A problem with the change of MTU on the site tunnelbroker.net

[cashipvsix]

Hi people!
In the settings of Tunnel Details -> Adnanced -> MTU - I try to change the MTU
After that on my router I raise the Ipv6 tunnel Internet interface.
But the value of MTU is not what I asked it on the site.
But when you lift the interface, the MTU value is always the same.
What could be the problem?

My inernet interface:

ppp6      Link encap:Protocol PPP (Point-to-Point Protocol) 
          inet addr:xx.xx.xx.xx  P-t-P:xx.xx.xx.xx  Mask:255.255.255.255
          UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1492  Metric:1
          RX packets:31 errors:0 dropped:0 overruns:0 frame:0
          TX packets:42 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:3
          RX bytes:3235 (3.2 KB)  TX bytes:13396 (13.3 KB)

he-XXXX Link encap:IPv6-in-IPv4 
          inet6 addr: 2001:470:XX:XXX::X/64 Scope:Общий
          inet6 addr: fe80::XXXX:XXXX/64 Scope:Link
          UP POINTOPOINT RUNNING NOARP  MTU:1472  Metric:1
          RX packets:2 errors:0 dropped:0 overruns:0 frame:0
          TX packets:4 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1
          RX bytes:192 (192.0 B)  TX bytes:384 (384.0 B)


ping -M do -s 1472 216.66.80.90
PING 216.66.80.90 (216.66.80.90) 1472(1500) bytes of data.
ping: local error: Message too long, mtu=1492

ping -M do -s 1464 216.66.80.90
PING 216.66.80.90 (216.66.80.90) 1464(1492) bytes of data.
1472 bytes from 216.66.80.90: icmp_seq=1 ttl=55 time=64.6 ms

[broquea]

Setting the MTU on our interface changes the MTU on OUR side. You still need to manually adjust the MTU on YOUR side.

[cashipvsix]

Setting the MTU on our interface changes the MTU on OUR side. You still need to manually adjust the MTU on YOUR side.

Thanks! MTU has changed!
But the problem remained.
I will not create a new branch, but I'll ask the question here the traffic goes to - Server IPv6 Address: 2001: 470: 27: 805 :: 1/64

he-XXXXXX Link encap:IPv6-in-IPv4 
          inet6 addr: 2001:470:27:805::2/64 Scope:Общий
          inet6 addr: fe80::XXXX:XXXX/64 Scope:Link
          UP POINTOPOINT RUNNING NOARP  MTU:1460  Metric:1
          RX packets:73 errors:0 dropped:0 overruns:0 frame:0
          TX packets:194 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1
          RX bytes:5736 (5.7 KB)  TX bytes:58627 (58.6 KB)


$ traceroute6 he.net
traceroute to he.net (2001:470:0:76::2) from 2001:470:27:805::2, 30 hops max, 24 byte packets
1  cashipvsix-2.tunnel.tserv24.sto1.ipv6.he.net (2001:470:27:805::1)  62.205 ms
* *

$ wget -6 -O / dev / null http://he.net
-2017-07-27 01: 37: 49-- http://he.net/
Recognized as he.net (he.net) ... 2001: 470: 0: 76 :: 2
Connection to he.net (he.net) | 2001: 470: 0: 76 :: 2 |: 80 ... the connection is established.
HTTP request sent. Waiting for an answer ... ^ C

I do not even know what to do ...
Could you suggest more options where there can be a mistake?