Strange sludge under front engine case. R51/3. Pictures.

[miller6997]

I used Castrol GTX 20-50 for decades with no ill effects. I only switched to Valvoline 40W very recently because Vech recommended it and because I was bored.

[Micha]

)

Thanks.
I also heard horror stories about the damage modern oils have done to our old engines. Do you have any mistakes or information to teach us?

Someone in the engine oil field gave me a tip to go with MOTORBIKE 4T 10W30 oil.
What do you guys think?

[schrader7032]

Is 10w30 OK for your bike? Seems like it should have a higher multi weight beyond 30...possibly 40.

Amazon shows the specs for this oil to be API; SL; JASO; MA2. The SL rating is troublesome, but I did some testing of a range of oils a number of years ago. I did test Liqui Moly Motorbike 4T 20w50. It had mid level amounts of ZDDP, a total of about 1700. There were handful of oils tested with about those numbers. Only the Spectro product, along with BMW's oil sold at the time and Valvoline VR1 had ZDDP levels over 2000.

I don't know where the 4T 10w30 is in terms of ZDDP.

[mcsherry1328]

Just use Valvoline VR1 40 weight and you will be totally satisfied with the oil performance . You can buy it at NAPA auto supply stores.