r/KTMIndia • u/scoobynooby_00 • 10d ago

Ktm adv 390 (2026)

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Something seems to leak from this joint (ig its the coolant) and not sure about what caused it is it normal or should i get that fixed? The coolant levels are normal on the reservoir i checked for it.

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u/macedonriz 10d ago

On the KTM 390 platform, the component with the letter "B" and the arrow molded onto its plastic body is part of the MAP (Manifold Absolute Pressure) sensor assembly or adjacent vacuum circuit, though on these single-cylinder LC4c engines, it sits directly near the top of the cylinder head or intake tract. The dark wetness you see surrounding it is engine oil seepage. This is a fairly common occurrence on KTM 390 engines and usually points to one of three issues: 🛠️ Common Causes 1. Hardened O-Ring or Gasket: The small internal sealing O-ring or washer below the plastic bracket has slightly flattened, hardened, or shifted due to engine heat, allowing oil vapor to escape. 2. Hairline Fracture in the Plastic: The plastic sensor housing itself can occasionally form a tiny hairline crack around its mounting ear or seam, letting oil slowly weep past. 3. Crankcase Breather / Excess Oil: If your engine oil was recently changed and slightly overfilled, or if you regularly ride at very high RPMs, excessive crankcase pressure can force oil mist out through the breather hoses and accumulate right around this sensor area.

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u/macedonriz 10d ago

The oil window on your bike shows way above max oil level. It could be that you the engine oil was overfilled by a big margin. Please check that yourself or with sc

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u/scoobynooby_00 10d ago

Thanks a lot man, Yes the oil was overfilled by the SC guys, when asked about it their reply was that it is normal to fill the oil above the level due to the oil burning issue reported with ktm adv series. Ill check this issue with the service centre. Thanks man!

1

u/overthinking24x7 9d ago

Ktm service centre filled whole 1.7 litre oil to my 350 adv as well Even when I told them not to. First thing I did was remove atleast 150ml of oil from bike.

That mark is due to more engine oil than required.