Oil is still one of the black arts. There are a lot of speculation and a lot of questions about what goes into your motorcycle. At Darwin Cycles we use Spectro because the quality of the product. We spoke with Rollin Karoll of Spectro for some additional clarification.
Question 1: Can viscosity grades be mixed?
Spectro Answer: Yes, you can and no harm will be done. Topping up with 10w40, if its all you have available, will not injure the 20w50 in your crankcase. It will, however, lower the overall viscosity of your crankcase oil to a certain extent. This will cause no harm to your motorcycle. Likewise, adding a 20w50 product to 10w40 will slightly increase the overall viscosity in your crankcase. Again, no harm will occur.
Question 2: Can you explain multi-weight lubricants?
We have added a long over due bike category this year. It is a show that you do not even have to enter and the prizes are awesome.
For years I have noticed a type of bike I really enjoy seeing at the Smoke Out but there has not been a way to recognize these bikes at the event. It starts with a stock bike and you fix the initial things that have to be addressed. So maybe you got a Sporty in 1999 and rejetted the carb, replaced the air cleaner and pipes, put on a comfortable Mustang seat and called it a day.