What Did You Do With Your Commando Today?

I am still running the stock bronze plates that came from the factory after 46 years + ownership and running the right oil in the primary they are working fine my Norton has over 160k miles on it as it was a everyday day rider for most of its life, I only replaced the clutch centre once in all that time over 13 years ago so really not bad at all, my clutch is light and can use one finger operation if I wanted to, so to me I have no reason to put in Barnet plates or any other plates for that matter when the bronze ones are long life and doing their job so well.
 
Fired the bike up today after the winter layup. Although it was, to me, a cool day I still rode 50 miles. The only issue I had is oil appears to be leaking from my oil tank cap. I’m on a quest to stop all oil leaks so I’ve already replaced the cork gasket on the cap. Obviously it didn’t take care of the problem. I have an extra gasket that I will install and see if that does the trick. I’m not hopeful. I’ll probably end up ordering a new cap. Other than that the bike ran great. The weather forecast for the next several days is shitty. Cold and rainy so no riding for awhile.
 
I’m on a quest to stop all oil leaks so I’ve already replaced the cork gasket on the cap. Obviously it didn’t take care of the problem. I have an extra gasket that I will install and see if that does the trick. I’m not hopeful. I’ll probably end up ordering a new cap.
Are you screwing the cap down tight and not just latching it?
 
Fired the bike up today after the winter layup. Although it was, to me, a cool day I still rode 50 miles. The only issue I had is oil appears to be leaking from my oil tank cap. I’m on a quest to stop all oil leaks so I’ve already replaced the cork gasket on the cap. Obviously it didn’t take care of the problem. I have an extra gasket that I will install and see if that does the trick. I’m not hopeful. I’ll probably end up ordering a new cap. Other than that the bike ran great. The weather forecast for the next several days is shitty. Cold and rainy so no riding for awhile.
You may have already have mentioned this but anyway do you have a breather valve fitted. I use the one JS Motorsport sells and fit it to the engine breather. I imagine from the way it looks it has something like the BMW airhead spring steel reed valve inside. I use them on both my Nortons and not a drop of oil escapes. (that's a CNW starter behind it in the photo). If you have access to a lath you can get the BMW valve very cheaply and make up a sealed cup type fitting to mount it in. That's what's on my Dommi.
 

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Are you screwing the cap down tight and not just latching it?
I believe I’m screwing down the cap properly. I line up the indents, seat the cap fully and turn til it won’t turn anymore. I know that the cap is spring loaded so maybe that may be the issue.
 
You may have already have mentioned this but anyway do you have a breather valve fitted. I use the one JS Motorsport sells and fit it to the engine breather. I imagine from the way it looks it has something like the BMW airhead spring steel reed valve inside. I use them on both my Nortons and not a drop of oil escapes. (that's a CNW starter behind it in the photo). If you have access to a lath you can get the BMW valve very cheaply and make up a sealed cup type fitting to mount it in. That's what's on my Dommi.
I do not have a breather valve installed. I have a mk3 with the breather tube coming off the left rear of the timing chest. Please explain how this valve would benefit me and exactly how it works. Thanks.
 
I know that the cap is spring loaded so maybe that may be the issue.

When the oil filler cap is screwed down it should fully compress the light internal spring between the cap and the inner plate holding the dipstick so the gasket should then be clamped tightly to the filler neck.
 
When the oil filler cap is screwed down it should fully compress the light internal spring between the cap and the inner plate holding the dipstick so the gasket should then be clamped tightly to the filler neck.
That is how I understand it is supposed to work. Something is causing this leak.
 
There have been previous reports of persistent leakage from the oil filler cap that seem unexplained.

I haven't had this problem myself so I can't think what could be the cause of it if the gasket is sealing properly. Maybe try a thicker cork etc. gasket?
 
I do not have a breather valve installed. I have a mk3 with the breather tube coming off the left rear of the timing chest. Please explain how this valve would benefit me and exactly how it works. Thanks.
Hi.

These breather valves are a one way reed valve control. So positive pressure built up in the motor with piston movement is expelled through the valve. It then closes and prevents air flowing back into the engine as the pistons move up again. It is the simplest of device. Just an aluminium disc with a hole in it cover by a piece of thin spring steel which opens under positive pressure and closes under suction. The manufacturing cost is mostly in tge housing unit.

My experience is that it almost totally eliminates leaks from the lower half of the engine. For example I raced a 500 twin with a catch tray below the faring. The catch tray always stayed clean and dry during racing. However annoyingly if the bike was parked with oil still in it over winter it wet sumped and eventually leaked from the crankcase joint half way up the front of the crankcase. So even on a bike which did have a leak at the crankcase joint while the motor was being raced at 7000 rpm nothing came out.

It is not targeted at the oil tank as this normally has a simple breather vent so it may not improve your problem but if your after an oil tight motor I can recomend them.

Many other people report positive results and as I mentioned BMW airhead motors run an identical valve.

On a race bike using Castrol R you need to clean it every now and then because castor oil tends to be rather sticky and can basically glue the valve closed. Not a problem with normal oils.

I have attached a photo I found online of the BMW valve. Its very simple
 

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There have been previous reports of persistent leakage from the oil filler cap that seem unexplained.

I haven't had this problem myself so I can't think what could be the cause of it if the gasket is sealing properly. Maybe try a thicker cork etc. gasket?
The Cork seems to compress over time. My leak from the cap was cured by replacing the Cork seal, like for like.
 
Maybe overfilling the oil tank or too much pressure in the tank from your motor breather return, oil tank breather blocked or restricted, use a thicker cork gasket, just a thought.
 
With the cap in my previous picture screwed down it's just over the halfway position of the neck 'ramp' so still has some twist left to go if the gasket should compress any further although I don't think it has in a long while.

What Did You Do With Your Commando Today?
What Did You Do With Your Commando Today?
 
Well today was bright and sunny so I decided to clean up the oil on my bike from the tank cap leak. I got that all cleaned up and then installed a second new cork gasket on top of the first. I paid particular attention in installing the cap properly. I then went on a 15 mi ride to the gas station and back. Inspected for leaks and found none. This was some pretty spirited riding around 80-85 mph so even though 15 miles isn’t far it was robust. No leaks so far. I’ll just have to keep an eye on it.
 
I rebuilt my clutch with new Barnett plates, a new clutch centre that I bought 40 years ago, and a "CLUTCH LOCATION NUT WITH SMALL GARTER SEAL FOR PUSHROD, COMMANDO" from RGM https://www.rgmnorton.co.uk/buy/clu...mall-garter-seal-for-pushrod-commando_604.htm . This looks like it will be a very effective seal between the gearbox and the primary drive / clutch.

It took me 4 tries before I discovered some instruction on the RGM site, it all fits together much better when you read the instructions :rolleyes:
 
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