. Compression and leakdown test first. Recheck valves. Erratic idle sputter and backfire can all be valve related issue. As can broken valve spring/valvetrain. Visual inspection of valvetrain may help here. Check back as needed. Good luck
 
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I agree with AugieDoggie. Basics first. I do realize you mentioned you checked the valves, but that is what it sounds like to me, you have a tight valve. It's easy to check. But go back to the basics before you start replacing parts.
 

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Discussion Starter · #5 ·
Thanks guys, I will start with leakdown/compression. My feeler guages did not fit into the rocker arms, I had to use the bent guages from my dr650. I ordered a new set just to cross my T's.
 

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2008 RC8 / 2007 690
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1 77241001000 THROTTLE BODY
1
335.54 €
2 81241085044 MAP SENSOR CPL. 09
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147.11 €
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83.69 €
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149.02 €
5 81241077044 TPS KPL. 09
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96.71 €
6 81241056044 THROTTLE COVER CPL. 09
1
41.54 €
7 81241060000 STARTER VALVE COMP.
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69.15 €
11 81241056020 SPECIAL SCREW AH
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5.46 €
12 61041077010 O-RING THROTTLE POS. SENSOR
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4.85 €
13 81241077030 SPECIAL SCREW
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2.67 €
14 75041085010 O-RING
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4.30 €
15 81241085020 PLATE 09
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17.19 €
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2.32 €
17 75041023020 O-RING 7,2x2,2
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5.59 €
18 75041023010 SEAL RING
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8.18 €
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3.96 €
20 81241031100 ELECTRONIC CONTROL UNIT
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369.78 €
21 77241031050 RUBBER BRACKET ECU
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40.92 €
22 61041080000 AMBIENT-AIR TEMPERATURE SENSOR
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15.49 €
23 0025050166 HH COLLAR SCREW M5X16 TX30
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1.57 €
24 61041088000 ROLLOVER SENSOR 05
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44.00 €
25 0025060206 HH COLLAR SCREW M6X20 TX30
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1.57 €
26 78141013190 FUEL FILTER
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4.64 €
27 77111014050 PROTECTION CAP TPS
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5.73 €
28 77507017000 CLAMP ABA 14MM
1
2.39 €
 

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Full Throttle
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1
7813000210015
7813000220015
* % IGNITION COVER
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79.38 €
4 78130040000 GASKET - IGNITION COVER
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11.40 €
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74.96 €
9 78039090000
78039090100
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37.92 €
10 75039093000 SPARK PLUG M12X1,25 LKAR8AI-9
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28.64 €
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1.57 €
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1.44 €
13 0019040106S FLAT HEAD SCREW ISA25 M4X10
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1.77 €
14 81230002010 RETAINING PLATE
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4.85 €
16 58439006000 IGNITIONCOIL IG3826 KOKUSAN'96
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54.36 €
20 78039205000 ROTOR EXC 08
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278.33 €
21 83039004000 STATOR
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133.06 €
22 0137120000 SPRING WASHER DIN0137-B12
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0.82 €
23 49030021000 COLLAR NUT M12X1 R/S
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4.30 €
25 0888030050 WOODRUFF KEY DIN6888-3X5X13
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35 0025050306 HH COLLAR SCREW M5X30 TX30
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1.57 €
50 0025060256 HH COLLAR SCREW M6X25 TX30
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1.57 €
 

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I had the same issue it was a pain to figure out. all happen after a had crash
1st issue was the fuel pump filer had a micro crack that you cant see (replaced) my fuel pressure was about 43psi and just took it out and tested in a bucked once replaced fuel pressure came back to 52psi
2nd issue was a hair line fracture in the spark plug (replaced) this is what cause it to run like crap for a few seconds and die

 

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2015 SDR, 2010 250xc-f, 2007 wr450f, 2016 Can am Renegade 1000 xmr, 2001 WS6, 2006 ZO6, 2006 GTO
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Sir,
Did it gradually start misbehaving or all at once? Some of the symptoms sound like low compression while others sound like fuel or timing. Is your timing chain tensioner stock? Put on your list to verify the tensioner and cam gear timing marks. I witnessed a slight backfire during starting a friends 450 jump the timing 2 teeth on exhaust cam.
 
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