Bike Oil

[Anonymous]

This may come across as a novice's question, and it is. What exactly is bike oil, and what separates it from auto oil?

Thanks in advance.

[Pete's GS]

Wow, there's a can of worms ! Basically, if you're riding a GS you don't have to worry about motorcycle-specific oils. There's a small difference in the zinc and phosphorus levels in the motorcycle-specific oils. They have higher amounts of these anti-wear additives than do automotive oils. The EPA wanted to lower these additives because they can contaminate catalytic converters. The Japanese equivalent of the American API (JASO ?) believes these higher anti-wear levels are justified in motorcycle engines but other independent research doesn't support that conclusion. Triumph requires motorcycle-specific Mobil 1 at $8/qt or litre, and that tends to annoy the Trumpet crowd.

I have come around to believing that synthetic oils are worth the extra expense. My XS650, which is notorious for dragging clutch plates, shifts very well on Castrol Syntec full-synth. Plus, you can go 2 or 3K miles between changes, so the cost works out about the same as using a conventional oil and changing it at every 1K miles. So for a GS I would use any oil you like that is NOT energy-conserving. You might get slipping clutch plates otherwise. Some people report less valve gasket seepage using 20W-50 than the usual 10W-40. Whatever you choose, just change a conventional oil every 1K- miles or a full-synthetic at 2 or 3K.

[Anonymous]

Thanks Pete. I kind of suspected as much, but it doesn't hurt to get the nuts and bolts.

Also enjoyed the XS650 reference as that's what I cut my motorcycle teeth on. I thought about selling it after getting the GS850, but as one of my friends explained to me, the only better that having a motorcycle is having two.

Concerning the synthetics, the fellow who gave me the XS650 avoids synthetics. He's under the impression that they cause slight swelling in the gaskets, etc. so that if the user ever switches back to natural oil leaks will result. At least I think that's his reasoning. Anybody heard anything like that?

Thanks again.

[Detman101]

Yes, that happened to me with my pontiac sunbird. I heard about the synthetic oils one day and decided to do an oil change with the synth stuff after only using dino-juice.
About 2 days into the synthetic my car started leaking oil around the rear seal and the valve cover gasket. I took the car to a mechanic and had the seals and gaskets replaced and asked him what could have caused them to just go out like that when the car had never leaked a drop of oil in 10 years it has been running/manufactured. He asked me if I had jumped it off a hill or done anything radical to it lately. I told him that I switched to synthetic oil and he said "Ah ha!!". That, apparently, was the thing that made the gaskets and seals start to leak. The regular oil builds up a protective kind of "Build-up" around seals and gaskets so that if they deteriorate the layer of old oil-crud is there to support the missing gasket/seal and keep leaks from happening. When you introduce synthetic oil into a vehicle with this sort of build-up the synth oil scrubs away the buildup and you get leaks.

Hope I explained my experience clear enough...


Dm of mD

Edit: Needless to say, you couldn't get me to put synthetic oil in anything that isn't brand new fresh off the factory floor. There isn't anything worse than your older vehicle losing a quart of oil a day because of oil leaks.

[Pete's GS]

I have heard about switching back to conventional oil after using a synthetic causing leaks. BMW and Triumph both install Mobil 1 at the factory so their oil changes tend to be sky-high.

BTW, keep the XS ! I have two bikes, my much-Minton-modified XS650 and a GS550. Both are 1980s and really different from each other. I like them both but the XS has less trail than the GS and steers faster. Plus, it's just a blast to ride !

[Giblet]

Oil

Pete,

Can you give me a specific symptom of clutch slippage (i.e. what does it feel like?). I use the same Mobile 1 I use in the car.

[Pete's GS]

Well, starting from a dead stop it will take more than the usual amount of revs and feeling for the friction zone to get going. I noticed it on my CB750 when I was going down the fwy about 60 mph--back when the speed limit was 55--gave the engine some gas and it revved 3 or 400 rpm but the speed didn't change at all. Put a Barnett in after that and no problems. I always wondered if it was caused by putting some Kalgard (a then-popular MdSO2-Molybdenum di-sulphide-oil additive) in.

[Giblet]

Bike Oil

My 1100GK "bogs" a bit when I crank the throttle hard at highway speed but not at take off. I run the same Mobil 1 I run in my truck/car. I think I still have some carb work to do. Got them cleaned and synced, but number 1 or 2 cylinder is still off a bit.