Viton Output Shaft Seals?

ksoholm

ksoholm

Senior member
Location
Bellingham, WA, USA
Lads,

Regular nitrile seals are only good up to 210F, so I should go for viton seals for higher temp handling?

Also, whomever installed the layshaft oil seal used a smear of sealant on the outside - what do you fellers do? Dry or with sealant?

Thanks-
 
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Ok, extensive research and chatting with several seal distributors later, as our engine oil gets to 230F, it's much better for seal life to use Viton as those temps push NBR to the limit.

NBR max temps are 210F.

The 7-year-old seals in mine had done 6,000 miles and were rock hard, symptom of too high temps.

Viton it is! Of course, us BMW owners already know that from our decades-long RMS afflictions.
 
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I have seen Laverda triple oil temperatures reach 260 degrees F on a 100 degree day with the bike ridden hard. So yes Viton is better.

My record was 315 degrees on a 1978 BMW R100RS ridden in 118 degree temp. It felt like the cylinders were going to melt off the bike on to my feet. It was too hot for the alternator diode board which failed a few miles later.
 
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1200ts said:
I have seen Laverda triple oil temperatures reach 260 degrees F on a 100 degree day with the bike ridden hard. So yes Viton is better.

My record was 315 degrees on a 1978 BMW R100RS ridden in 118 degree temp. It felt like the cylinders were going to melt off the bike on to my feet. It was too hot for the alternator diode board which failed a few miles later.
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Ha, wow, them are Harley rear cylinder temps!

Did your RS have an aircooler, or was it an earlier one? I'm thinking of installing one on my very early 78 RS.
 
My record for engine heating, waiting in the Que to get into Oran Park race circuit on a 40 °C plus day with a huge crowd. Air cooled horror that day. About an hour, stopping and starting on a hill. The engine started making bad noises. We survived, but never again.
 
ksoholm said:
Ha, wow, them are Harley rear cylinder temps!

Did your RS have an aircooler, or was it an earlier one? I'm thinking of installing one on my very early 78 RS.
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No it did not have an oil cooler. I rode airhead BMW's for over 300,000 miles back when they were all I could afford. I rode 90 miles a day round trip and in the summer when it was over 100 degrees, the bike and I were both not happy. And when the bike got above 275 degrees it would start leaking oil in a lot of places. My 1978 R100RS had 211,000 miles when I sold it to get a 1979 R100RS and it was eventually replaced by a K75RS. The K bikes were in some ways worse as they would overheat and the radiator would boil over but they would never get above 250 degrees. I eventually had three different K75's.

Once the last K75 was worn out, it was replaced by a K1200RS and it was even worse. Temps above 100 degrees you had to be going at least 40mph to keep it from overheating. That was replaced by a 2008 R1200RT and it was a great bike. It did not care how hot it was and I put 154.000 miles on it in seven years.

Retired now and I still have two BMW's that never get ridden. A Laverda triple is my first choice for a Sunday morning ride.

And my record for motor temps, not oil temps. My 1950 BSA M21 (600cc side valve) on a hot day, the cylinder head temp will get to 650 degrees. The rest of the motor does not get hot as no oil is pumped up to the cylinder or head to pull heat away.
 
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