The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: atener on 31.12. 2008 20:56

Title: oil return?
Post by: atener on 31.12. 2008 20:56
Hi there just got my  A10 up and running, started fairly easily (third kick) .After checking the return flow to the oil tank after a few seconds the flow was good and strong at tickover. But on revving it slightly
the flow started to be a bit irregular (not a constant flow). Is this correct or am i just panicking over this?
Title: Re: oil return?
Post by: trevinoz on 31.12. 2008 20:58
That is normal as the scavenge pump is larger than the feed pump, therefore it will pump oil out quicker than it can be supplied.
Title: Re: oil return?
Post by: atener on 31.12. 2008 21:02
Thanks trev thats put my mind at rest.
Title: Re: oil return?
Post by: a10gf on 31.12. 2008 21:06
Congrats on getting the bike going. As you describe it, your oil return is normal, as the pump has more return capacity than feed, the steady flow you see in the beginning is the amount of oil that has ended up in the sump when the engine was not running.

Search the forum, you'll find topics about it.


(edit, trev., you got there just before me!)
Title: Re: oil return?
Post by: Richard on 31.12. 2008 21:23
funnily enough this is the exact thing that I was concerned about when I first rebuilt my A10 engine and started it up for the first time, after I was given the exact same answer I reliased just how much I had forgotten over the years and how much is in ones head given a few timely reminders. Just where would we be without the web when one is having a senior moment and thank goodness for forum sites like this one
Title: Re: oil return?
Post by: A10Boy on 01.01. 2009 18:44
This month's [Jan 2009], edition of "The Classic Motorcycle" contains a great article about oil pumps. In fact the featured pump is from an A10. Like others have said that irregular flow is normal.