BMW K bikes (Bricks)

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bgambrogi

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Hey guys,

I've run Mobil1 75-90 in my gear box and FD for a while now in my 1985 k100rs.

I wanted to move up to Royal Purple, and I've heard a lot of people say its a solid choice, but my reservation is because on the back of the RP bottle, it says, "not for use in wet clutch vehicles such as most motorcycles." I'm guessing this is because, on the front, the RP bottle advertises that it contains Friction Modifier Additives.

My room mate is a car mechanic, and he advises that I skip anything with friction modifiers on a motorcycle.

Does anyone have any thoughts or knowledge on this topic? is RP going to cause clutch wear, change performance, etc?

Thanks all!


royal purple 75w90 in question:
http://www.canadiantire.ca/en/pdp/royal-purple-75w-90-synthetic-gear-oil-0280241p.html#.VNA9jp3F_y0

    

Point-Seven-five

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Unlike nearly every other motorcycle, the K bikes have dry clutches, and thus are not affected by friction reducing additives.

In my bikes I just throw in a couple tablespoons of 1.5 micron molybdenum disulfide powder to reduce friction and make the shifting a lot easier. I've heard that's what they use in the transmissions in the NASCAR racers. It is also used to reduce friction and heat buildup in helicopter gearboxes.


__________________________________________________
Present:
1994 K75RT
1994 K75S
1992 K100RS

Past:
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

bgambrogi

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ah!! interesting! I guess I'm good to go then. Thanks, PointSevenFive.

While I'm at it, does changing the oil in the FD and transmission tanks benefit from having the bike warmed up first, or does it not make much of a difference? The bike has been sitting for a long time, so I'm hesitant to run it without changing oil first

    

Point-Seven-five

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Transmission and final drive oil Take a while to heat up, and even then are still going to be rather thick. With the bike sitting overnight most of the oil will drain off the parts and settle in the bottom. Don't run anything, just open the drain plugs and let them drain for a while until the dripping slows way down.

If there is any metal in the drained oil, I would refill with some cheap stuff, run the bike a few miles and drain again before putting in the good stuff.


__________________________________________________
Present:
1994 K75RT
1994 K75S
1992 K100RS

Past:
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

indian036

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My bikes have benefited from the use of good quality synthetic oil at all points in the drive train, particularly in the gearbox of one. Much smoother shifting compared to whatever was in it when I got it.

Having whichever oil is being changed warm is a benefit in taking less time to drain as much as it will. There will always be some left inside, whether coating surfaces or in small pools where it can't drain from. If you don't warm it up, just leave it draining longer.

Just saw Point Seven Five's latest post. Words of wisdom.

Bill


__________________________________________________
1985 K100RT Red. VIN 0028991K100RT ENG 104EA248523386
1985 K100RT Blue. VIN 0029036K100RT ENG 104EA25852071
1990 K100LT Black. VIN WB105060310190452
1984 K100RT White. VIN. 0023022K100RT ENG 104EA32848523
    

duck

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Just my .02 on Royal Purple synthetic gear oil -

In the past I'd settled on Mobil 1 75-140 with moly additive from Guard Dog which worked fine. However, the owner of Guard Dog recently retired so he is now out of business and I was left in a quandry to find a new source for moly additive.

In poking around I discovered that Royal Purple comes with moly already in it so I decided to give it a try in a 93 K1100LT I recently brought back to life.

Having just completed a 2,000+ mile ride on the K1100LT I must say that the Royal Purple 75-140 synthetic gear oil works incredibly well in making a K transmission about as smooth as it can be. It's what I'll be using in all of my Ks from now on.

The downside is that it's flippin' expensive stuff. I found the best deal was to buy it from Pep Boys via Fleabay.


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S
14 Yamaha WR250R
http://www.ClassicKBikes.com
    

Woodie

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I've got at least 4000 miles with Royal Purple 75-90 (probably more) and I think it has improved the shifting a fair bit. I will put it in again on the next change and will go to the 75-140.


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1985 K100RT
52667
    

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