Need a part number - Please Help!

[RLGfx]

Hi All,

I'm looking for help sourcing at least a part number for my MR4-BC slipper conversion.

Can anyone advise the part number for the replacement spur gear for this option part? can't find it anywhere on the web it basically looks like a B4 spur, but has a larger hole in the centre. (NO! I can't just drill out a B4 spur, would be off centre with my drilling skills...)

Thanks in advance

Robin