You can purchase Indicator flash rate relays from many accessory stores/ebay.
for example:
http://stores.ebay.com.au/RatedR-Custom ... idZ2QQtZkm
The plug & play units are suited to most 2-wire systems and are the most basic of installs.
1. Purchase the relay
2. Locate the relay position
3. Remove the OEM unit
4. Plug in the new!
picture example:
Relay is located under pillion seat.

this is the OEM relay you want to replace.

Plug the new relay into the factory connector (no splicing req) and mount it securely.

DONE! you're new LED indicators will now flash at normal rate.
Note: for 3-4 wire systems some splicing/resistors may be required.