Author Topic: Which Oil  (Read 1066 times)

Offline Chrisf1

  • A's Best Friend
  • ***
  • Join Date: Jun 2008
  • Posts: 96
  • Karma: 0
Which Oil
« on: 03.03. 2009 18:01 »
Hi again everyone I have now completed 250 miles since total rebuild and about to do adjustments, tappets etc and I am also going to fit a filter on the return side. What I gather from previous threads having an in line oil filter makes the sludge trap obsolete if used with modern oils that keep particles suspended for the filter to trap. I have up till now been using straight 40 grade. Dare I ask what is the best oil to use now with the filter fitted? The bike unfortunately still wet sumps in 4-6 weeks so I suppose using a modern multigrade will worsen that but I will have to live with it many thanks Chris

Offline Triton Thrasher

  • Scotland
  • Wise & Enlightened
  • *
  • Join Date: Feb 2009
  • Posts: 1588
  • Karma: 20
Re: Which Oil
« Reply #1 on: 04.03. 2009 09:23 »
The sludge trap may still eventually fill up with carbon black from the oil, as paper filters don't remove it.  That's my theory anyway.

Online BSA_54A10

  • Wise & Enlightened
  • *
  • Join Date: May 2008
  • Posts: 2079
  • Karma: 32
    • BSA National
Re: Which Oil
« Reply #2 on: 04.03. 2009 13:53 »
As for oils & filters.
The sludge trap is actually a full flow , zero pressure loss. centrifical oil
filter and is one of the oldest and best filtering mechanisms know to
Its job is to specifically protect the big ends from particulates which it dose
exteramly well and as such should be left in circuit regardless of what other
filter you have added to the system.
BSA in their wisdom fitted 4 filters to the oil system to do 4 different jobs.
One in the oil tank to protect the high pressure side of the oil pump.
If it goes through the mesh then it will safely pass through the pump.
One in the crank to protect the big ends.
One in the sump to protect the return side of the oil pump.
And finally there is the oil tank itself which was designed to allow
particulates to settle out in the bottom. below the outlet.
So when you read the crap that many "experts" come out with implying that the
screen in the sump is the only filter in the system, then it shows that the
author knows absolutely nothing about the motorcycle in question and has zero
understanding of the principles of the engineering that he is writing about.

Now if you follow the recommended maintenance schedules that system will
virtually guarantee you at least 20,000 miles from your bottom end regardless of
how you ride the bike and was considered adequate when the bikes were new.

Old oils had addatives (or lack there of) in them to facilitate contaminates
joining together into big globs to aid then settleing out or being spun out..
Modern oils have addatives in them to prevent contaminates joining together into
big globs and hold the fine particles in suspension to aid removal by the paper
filter element.

The paper element filter has a finer "mesh size" than the screen in your oil
tank so as it now makes that ( and the sludging ) redundant you would be well
advised to use an oil designed to be used with paper filters, a modern
Unfotruneatly this filter will not remove acids or water so you will still need
to change your oil and as we tend not to ride as much as the bikes were designed
to then you should be changing your oils by the calendar and not the odometer,
and such oil changes could be considered a minimum . YOU CAN NEVER CHANGE THE

Bike Beesa

Offline Chrisf1

  • A's Best Friend
  • ***
  • Join Date: Jun 2008
  • Posts: 96
  • Karma: 0
Re: Which Oil
« Reply #3 on: 07.03. 2009 17:01 »
Thanks for the replies I know very little about oils apart from the importance of its presence. Are all or most modern multigrades detergent oils? if not have you a suggestion for a detergent multigrade best suited for my bike bearing in mind it wet sumps 4-6 weeks. Thanks Chris