NGK BR8EIX. This was the recommended plug for 500cc RE in the NGK catalog as well.
Sat Sree Akaal:
Do you have a EFI UCE bike ? If so, there are a few points to consider - These bikes are originally fitted with Bosch WR7 DDC4 from the factory in Chennai. We cannot get them here in USA. The
closest equivalent to these are BPR 6ES or BPR 6EIX (iridium).
Some people might consider NGK of 7 heat range to be more appropriate. Others may think of switching to two plug system - colder (NGK 7) in summer and hotter (NGK 6) in winter.
Heat range of NGK runs opposite to that of Bosch - as the number increases the plug becomes COLDER in NGK and HOTTER in Bosch. It seems that NGK catalog has not been updated for these new bikes and still recommend the heat range 8 that was used for the older engines. The plug BR 8EIX will work but it is a COLD plug that may not fully burn the fuel and at some point start to deposit carbon. Secondly, this plug is not projected whereas original Indian plug is projected so there is a slight difference in the location of spark.
If you want, buy a BPR 6EIX plug and try in your bike - you will see the difference in how the pick up changes.
I also had a heat range 8 NGK plug in my bike long time ago. When these bikes were new and I had a starting problem with my G5, we had a very extensive discussion on finding right spark plug (
link below). Since then and after careful investigation and experimentation, it became clear that the heat range should be 6 for NGK to match Bosch OEM plug.
The link below has lot of useful input from people from around the world that is worth going through.
http://www.enfieldmotorcycles.com/forum/index.php/topic,6334.0/all.html