NO! I'm NOT starting an oil thread, God forbid! Just a question. I have always used Amsoil products in my motorcycles. After the first oil change at the dealer, I wanted to go Amsoil oil and their WIX filter. I noted in their product guide that Amsoil had no listing for an oil filter for a 1200cc Speedmaster, only the old 865cc. I did see that they had a WIX filter for the Bobber 1200cc (# WL10000). I figured, same engine, so I ordered it. I thought I'd drop Amsoil a line (email) and let them know that they should update their oil filter product info to include a filter for the Speedmaster 1200cc, since I saw none. They got back to me by email and said the 1200cc Speedmaster should use the WIX 31538 filter. So, I ordered it and asked if I could return the WL10000. Three emails, no response. However, looking at the two oil filters, they are different. The 31538 is longer than the WL10000. Does anyone know if the WIX 31538 is, in fact, the correct filter, or should it be the WIX WL10000, or are they interchangeable and it doesn't matter even though there is a slight difference in size?
