Excessive Oil Consumption

[72kettle]

Hi, I have a 1976 Model A GT750 that has very high 2 stroke oil consumption and therefore it smokes more than it should too. It uses about 1 litre to 180 miles, 290 kilometres so I put a spare pump on I had but this made no difference. I've done a compression test and they are all at 120psi on each cylinder. The pump is adjusted to the correct marks on the actuator arm so I'm at a loss as to the cause of this. Any ideas or advice would be greatly appreciated. Something else I thought of, was there different gearing on the oil pump drive for different models? Many thanks, Ian

[barney01]

Lots of info here
https://www.pinkpossum.com/GT750/Oilpump.htm

[teazer]

Without looking at the bike and not knowing its history, it's hard to diagnose, but the place to start is probably the octopus/spider ie the oil distribution manifold. it is most likely that the check valves which are inside the banjo connections, are weeping.

Remove the oil pump and the octopus which is a bit of a pain to get to and gently flush the oil lines out. Do not use high pressure air because it will damage the balls and springs inside the banjos.

If the bike is not run very often, oil will seep down and partially fill the crankcases and it will smoke like someone from the sixties until it is run hard enough to burn off the excess oil.