Cavy
Well-known member
This may have been covered before but I just found out.
I was reading in NEPRTS about oil filters and descovered something I was not aware of. The factory Yamaha oil filter does not have a bypass valve in it. This caused me to look in the repair manual to see the way oil is dispensed throughout the engine. What I found is that from the oil pump the oil goes directly to a pressure regulating valve which dumps excess oil pressure back into the sump. The pressurized oil then goes to the oil filter (with no bypass) and then to the bearings and the rest of the engine. What this means is if the oil filter becomes restricted it will stop the flow of oil to the engine causing low oil pressure. In a normal engine this would cause the oil pressure switch to turn on a warning light to alert you. Except these engines are not equipped with a low pressure switch, only a low oil level switch. (At least I could not find one mentioned) This would allow you to be riding around with low oil pressure and not be aware of it because the oil level would still be ok. This would seem to be the best reason to use an aftermarket oil filter (with a bypass valve) that I could think of. At least then if the filter got restricted it should bypass and keep sending oil to the bearings. I am having trouble believing Yamaha would have let this slip by them. Am I missing something here?
I was reading in NEPRTS about oil filters and descovered something I was not aware of. The factory Yamaha oil filter does not have a bypass valve in it. This caused me to look in the repair manual to see the way oil is dispensed throughout the engine. What I found is that from the oil pump the oil goes directly to a pressure regulating valve which dumps excess oil pressure back into the sump. The pressurized oil then goes to the oil filter (with no bypass) and then to the bearings and the rest of the engine. What this means is if the oil filter becomes restricted it will stop the flow of oil to the engine causing low oil pressure. In a normal engine this would cause the oil pressure switch to turn on a warning light to alert you. Except these engines are not equipped with a low pressure switch, only a low oil level switch. (At least I could not find one mentioned) This would allow you to be riding around with low oil pressure and not be aware of it because the oil level would still be ok. This would seem to be the best reason to use an aftermarket oil filter (with a bypass valve) that I could think of. At least then if the filter got restricted it should bypass and keep sending oil to the bearings. I am having trouble believing Yamaha would have let this slip by them. Am I missing something here?
