Differences

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--- tecnica:motori:honda_ntv650_carburetor [2025/12/22 16:53] – [Fuel and breather pipes placement] niccolo
+++ tecnica:motori:honda_ntv650_carburetor [2026/04/08 22:34] (current) – [Problem with the Keyster valve seat] niccolo
@@ Line 53: / Line 53: @@
 {{.:honda_ntv650:ntv650-revere-carburetor-d.jpg?200|}}
-The above is how I found the tubes in my **1988 NTV650J** Revere, but I have also a **1989 NTV650K** that has the breather tube going to the left side, in a mirror-like way:
+The above is how I found the tubes in my **1988 NTV650J** Revere, but I have also a **1989 NTV650K** that has the breather tube going to the left side, in a mirror-like way. In this case the binder bracket on the right top cover can accommodate the choke cable.
 {{.:honda_ntv650:ntv650-revere-carburetor-front-top.jpg?200|}}
 {{.:honda_ntv650:ntv650-revere-carburetor-rear-top.jpg?200|}}
-In this case the binder bracket on the right top cover can accommodate the choke cable.
 ===== Carburetors synchronization =====
@@ Line 101: / Line 100: @@
 It seems that also the Keyster kit **K-976EK** is compatibile with the NTV650 Revere, it contains fewer parts, but it contains the same rubber parts as the **KH-1348** kit, plus the oval O-ring of the air cut-off valve. Another kit from Keyster is the **K139** (also labeled **NTMOR-007G**), which includes only the float chamber gasket.
+===== Problem with the Keyster valve seat =====
+After overhauling the carburetors with the Keyster kit, I had **a problem with the float valve seat**. Even though I had adjusted the float level according to the manual (9.2 mm), after driving for a few kilometers, the fuel began dripping from the carburetor vent tube. Evidently the valve wasn't closing, and **the float chamber was overfilling**.
+To confirm that the fuel level was the problem, I connected two clear rubber hoses to the carburetor drains. The hoses were then bent upward, above the fuel cap. By loosening the **drain screws** of the carburetors, you can see the fuel level in the hose, which will be equal to the level in the float chamber. After a few kilometers of driving, I confirmed that the level in one of the two carburetors had risen several centimeters and was now reaching the breather pipe.
+{{.:honda_ntv650:keihin-carburetor-inspecting-fuel-level-in-float-chamber.jpg?direct&400|Inspecting the fuel level in float chamber}}
+When I removed the carburetor, I noticed that **the Keyster replacement had different dimensions than the original**, both the valve seat and the washer. To be safe, I reassembled the originals, and the problem was solved.
+{{.:honda_ntv650:keihin-carburetor-valve-seat.jpg?direct&400|}}
+{{.:honda_ntv650:keihin-valve-seat-honda-original.jpg?direct&280|}}
+{{.:honda_ntv650:keihin-valve-seat-keyster-replacement.jpg?direct&280|}}
+{{.:honda_ntv650:keihin-valve-seat-washer-honda-original.jpg?direct&280|}}
+{{.:honda_ntv650:keihin-valve-seat-washer-keyster-replacement.jpg?direct&280|}}
+===== Do not use red paste gasket sealant! =====
+I once installed a float chamber gasket whose size I didn't trust, so I added some **red gasket sealant**, by **Würth**. The result was disastrous: after less than a year and about 2000 km, the red paste dissolved in the fuel and formed a sludge in the carburetor float chamber. Naturally, the bike began to have idle problems and backfiring. Cleaning the inside of the carburetor was a pain, luckily **nitro thinner** seems to dissolve this red sludge.
+{{.:honda_ntv650:carburetor-red-paste-gasket-a.jpg?200|}}
+{{.:honda_ntv650:carburetor-red-paste-gasket-b.jpg?200|}}