diff --git a/interfaces/cython/cantera/reactor.pyx b/interfaces/cython/cantera/reactor.pyx
index 15080efa2..3dadcc9e2 100644
--- a/interfaces/cython/cantera/reactor.pyx
+++ b/interfaces/cython/cantera/reactor.pyx
@@ -12,7 +12,7 @@ cdef class ReactorBase:
         self.rbase = newReactor(stringify(self.reactor_type))
 
     # The signature of this function causes warnings for Sphinx documentation
-    def __init__(self, ThermoPhase contents=None, name=None, **kwargs):
+    def __init__(self, ThermoPhase contents=None, name=None):
         self._inlets = []
         self._outlets = []
         self._walls = []
diff --git a/interfaces/cython/cantera/test/test_reactor.py b/interfaces/cython/cantera/test/test_reactor.py
index c9d323685..05e17c69c 100644
--- a/interfaces/cython/cantera/test/test_reactor.py
+++ b/interfaces/cython/cantera/test/test_reactor.py
@@ -520,6 +520,11 @@ class TestReactor(utilities.CanteraTest):
             with self.assertRaises(AttributeError):
                 x.foobar
 
+    def test_bad_kwarg(self):
+        self.reactorClass(name='ok')
+        with self.assertRaises(TypeError):
+            r1 = self.reactorClass(foobar=3.14)
+
 
 class TestIdealGasReactor(TestReactor):
     reactorClass = ct.IdealGasReactor
@@ -1165,7 +1170,7 @@ class CombustorTestImplementation(object):
 
         # create the combustor, and fill it in initially with a diluent
         self.gas.TPX = 300.0, ct.one_atm, 'AR:1.0'
-        self.combustor = ct.IdealGasReactor(self.gas, volume=1.0)
+        self.combustor = ct.IdealGasReactor(self.gas)
 
         # create a reservoir for the exhaust
         self.exhaust = ct.Reservoir(self.gas)