My first Norton! Oil lines routed wrong?

I can't get images to upload so I'll try to describe the way the oil lines are routed on my Norton.
Bike is a 1972 Commando 750. I have no history on the bike so I'm checking everything before I ride it.

I've only run it a couple times since I got it. It's very clean, I suspect it's been rebuilt and not ridden since rebuild.

I think the oil lines are routes wrong.

The hose from the oil tank screen fitting is connected to a spin-on oil filter. There's a hard pipe that comes down from the back of the oil tank with nothing on it. I think the hose currently on the screen fitting should be connected to the pipe.

The other hose from the oil filter goes to the left (inner) oil pump pipe. This appears to be the pump inlet. That hose should be connected to the right pump pipe.

I think whoever put the oil hoses on intended to filter the oil pressure side rather than the return flow.

The right (outer) oil pump pipe is connected to the tube on the top front of the oil tank. That hose should go to the screen fitting on the back of the tank.

I think the tube on the top of the oil tank is supposed to connect to the back of the air filter assembly.

Here's links to pictures.

Inside hose comes from oil filter.


Back of oil tank. Screen fitting and pipe with no connection at upper right.

The breather from the engine is connected correctly.

2WheelsUp, thanks for the link to the thread! I have the oil lines routed correctly now.

I had found the oil diagram and knew about the parts manual being wrong but the pictures help a lot.

I am used to the idea of filtering return oil rather than feed oil. I found a thread here that explained that the oil pump likes to push rather than suck oil.

The term "banjo" is better than oil tank screen fitting.

Yes, oil tank gauze screen output/banjo line runs to the oil pump...right-most pump hard pipe I think check diagram). The oil filter line runs to the tank hard line coming down the top of tank rear side corner (at least on the later type tanks mounting on right side...early type were across centerline of frame and have different fittings).

Also, pay attention to the two hoses coming off the oil filter...one takes the return line from the pump, the other goes to the tank as mentioned previously. There is a correct direction of flow through the filter and I cannot recall what is right at this time...so check it b/c most modern filters have a check valve inside for anti-drain-back properties....will not flow in wrong direction.

BTW, for posting/hosting pics directly here, you need to be a VIP member....but you can link to a photo hosting website to display images hosted elsewhere.

Tornado, thanks for mentioning the filter flow direction. I hadn't thought of that.

On my bike, the hose from the pump return pipe is on the right side of the filter adapter. This agrees with the oil diagram at the link above.

MLW9110 said:

Tornado, thanks for mentioning the filter flow direction. I hadn't thought of that.

On my bike, the hose from the pump return pipe is on the right side of the filter adapter. This agrees with the oil diagram at the link above.

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Look in the oil filter mount - it is marked in and out. Here is a picture: https://andover-norton.co.uk/en/sho...ad-to-suit-3-8-id-oil-hose-with-barbed-pipes-

It's better here to say timing side and drive side. "Right" is open to interpretation based on where you are looking from. I'm guessing that your hoses are backwards if you are looking from the rear of the bike. "In" is closest to the mounting holes and therefore closest to the timing side. "In" comes from the oil pump return. Please double-check me!

The oil filter mount is marked IN on the timing side connection. The OUT port is in the middle of the mount.

The hose from the return pipe (inner pipe) is connected to the IN port of the filter mount.

I'm confident that I have the oil hoses connected correctly now.

Should be able to run the engine tomorrow and verify oil coming out of the retunh to the tank.

I was an aircraft mechanic. Right and left was always from the perspective of sitting facing forward.

MLW9110 said:

The oil filter mount is marked IN on the timing side connection. The OUT port is in the middle of the mount.

The hose from the return pipe (inner pipe) is connected to the IN port of the filter mount.

I'm confident that I have the oil hoses connected correctly now.

Should be able to run the engine tomorrow and verify oil coming out of the retunh to the tank.

I was an aircraft mechanic. Right and left was always from the perspective of sitting facing forward.

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An aircraft mechanic will handle our bikes with ease I'm sure.

But in the last couple of years there has been at least one person on here who asked questions and got everyone very very confused with left right, clockwise anticlockwise and even maybe up down. No names mentioned but it involved magnetos.

So I definitely understand why Greg asked for clarity.

Have fun.

I understand, not everyone uses the same perspective. I was taught in formal training the conventions for right, left, outboard inboard etc.

I also was a medical equipment tech. Proximal and distal had to be added to my vocabulary.

