engine oil

Cany anyone tell me what the best weight engine oil is for a 71 / 750 roadster and how much it should hold ?

this might help: oil-change-question-t6754.html

as youl see everyones view is slightly different as long as u cover the basics, have a read!

http://www.nortonclub.com/docs/OilTemp.pdf

Lot of material on this topic. I happen to like this one.

Good Luck, Good reading.

Norton put out a tech sheet in the mid 70's stating that straight 40 wt was now recommended for the Commando. Straight weight oils do not lose their viscosity fairly quickly as multiweights do. That was true in the 70's and it's true now.

That might be great in chilly England. However, summertime temperatures are extreme here in Western Australia. I now use Motul 20W50 and make sure I keep on top of oil changes. I'm now going to a change every 1000 miles. I have run my Norton in temperatures up to 48 degrees C. Somewhere around 120F to you guys over the pond. I was living in the Pilbara region in our north west at the time. Winter temps here are quite moderate for year round riding.

Well, in high temps there is no reason at all to use multiweight because the W aspect of the oil is just reducing your 50wt viscosity after a few hundred miles or so. I can't see how the average motorcycle can benefit from multiweight since most bikes are not ridden in cold temps and that's what multiweights are for - to aid starting in cold weather. They have no other function. If you are really concerned that straight 40 is insufficient, use straight 50. It will actually STAY at 50!

Ooooh ooooh an oil thread!

20W-50 per the rider's handbook has worked for me for 35 years. Used to be Castrol, but now I use Valvoline VR1 racing oil (has zinc in it for flat tappets).

3 quarts if your engine has an external oil filter, a bit less otherwise.

MexicoMike said:

Well, in high temps there is no reason at all to use multiweight because the W aspect of the oil is just reducing your 50wt viscosity after a few hundred miles or so. I can't see how the average motorcycle can benefit from multiweight since most bikes are not ridden in cold temps and that's what multiweights are for - to aid starting in cold weather. They have no other function. If you are really concerned that straight 40 is insufficient, use straight 50. It will actually STAY at 50!

Click to expand...

Mike,

I had an oil analysis done around 1100 miles on straight 50 and 20w50 and the 20w50 held its viscosity just fine. I'm going to try again at 2000 miles, but it looks like Norton engines don't shear the oil down like they say. 20w50 will protect the engine better at startup. This is in July and August in North Carolina, highs in the mid and upper 90's.

Eric

Perhaps the fact that our gearbox is separate from the engine means it is not subject from shearing from the gears.

Another feature turned benefit of non unit construction!

Just thought I'd add my two pennys worth. Ran commandos for 30 years and when I was younger could'nt afford good oil but as I worked for good old British Rail as a fitter I used to use the same engine oil as they used in the Locomotives! It was Shell Rimula 20/50W for Diesels. Never had an engine problem.
More recently I've been using Castrol RX fleet 15/40W which I buy in 25l containers. I use this oil in my commandos, Laverda Jota, Suzuki 1200 Bandit and my Mercedes C250 Diesel to no ill effect. I think its important to use a decent oil and do regular oil changes, but the regular oil change is so much more important than the oil!
When I worked for BR the shell rep said that oil for diesels and oil for petrol engines were the same and I had access to a lab for testing viscosity etc .,oil was always in spec at oil change time. incidently the Castrol RX fleet oil says on the drum for diesel and petrol engines and the castrol rep says that it is the same formula as GTX.
Everyone has their own opinion on this emotive subject but my honest advice is just use a good quality multigrade and 1000 mile oil changes and keep levels topped up after all any oil is better than no oil at all!

Maylar wrote:

Ooooh ooooh an oil thread!

Click to expand...

You watch, it will morph to wet sumping by the second page.

Diablouph said:

Maylar wrote:

Ooooh ooooh an oil thread!

Click to expand...

You watch, it will morph to wet sumping by the second page.

Click to expand...

And a breather one by the eighth page.

yeah . . . . what's wrong with oil in the sump? my other bikes have oil in the sump . . . and . . . . where should I drill a hole for that hose barb with internal nut and washer for my breather hose? . . . .

I love the smell of Norton oil in the morning. It smells like victory.

Here is an interesting thread from another forum

http://www.ducatimonster.org/forums/tec ... r-oil.html

There are a few interesting things that I got from it (well my interpritation of the first 20 pages anyway)

Group 4 and 5 synthetics are essentialy a mono grade oils that do not change in viscosity as much mineral oils at lower temperature, therefore they do not require the viscosity modifiers that mineral oils do, making them more stable over time etc

Oil companys do not specify what the base stock is, however it can be guessed at by the pour point, the lower the more likely it is to be a group 4 or 5 base

Car formulated oils are made to certain emission and performance specs that are not nessesarily optimum for air cooled bike engines

Other than motorbike specific oils Synthetic diesel engine oils are probably the next best thing, and by the sound of it not that far behind, they are still allowed the good anti wear compounds - ZDDP

In saying all that fuel dillution could make any of the oils useless in the same sort of time frame

myjota said he used Shell rimula. I think in the USA it is now Rotella T. Yes it is speced for diesels but it is great especially for break in apps. It is in my SBC as i just installed a new cam. So far so good. I'm running 15w/40 and that's what I plan to use to break-in my new Norton engine. Rotella still has zinc. Breakins and old stuff need zinc. I'm pretty sure it is available in 20W/50

We made it to page two!

So, what is the best oil for wet sumping combined with a one way breather and electronic ignition?

highdesert said:

We made it to page two!

So, what is the best oil for wet sumping combined with a one way breather?

Click to expand...

5 w 140 looks good to me. the 140 will help stop the wet sumping and the 5 will let it pass through the reed valve very easy :mrgreen:

yet another article on oil for old bikes and it specifically mentions Commandos is at http://www.realclassic.co.uk/techfiles/oil030319.html
anyway, based on that bought some Mobil V Twin 20W-50 and am going to give it a try, especially since we've had an extreme heat wave locally :twisted:

108 here in long beach today, Sorry to admit I was on the Triumph. You could really bake bread on the porch, 7:25 and it's still 96. :shock: