Oil for '85 k100 rs

OK, on a serious note, Paul Glaves points out in this months ON that most automotive oils have had the zinc anti wear additives ( ZDDP) greatly reduced (on any thing rated above SG) to protect catalytic converters.

This lack of zinc causes problems with flat tappet pushrod engines (cam and lifter wear). We have overhead cams so are not as affected by this problem (sorry Airheads).

If you want to be extra safe you can buy zinc anti wear additives (I use one by Red Line Oil). I use 1/3 bottle per oil change. If I remember correctly, it's around $12/ bottle. (I want to get 350,000 miles like Paul).

http://www.redlineoil.com/products_motoroil.asp?productID=122&subCategoryID=1&categoryID=1

Thanks for informing us on that, Lee. I'll look for the Red Line additive as it sounds like it certainly can't hurt.

A friend of mine, though an airhead rider, has nearly 300, 000 miles on his bike using plain ol' car oil. One top end since new. I use motorcycle specific oil myself. Still, 300,000? Makes a case for the car stuff. Oil threads. Gotta love 'em.

jamesdunn said:

A friend of mine, though an airhead rider, has nearly 300, 000 miles on his bike using plain ol' car oil. One top end since new. I use motorcycle specific oil myself. Still, 300,000? Makes a case for using the right amount of the slippery stuff. Oil threads. Gotta love 'em.

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fify.

really, it's correct SAE grade & weight.

I think motorcycle specific oil is nothing more than a marketing ploy to get more money for the same product. They even do it with "special" oil for 4X4s, SUVs, trucks, etc.

I would wager you could take the pistons and bearings of similar size from a motorcycle, car, gasoline lawn tractor, etc. and if you put them together, you could not tell the difference. I rebuilt a diesel Ford 801 farm tractor a couple of years ago and the parts looked exactly like the inside of old Falcon and Mustang 144 and 200 engines I used to overhaul.

The brick K-bike engine is pretty much a car engine laid on its side. The airhead engine looks an awfully lot like the old VW bug engine with two cylinders missing (and both are German). The oilhead and hexheads are updated versions of the original airhead. Motorcycle engines are generally understressed when compared to car and truck engines because they have a much more favorable power to weight ratio.

I've had over 15 motorcycles over the last 35-40 years and have yet to buy my first drop of motorcycle specific oil. I have never had an oil related problem and have nobody else that has had a problem either.

I do have 4X4 specific oil synthetic in my Impala because it was on closeout and was cheaper than dino car oil.

Ken

98lee said:

This lack of zinc causes problems with flat tappet pushrod engines (cam and lifter wear). We have overhead cams so are not as affected by this problem (sorry Airheads).

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Our overhead cams still have flat lifters, so the need for an anti-scuff additive would seem to apply to us as well.

Kayseventyfive said:

Our overhead cams still have flat lifters, so the need for an anti-scuff additive would seem to apply to us as well.

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There are NO lifters. The cam actuates the valve directly through the bucket and shim. Our spring rates are lower compared to the rates needed to control the extra mass of the lifter, pushrod and rocker arm.

We have the same setup that most OHC automotive engines have today. That is what today's oils are designed for. Todays engines are either OHC or roller lifter pushrod engines.

Most oils still have around 800-1100 ppm of ZDDP. Adequate (I would prefer more) for OHC engines. Around 1500+ ppm are required for non roller (flat tappet ) pushrod engines.

That being said , since we DON"T have catalytic converters, adding some extra anti-wear zinc compounds to the oil (as I do) can't hurt .

osbornk said:

I think motorcycle specific oil is nothing more than a marketing ploy to get more money for the same product.
Ken

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For a lot of bikes, motorcycle specific oil IS required. Not for the protection of the engine , but for the protection of the clutch. MOST bikes have a WET clutch. The oil that is in the engine bathes the transmission and the clutch.

Remembers what happened when your '67 Camero developed a rear main seal leak and coated you clutch disc in regular engine oil? Putting oil with the wrong coefficient of friction into a bike's wet clutch can cause all kinds of unintended consequences.

Luckily we have DRY clutches like a car so motorcycle specific oil is not required. The only issue is viscosity vs. operating temperature and cam anti- wear properties as related to grades. All good oils, changed regularly will protect your bearings.

98lee said:

For a lot of bikes, motorcycle specific oil IS required. Not for the protection of the engine , but for the protection of the clutch. MOST bikes have a WET clutch. The oil that is in the engine bathes the transmission and the clutch.

Remembers what happened when your '67 Camero developed a rear main seal leak and coated you clutch disc in regular engine oil? Putting oil with the wrong coefficient of friction into a bike's wet clutch can cause all kinds of unintended consequences.

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I guess I was just lucky because my first 11 motorcycles had a wet clutch and I had no problems of any kind. I might be different with high performance bikes.

98lee said:

There are NO lifters. The cam actuates the valve directly through the bucket and shim.

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Yeah, I should have called it a cam follower, as BMW does. All this lifter, tappet, bucket stuff are just different ways of describing the part that rides on the cam and opens the valve. However, the action of the cam lobe on the bucket follower is a wiping or rubbing action rather than what a roller cam would have. Most of the literature makes the distinction between roller and and flat tappets with regard for the need for zddp, but no mention is made of OHC bucket setups. I have not seen any specific info, yea or nay on DOHC bucket follower needs for zddp. Please share if you do.

Certainly, as you mention, owing to the lower spring pressures, a DOHC setup does have lower oil film loading than a pushrod and rocker arm valve gear. So, it would follow that there would be less scuffing and there could be less of a need for higher levels of zddp. High rpm operation is someitmes mentioned as increasing the need for zddp. We would seem to be somewhere in between the pushrod and roller follower engines.

A number of sports car racers with DOHC bucket valve actuation believe in ZDDP, so I play it safe and use zddp. But, hard information is hard to find.

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