diff --git a/cmake/test.cmake b/cmake/test.cmake
index 5922c5106..9a42ac263 100644
--- a/cmake/test.cmake
+++ b/cmake/test.cmake
@@ -178,8 +178,10 @@ function(_json_test_add_test test_name file main cxx_standard)
             COMMAND ${memcheck_command} $<TARGET_FILE:${test_target}> ${DOCTEST_TEST_FILTER}
             WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
         )
+        # under Valgrind the slowest tests take close to 25 minutes, so ctest's
+        # default timeout of 1500 seconds leaves no headroom
         set_tests_properties(${test_target}_valgrind PROPERTIES
-            LABELS "valgrind" FIXTURES_REQUIRED TEST_DATA
+            LABELS "valgrind" FIXTURES_REQUIRED TEST_DATA TIMEOUT 3600
         )
     endif()
 endfunction()
diff --git a/include/nlohmann/detail/output/binary_writer.hpp b/include/nlohmann/detail/output/binary_writer.hpp
index 0c3c823ac..c9bdc696f 100644
--- a/include/nlohmann/detail/output/binary_writer.hpp
+++ b/include/nlohmann/detail/output/binary_writer.hpp
@@ -2422,7 +2422,6 @@ class binary_writer
             nothing large has been written then, and the caller writes the
             document in two passes, which reports that error
     */
-    template<typename SinkType = OutputSinkType, typename std::enable_if<is_detected<sink_written_t, SinkType>::value, int>::type = 0>
     bool write_bson_document_single_pass(const BasicJsonType& document)
     {
         const std::size_t start = oa.written();
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 693320ed5..2a7289203 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -30394,7 +30394,6 @@ class binary_writer
             nothing large has been written then, and the caller writes the
             document in two passes, which reports that error
     */
-    template<typename SinkType = OutputSinkType, typename std::enable_if<is_detected<sink_written_t, SinkType>::value, int>::type = 0>
     bool write_bson_document_single_pass(const BasicJsonType& document)
     {
         const std::size_t start = oa.written();