KTM 950 Adventure Carburetors

Been quite busy lately with several different things both motorcycle related and personal.

Looked over the carbs on the KTM 950 Adventure.

Had decided to change some of the O-rings and the vacuum slides since there was a leak when brining it out of hibernation last spring, so ordered some parts and sadly parts arrived damaged:


But the place I ordered from are sending a new gasket kit (very expensive so wont accept damaged parts), but to not have to wait for parts Im reusing the damage membrane holders.

When starting the bike before draining the oil it was not running good at all so guessed something was blocked, first time I had the carbs all the way off the bike:

KTM 950 carbs LC8 engine

Used two trays to keep the parts separated.

Found some sticky goo under the diaphragm cover of the front carb and wonder if it comes from the crankcase ventilation, plan to just reroute that into a separate bottle and see how much if any that seems to come out of it.

KTM 950 carbs LC8 engine

Seems like one of the vacuum pistons was in a smaller plastic bag so it had a small kink from being a little compressed in storage but they both feel nice and soft so should work just fine:

Hmm one ing a big bag?

And on the rear carb there was quite a bit of carbon deposits for some reason, know I had some serious backfiring a long time ago when the choke cable had not been fully seated and held that wide open all the time resulting in backfiring with flames up the intake:

Membrane sooth

Looked over all the jets and the one seen loose in this picture was blocked:

Blocked jet

Used a plastic bristle from a dish brush to clean them:

Bristle from brush to clean

These smaller membranes also came with the kit so replaced them:

Replacing small membranes

And when changing the vacuum pistons make sure to get the lower washer on the needle out, both mine were stuck and needed some help with a dentist torture tool to come out:

Needle with the stuck lower washer

Also adjusted the float bowls but forgot to take any pictures, went with 3mm above carb surface.

Lubed the cables, helpful tool:

Lubing wires

Buttoned everything back up so the bike could be started without the airbox since I had unbolted the TPS (throttle positioning sensor) rather then undo the electrical contact so it needed to be adjusted.

Started up the bike, adjusted the idle and sync the carbs before adjusting the sensor, was a bit off at 0,726 V and should be as close to but below 0.6 at idle, once adjusted:

Adjusting TPS (throttle positioning sensor)

Undoing the bolt it can be adjusted:

Adjusting TPS (throttle positioning sensor)

So its a little closer to being ready, have started seeing some motorcycles out now the big paved roads are OK in the afternoons the cold nights freezes any water on the roads and makes for some really slippery ice patches and there is still plenty of snow in the forests.

4 comments to KTM 950 Adventure Carburetors

  • peter

    hello my ktm 950 lc8 supermoto 2005 seems to back fir from the back cilinder on idlie dosent do it when the choke is on do you have any ideas wot mite be wrong?


    • Johan

      Hi Peter.

      Have you touched the choke cables? Had trouble with mine a while back with it not running well after having the carbs out and turned out one of the choke cables were not seated properly down by the carbs.

      Intake leaks with not properly seated carbs or torn/damaged carbs boots can cause strange backfiring also.


  • peter

    hi johan i i have only owned the bike about a year and have always had a backfireing problem since i got the bike so i dont realy no the bike history it has only got 14000 miles on the clock so its not gone round the world and back . it seems to run fine apart from the backfiring but since this is the only one i have drove i have nothing to compare it with .
    thanks for your help i will give the carbs a looking at and the coke cable


    • Only time I have had bad backfiring was when one of the hoses to I use for syncing the carbs a plug on one of them came undone and then it was really loud exhaust bang when engine braking and revs went below 4000, other then that it ran fine.

      I have removed all the emission stuff on my bike a long time ago, did a video a while back showing my setup for syncing the carbs, might be worth checking at least if digging into the bike and opening up the air box:

      If it idles fine and pulls well I would start searching for any small leaks, it can be quite tricky getting the carb boots seated properly, many have had trouble and even after an authorized service there have been issues with it being damaged or not seated properly.

      Hope you get it sorted out.


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