diff --git a/io.c b/io.c
index c01296da..f948147e 100644
--- a/io.c
+++ b/io.c
@@ -364,8 +364,6 @@ static void writefd_unbuffered(int fd,char *buf,int len)
 		if (FD_ISSET(fd, &w_fds)) {
 			int ret, n = len-total;
 			
-			if (n > PIPE_BUF) n = PIPE_BUF;
-
 			ret = write(fd,buf+total,n?n:1);
 
 			if (ret == -1 && errno == EINTR) {
diff --git a/rsync.h b/rsync.h
index 2673c79f..471449e0 100644
--- a/rsync.h
+++ b/rsync.h
@@ -283,10 +283,6 @@ enum logcode {FNONE=0, FERROR=1, FINFO=2, FLOG=3};
 #define MAXPATHLEN 1024
 #endif
 
-#ifndef PIPE_BUF
-#define PIPE_BUF 512
-#endif
-
 #ifndef INADDR_NONE
 #define INADDR_NONE 0xffffffff
 #endif