This aircraft mechanic had a very difficult time getting the damn air cleaner back on! I finally removed the carbs to get the carb boots in. Still don't like the way they fit. Compressed too much. I appreciate the filter arrangement on my other vintage bikes more. Except for the 1977 Honda CB550F. The airbox on that is difficult because of the carb boots. The filter is easy to change though.

MLW9110 said:

I was an aircraft mechanic. Right and left was always from the perspective of sitting facing forward.

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Yes this is how I learned for working on cars. Several workshop manuals stated left/right is always from facing forwards.

MLW9110 said:

I understand, not everyone uses the same perspective. I was taught in formal training the conventions for right, left, outboard inboard etc.

I also was a medical equipment tech. Proximal and distal had to be added to my vocabulary.

This aircraft mechanic had a very difficult time getting the damn air cleaner back on! I finally removed the carbs to get the carb boots in. Still don't like the way they fit. Compressed too much. I appreciate the filter arrangement on my other vintage bikes more. Except for the 1977 Honda CB550F. The airbox on that is difficult because of the carb boots. The filter is easy to change though.

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Yes. The aircleaner can be an issue. Gets easier after 10 times.

The Brits also like to talk about nearside and offside.

From horse riding.

johnm said:

Yes. The aircleaner can be an issue. Gets easier after 10 times.

The Brits also like to talk about nearside and offside.

From horse riding.

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I don't think it's to do with horse riding
It simply means kerbside IE in England it's on your left because we drive on the left
But there are some parts of the world that drive on the right I believe?
Therefore their kerbside would be to ones right

MLW9110 said:

This aircraft mechanic had a very difficult time getting the damn air cleaner back on! I finally removed the carbs to get the carb boots in. Still don't like the way they fit. Compressed too much. I appreciate the filter arrangement on my other vintage bikes more. Except for the 1977 Honda CB550F. The airbox on that is difficult because of the carb boots. The filter is easy to change though.

Click to expand...

Once you get good at removing the carbs, that's the way to go. When changing the air filter and definitely when installing the boots, I take the carbs off. Assuming all stock parts, the boots should not be overly compressed - you may have the carb adapters on backwards.

Or consider buying one of these:


Carbs do not have to come off to remove or replace. Although it definitely helps to remove the jet holders at the bottom of the carbs. Despite it's smaller surface area than stock, it seems to work just fine!

You will of course have to do something with the oil tank breather hose. I re-routed mine to a T-connector, downward to the top of the chainguard for oil drips and also to a mini air filter up higher to help with breathing. Maybe a bit over the top, but so far so good! In case you are wondering what I did with the automatic chain oiler, I removed it and filled the feed tube on the oil tank with silver solder.

Britstuff said:

Or consider buying one of these:

High-Flow Original Lifetime Engine Air Filter - NORTON 750/850 COMMANDO

NORTON 750/850 COMMANDO,1968

www.knfilters.com

Carbs do not have to come off to remove or replace. Although it definitely helps to remove the jet holders at the bottom of the carbs. Despite it's smaller surface area than stock, it seems to work just fine!

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AFAIK, K&N no longer makes them and is selling off old stock. cNw has a similar one that is even easier as it is thinner still. https://coloradonortonworks.net/k-n-narrow-air-filter-for-amals.html

Britstuff said:

"In case you are wondering what I did with the automatic chain oiler, I removed it and filled the feed tube on the oil tank with silver solder."

Click to expand...

The chain oiler on my bike has been closed off prior to my ownership.

MLW9110 said:

Right and left was always from the perspective of sitting facing forward.

Click to expand...

Another one for you is Timing side is on the Right and Driveside is on the Left. Other bikes like recollections may vary

marshg246 said:

"You may have the carb adapters on backwards."

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Do you mean the rubber boots? I have them with the flanges on the air cleaner side.

MLW9110 said:

Do you mean the rubber boots? I have them with the flanges on the air cleaner side.

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No, each carb has a screw-on steel adapter for the rubber boots. There are three possible installations between the adapters and boots.

1) Adapter flange toward the carb body and the boot butted against it. (How I do it)
2) Adapter flange toward the carb body and the groove in the boot over the adapter flange. (How many say it should be done and makes the boot the least cramped)
3) Adapter flange toward the air cleaner and the groove in the boot over the adapter flange. (Required if using an RGM narrow air filter but not good otherwise as it makes the boot cramped)