Q: We (as in my mates and I), all have old Yamaha XT500 singles in various states and conditions. We all sit down and talk about them over a beer or two and even though they’re old and relatively slow compared to today’s bikes we all still love the ‘rawness’ of an old air-cooled single with a kick-start, until it slaps the back of your leg and leaves a bruise the size of the moon!
As a rule all of our bikes are reliable except for a few spitting plugs out of the head and having to heli-coil them, and minor stuff like that, but I do have a question to run by you guys to see if you can shed a bit of light on this irritating subject.
Most of us have re-bored the motors with new rings and pistons and fitted new valve guides and seals and gaskets, to see if we can stop excessive oil use. As you know the oil is filled by putting it into the top frame rail but even after a couple of days of riding, mine especially, has dropped more than I thought it should. But there seems to be no smoke coming out of the exhaust pipe, or indeed any oil leaks from anywhere, pointing to why it’s dropped.
So do you have any idea where the oil is ‘going’? It would make a great talking point the next time we all meet, and thanks for a great site (best in SA by far), because we all log on daily for Bill’s silly, but entertaining, comments.
Chris
A: Bill says he had the same issues in England when ‘they’ all used to tear around on these bikes, and eventually they discovered in was in fact the bike’s oil pump at fault, which is interesting.
The oil pump sits at the bottom of the frame rail that holds the oil with no valve, of some sort, in-between. When the internal vanes wear, over time, the oil from the header tank seeps past the pump and straight into the crankcase, so check the level in there to see if the level inside has risen before you start the engine over night, to confirm this?
It can’t harm the motor unless the crankcase becomes over-full, which can obviously affect the seals in that area. So, if you guys want to keep the oil use back to original go and buy a brand new original oil pump and your problem is cured, simple as that. And yes, any Yamaha dealer can still get those parts for you.
