Hi fellows,i saw somewhere one story about Norton Commando and that owner told using chiansaw oil in primary side,anyone else experience about that oil,does it work there?.

I wouldn't use it as it's designed to stick and is almost like glue. It comes in different viscosities for summer or winter but a chain saw chain only lasts a couple of weeks under normal use. Chain oil is pumped onto the chain constantly and is topped up when refilling the saw with gas. A primary chain is a much finer piece and is in service much longer.

MrNorton wrote:Hi fellows,i saw somewhere one story about Norton Commando and that owner told using chiansaw oil in primary side,anyone else experience about that oil,does it work there?.

As you own two MkIII models, you also need to take into consideration the fact that correct operation of the MkIII hydraulic primary chain tensioner could be affected by a much thicker viscosity oil like chain saw oil?
Also, the tensioner depends on the lower run of the primary chain to constantly pick up oil from the bottom of the chaincase and then drop it into the tensioner reservoir as the top run of chain passes over it. If the oil is thick and tends to stick to the chain, then the tensioner mechanism may not be kept sufficiently topped up? Chain saw oil may also affect clutch operation and cause the starter sprag to slip?

I have used ATF, 10w/40 and the recommended 20w/50 oil in my MkIII's chaincase, and I would say that the 20w/50 oil was best.

I only run ATF type F in all chain and gear cases. Motor oil is for valvetrain and rotating assemblys.

I have a 1967 Mercedes Benz w/ a straight 6 and 4 speed. The manual specifies ONLY ATF for the 4 speed transmission. I try and stay, no, I do stay, with the manufacturers reccomendation, I figure they know more about the machine than I do.
kurt

I use ATF Type 'F' in my primary for two reasons:

Ford type ATF was designed for their old automatics which used bronze plates. My 850 has bronze clutch plates

ATF is red - easy to tell if your primary is leaking and - more importantly - its easy to tell if the crank seal is leaking motor oil into the primary. When this happens, the ATF is no longer red.

BillT, greetings. Even without leakage in, does it stay red? I would have thought that friction materials from the clutch plates would turn it "dirty" pretty soon in any event, but would be curious. Thanks - BK

BrianK wrote:BillT, greetings. Even without leakage in, does it stay red? I would have thought that friction materials from the clutch plates would turn it "dirty" pretty soon in any event, but would be curious. Thanks - BK

After I replaced my crank seal last January, I used the ATF, and I changed it in August after my primary chain broke (change was original, AFAIK). ATF had about 6000 miles on it and still looked red. Very little in the way of bronze in the fluid, and the clutch plates still look good.

Since its only 7 oz, I'm planning to change it on a 6000 mile interval, or maybe every other oil change.

Good to know re the ATF, thanks Bill.

How many miles on that primary chain? Did it give any warning, or just go? Do any damage? (He asked, fearing the answer....)

Chain saw oil has "way Tack" properties designed to KLING to metal surfaces like chainsaw chains and lathe beds. Keep this stuff out off your primary. If it gets into the clutch, it will most definately disruped its operation and require dismantling, cleaning and maybe friction plate replacement.
I also use ATF type F. It is fairly cheap, a pretty red color and I do not mind changing it whenever I get the urge. All we're trying to do here is lube the chain and this stuff is outstanding for this purpose. The clutch in meant to be dry and because of the particular properties designed into ATF, it does the less of all oils to polute the clutch system.

I also generally use ATF if it's for a chain drive, rather than belt drive primary case, however anyone with a MKIII 850 (like MrNorton who posted the original question) would do well to heed L.A.B.'s advice about the hydraulic chain tensioner requiring a more viscous oil to keep it working properly.

KWB210, what model Mercedes do you have. My daily driver is a 67 200 4 speed. Norton content- my Mercedes has peashooter mufflers. The neighbors say "I heard you leave, was that your bike or your car".
ATF makes an excellent standard trans fluid. Automatic transmissions are full of gears also. Been running it in my Commando forever. I do splurge for the synthetic trans fluid for both my bike and car. James

BrianK wrote:Good to know re the ATF, thanks Bill.

How many miles on that primary chain? Did it give any warning, or just go? Do any damage? (He asked, fearing the answer....)

My primary chain failed without warning. I was traveling down I-95 in southern Palm Beach County, about 10:30 at night, and doing about 4500 RPM. Nobody was on the road within a 1/2 mile of me, and the highway is 5 lanes wide at that point. I rolled on a little more throttle, and at just about 5000 RPM, I heard a distinct metallic 'tink', and the motor started revving freely. I figured I had thrown the drive chain, and coasted over to the side of the road. I put the bike on its center stand, and saw the chain was still on. Shutting the bike off, I ran the tranny through the gears while spinning the rear tire, and got almost no resistance. Figured at that point I had either snapped the main shaft on the tranny or broke the primary chain. As far as I know, the chain was original to the bike, which sat, disassembled, in various garages for over 20 years before I got it.

Once the bike was home, I found the primary chain neatly piled between the two pulleys in the case. No damage to the case, the pulleys, or the stator. Inspection of the chain showed one of the plates had apparently failed, as the edge of the break did not look new. Two other plates on that same link had fresh breaks at the same point - the thinnest part of the plate, at the top and bottom of the pin hole. The last plate was intact but deformed, having pulled off of the end of the pin.

I thought I was real lucky, having the chain be the only damage, but analysis of the system would show that the most stress is at the point where the chain comes off the clutch drum. While on either pulley, the load is spread over all of the rollers on the pulley, and the bottom loop of the chain is slack. It is only when the chain comes off the clutch drum that the row of links goes from a distributed load to a direct load, and is the most likely point where failure would occur. I think it would be pretty rare for a primary chain to cause damage to the crank or crank case, though I could see where the chain could end up wrapping around the clutch drum and damaging the primary case or transmission.

When I broke one the only real damage was to cut the stator wires. I was also cruising but that bike had been raced and truly beaten for several summers. At that time of my life I was very hard on equipment.