Top End Rebuild 1st Oil Change

Status
Not open for further replies.
Ricochetrider

Ricochetrider

Joined
Feb 10, 2015
Messages
41
Country flag
Hi guys, sorry if this has been beat to death, but searching didn't seem to turn up anything on this, SO... that being said:
1974 850 Commando:

I'm ready for an oil change after a top end rebuild. I have the oil & filters, but there seems to be some differing opinion (between me & my buddy who has volunteered to help me) about whether or not to drain the sump. I figure, "why not?" drain the sump. He says IF we drain the sump, it must be SUPER clean before refilling, something could plug or block the oil return line, he NEVER drains his sumps, and on and on with all manner of doomsday shyte, dire warnings, furrowed brows, etc, on the subject...

He also advises me to find out how much oil to put back in the sump IF we do *gasp* drain the sump.


ALSO,
Seems some folks have buggered their sump drain plugs quite dramatically over the ages...
I saw a link in my searching, to a sump drain plug that had a screen filter and a smaller drain plug built in, think it was on Old Britts web pages... What's the collective wisdom on this plug/drain thing?

Apologies & thanks in advance.
 
Well, I confused myself on a different thread but now I'm REALLY confused! The oil drain plug is at the bottom of the engine. I don't see how you can drain the oil/perform an oil change without automatically draining the sump...which is the bottom of the engine. Or am I just confused again? ;)
 
It's the Triumph engine where the sump plug is best left alone as the tiniest spec of dirt disturbed has the potential to stick under the ball in the plunger pump and stop the oil returning, not a Norton gear pump issue. You have the large sump plug with its screen that needs cleaning and a sump plug with a magnet that will be full of ring/bore material.
 
I always drain the sump on all my bikes and I never "refill" it. These are dry sump machines and there is very little oil in the sump normally. The Norton riders manual says to drain the sump and to expect it to take a couple of seconds for oil to return when you start the bike.

With 40+ year old aluminum cases, you should be very careful of anything that screws into them. If it won't go in with fingers, then tools will make a mess - in other words, screw the plug in finger tight before tightening with tools and it needs to be tight, not super tight.
 
Last edited:
Ricochetrider said:
I'm ready for an oil change after a top end rebuild. I have the oil & filters, but there seems to be some differing opinion (between me & my buddy who has volunteered to help me) about whether or not to drain the sump.....
He also advises me to find out how much oil to put back in the sump IF we do *gasp* drain the sump.
Click to expand...

Suggest you seek advice from someone who knows something about Nortons.
 
Ricochetrider said:
I saw a link in my searching, to a sump drain plug that had a screen filter and a smaller drain plug built in, think it was on Old Britts web pages... What's the collective wisdom on this plug/drain thing?
Click to expand...

As it's an 850, it should have a sump strainer [39-42] and a separate drain plug [31].
https://andover-norton.co.uk/en/sho...e-crankcases-filter-breather-tachometer-drive

Therefore, you can drain the sump without disturbing the strainer.
If the strainer is removed then it should be thoroughly cleaned but as kommando said this is more important on Triumph twins with "ball-valve" plunger pumps.
 
Ricochetrider said:
Hi guys, sorry if this has been beat to death, but searching didn't seem to turn up anything on this, SO... that being said:
1974 850 Commando:

I'm ready for an oil change after a top end rebuild. I have the oil & filters, but there seems to be some differing opinion (between me & my buddy who has volunteered to help me) about whether or not to drain the sump. I figure, "why not?" drain the sump. He says IF we drain the sump, it must be SUPER clean before refilling, something could plug or block the oil return line, he NEVER drains his sumps, and on and on with all manner of doomsday shyte, dire warnings, furrowed brows, etc, on the subject...

He also advises me to find out how much oil to put back in the sump IF we do *gasp* drain the sump.


ALSO,
Seems some folks have buggered their sump drain plugs quite dramatically over the ages...
I saw a link in my searching, to a sump drain plug that had a screen filter and a smaller drain plug built in, think it was on Old Britts web pages... What's the collective wisdom on this plug/drain thing?

Apologies & thanks in advance.
Click to expand...

Tom, whoever gave that advice must stay away from the wrenches on your Norton.
 
What a fool to surgess not to drain the sump, if you don't do it you be mixing old oil with nice clean oil, if I was you I keep your mate far away from your maintenance work, you should have no problems with your drain plug, just make sure it screws in straight and don't force it, make sure the treads are clean before fitting it.

Ashley
 
Not a bad idea to get a Comstock sump plug flapper valve you know.
Id drain anything I could, change the filter and probably wash out the
oil tank too.
 
Guys, thanks for the comments and advice. I do have an aftermarket manual and I know I can download the original Norton 850 Commando manual on line, so I'll get it sorted.
And yeah... my buddy rides Triumphs, so guess that's the source of his worries!
 
Factory book is the baseline for information. Remember too that most of the original workshop tools are once again available.
 
Status
Not open for further replies.

Similar threads

A
  • Locked
MkIII Top End Rebuild Pics and Sanity Check
Replies
17
Views
1,665
fiatfan
fiatfan
freefly103
  • Locked
70 Commando top end rebuild complete
Replies
6
Views
1,244
freefly103
freefly103
iceteanolemon
  • Locked
first big ride after top end rebuild 71 norton
Replies
4
Views
1,180
concours
concours
M
Wet Sump During Top End Rebuild /Cylender Hone Question
Replies
3
Views
1,321
norbsa48503
N
R
  • Locked
top end rebuild.
Replies
3
Views
1,059
pommie john
pommie john
Back
Top