BSA Owners' Club Workshop Discussions

The BSA Workshop => Singles => Topic started by: rustyboots on 23 Feb, 2025, 11:53

Title: B31 engine oil level questions
Post by: rustyboots on 23 Feb, 2025, 11:53
Hi all

Q1. does the B31 wet sump after periods on non use

Q2. does the oil level need to be checked hot or cold, the bike is not on the road at the moment so can only run it stationary.

Q3. With the bike on the main stand, the oil level when cold is around 2 inches below the level line on the tank, do i need to add oil to run it safely.

Q4. As the bike is new to me, should i just drain it down and fill with fresh oil.

TIA
Mark
Title: Re: B31 engine oil level questions
Post by: idie on 23 Feb, 2025, 16:35
Yes they do wet sump after standing.So long as the oil is below the outlet in oil tank. About an inch from the top is good.
Title: Re: B31 engine oil level questions
Post by: Rog1 on 24 Feb, 2025, 09:17
Q4:
Yes, you should change the oil; this is good practise when buying any used vehicle, at least for private sales. After an oil change, I start the bike and watch for oil returning to the tank. Once it starts returning I put my finger over the hole for 20 seconds or so. I like to do this because the rocker box is fed from the return pipe and I want to make sure oil is getting up there.

See if you can get a good look at the bottom of the oil tank once it's drained, as muck and debris tends to gather there. If in doubt, remove the tank and give it a clean out.
Title: Re: B31 engine oil level questions
Post by: rustyboots on 24 Feb, 2025, 12:35
Thanks very much guys