Engine and gearbox oil grade, opinion

[zoltan]

Just ordered a 10000mile service kit from Motoworks for my 95' R100RT ( with 27400 miles) and the chap recommended me the Millers 20w50 and gearbox oil 80w90, my mechanic recommends 10w40 for engine and 75w90 for gear box there is a few £ difference between the two. Surely it doesn't make huge difference in this country ( I don't ride in the winter), I used to put in the engine whatever was cheaper ( 25 years ago ) in the shop . I will go with my tech advice ( BMW mechanic ) , but wonder what you guys use are you price sensitive or use the best there is ?

 

[Kenny]

Motorworks have it right

 

[John Armstrong]

Motorworks have it right

My opinion too

 

[Timpo]

Miller 20w50 and EP80/90 sounds good to me.

 

[DrFarkoff]

Whatever Gear oil you use make sure it's GL5 spec!

But I go with the above 20W50 and 80/90 GL%

 

[John Armstrong]

Save the £'s from buying cheaper off spec stuff in a gearbox overhaul fund

 

[Beemerboff]

Its 2012

I always put in what BMW currently recommend, and that is the best quality full synth 20/50 for the motor, and full synth 90/140 GL5/6 for the box - a box will last twice as long between overhauls with synth.

And I find a crash helmet is better than a cloth cap on backwards too.

 

[Kenny]

Sorry must disagree re fully synth for engine oil....everyone has used 20/50 mineral oil for half a century Gearbox should be GL5 minimum. I put synth. oil in the gearbox and it leaked past the new seal

 

[fayeslane]

I reckon regular oil changes of the engine and drive train using the correct grade is more important than the type of oil used. Same goes for fork oil & brake fluid.

 

[electric_monk]

Sorry must disagree re fully synth for engine oil....everyone has used 20/50 mineral oil for half a century Gearbox should be GL5 minimum. I put synth. oil in the gearbox and it leaked past the new seal

Agreed, the one time I left the bike into a mechanic to change oil, he put in semi-synth. The engine leaked like a sieve through pushrod seals etc. Once I found out and changed to mineral oil the leaks disappeared.

 

[Beemerboff]

I've put synth in everything I have owned since it became generally available , and never had it leak from anything, not even the Beesa.

The starter sprag clutch on my Honda wouldnt work with it however, it was just too good a lubricant for a device which relies on friction to operate.

I dont doubt that dino works OK, and has done so for a long time, but synth is just a better product in every way, and will give less wear, better high temp performance, stays in grade longer, and will cost no more than changing a cheap oil twice as often.

Just like a modern crash helmet works better than a cloth cap- the cap works OK most of the time, but when you need it you will be glad you have a helmet, and good oil is the same.

 

[Sunny Jim]

Going to change the gear box & bevel box oil this week - anyone use anything different for the 2 x boxes? (Manual sits with 80w90/GL5 spec).

 

[John Roberts]

Interesting about synthetic oil resulting in leaks, is that often/usually the case, or just occasionally? If one reverts to using normal non-synthetic oil would any leak then stop?

I rather fancy giving it a go.

 

[Sunny Jim]

Rock Oil 80w90/GL5 @ £15.00 + VAT for 5 litres (Don't do less!)

Any reservations on Rock Oil anyone?

 

[(RIP) Arkwright]

Rock Oil 80w90/GL5 @ £15.00 + VAT for 5 litres (Don't do less!)

Any reservations on Rock Oil anyone?

No, it's the best, and they make a proper mineral 20W/50 as well as a 80/140 GL5 which is good in bevel drives and slightly worn gearboxes!

 

[Sunny Jim]

Thanks Arkwright - question is what do I now do with 3ltrs excess

 

[(RIP) Arkwright]

Thanks Arkwright - question is what do I now do with 3ltrs excess

Keep it for the next oil change, I only buy gear oil in 5l cans and engine oil in 25l drums, the way oil's going up at the moment it's a good investment!

 

[Martin.]

At60,000 now, my R100Gs is using a bit of oil. In nearly 5,000 miles to Estonia and back, I reckon on having used about 5lts.
I had to use 15/40 sometimes as 20/50 was hard to find. However, it was suggested I try 10/60 as this is more viscous and my slow down the oil loss.
Any ideas?
Not sure whether it`d be too "Thick".

 

[(RIP) Arkwright]

It's probably ready for a set of piston rings and exhaust valve guides.........they're both straight forward to do!