Could someone tell me the thread size for the vent on the inner primary for an aluminum primary '67 FLH? I need to put a plug in it. Thanks in advance.

 

one by starter is 1/8 pipe others same top transmission and vent oil pump. If leaking use a push in 1/4 self locking and run a line up under seat that's way mine is no worries and high out of water splashing. Luck.

 

Thanks Hurricane. I thought it might be 1/8 pipe but the plug I had didn't want to start and I was afraid of cross threading the hole. It's a PITA to get to right next to the frame. PO converted to belt drive and left the vent hole open.

 

PO converted to belt drive and left the vent hole open ... That would be messy soon :>(

 

1/8 npt. If it feels like somebody cranked the old fitting down real tight you may need to take a tap and freshen up the threads a bit.

 

Thanks everyone. Thankfully Larry, the PO never got it to run. I drilled a small hole just into the end of the plug and was able to use a small easy out in the hole to get the plug started. Problem was to get the plug perfectly straight to start the threads. Pretty difficult with the frame in the way.