Hi All, I’m hoping that someone may be able to help with the following please.
I have a 1981 chain drive 981cc TR1 and I’m currently rebuilding the engine. I’ve been advised that the left con rod (part no.5A8-Y1166-00) is heat damaged and in need of replacing.  I managed to source part no. 5A8-11660-00 which appears to be a later replacement.  It’s my understanding that this part was subsequently replaced by 5A8-11650-00, which I was unable to find.  It appears that the later bikes run with two 5A8-11650-00 con rods instead of one 5A8-11650-00 and one 5A8-11660-00 or one 5A8-Y1165-00 and one 5A8-Y1166-00…  If that makes sense.
The problem is that part no.5A8-Y1166-00 has two oil holes and 5A8-11660-00 has only one.  Obviously I’ll need a different bearing but my question is whether there’s a potential issue running with only one oil hole.  Are the two holes necessary?  

Evening Ali, thanks for the reply.  I’ve done a little more research and it appears that it’s part no.5A8-11650-00 that has two holes and not 5A8-11660-00 which only has one.  Curiously the older part no.5A8-Y1165-00 has one hole whilst 5A8-Y1166-00 has two, which is totally illogical, but I should have known better.  I ordered a second hand 11650 from America shortly after posting my question, which should hopefully resolve the issue.  To be honest I was never happy with the idea of using only one hole to cool the rear cylinder, but thought I’d ask the question in the vain hope of avoiding the inevitable.