wrong oil

I filled my kz440 ltd with regular motor oil. Then I read here that you shouldn't use today's motor oil with older, wet-clutch bikes. I didn't run the engine, but the oil sat in there for a couple of weeks. Should I flush the engine? Or should I just do two or three successive oil changes? I drained the oil last night, and it came out a lot darker than it went in, so I'm thinking a flush couldn't hurt. I've got kerosene on hand. Is it okay to use that, or is diesel preferable? Thanks.

I would refill it with Shell Rotella T 15W40 Motor Oil and ride it a while, if the clutch seems to slip drain it again and refill with more Rotella.
I think you will be fine though.
How old is the clutch?

Car oil just sitting in it for a few weeks should not cause any problems. Don't put in kerosene. Just put in correct JASO-MA compliant oil and ride it. Ed

I just bought it in December, haven't ridden it yet. I assume the clutch is original. Okay 650ed, I'll add the correct oil, but as for riding...I live in Maine, so I'll have to wait until the glacier recedes.
Thanks.

I agree, Kerosene might attack the plates or have an adverse reaction on rubber parts.
Steve

If it was a KZ1000 or something, I would replace it. However....
Exactly what oil did you use & does it have the Energy Conserving Seal on it?

Others may not agree, but If it doesn't have the seal, I don't think regular/conventional car oil is going to hurt the motorcycle if you ride it for a few hundred miles or so. (oil without the friction modifiers)

Energy conserving oils are also known as Resource Reducing and have friction modifiers that supposedly cause the clutch to slip & they don't have the anti-wear ingredients found in motorcycle oils or heavy duty oils (Shell Rotella or Chevron Delo). The energy cons seal is usually found on lighter grades (5W-20, 5W-30, 10W-30), so your oil may not have the seal.

gwyon wrote: I just bought it in December, haven't ridden it yet. I assume the clutch is original. Okay 650ed, I'll add the correct oil, but as for riding...I live in Maine, so I'll have to wait until the glacier recedes.
Thanks.

We just had rain and hail yesterday. Snow on the mountains around us. Cold but not like where you are. At least I can ride here. Almost over.
Steve

"Valvoline Premium Conventional 10W-40." On sale at Autozone. I don't see an Energy Conserving Seal. I'll be in town tomorrow, so I'll shop around for JASO-MA compliant oil. And a new filter.

I don't think it's going to hurt anything. Valvoline Prem Conventional Product Info
I would change it after a few hundred miles or at the least 100 miles.
If a new filter was installed w the Valvoline, you may not need to replace it for the new oil.

Shell Rotella-T 15W-40 regular in the white bottle has the JASO-MA rating.
Chevron Delo & Valvoline Premium Blue are a couple of other heavy duty oils marketed for diesel engine use that should be about the same as the Rotella. Shell didn't change their oil to get the rating, they just had the tests done, probably for marketing purposes.

You can use the valvoline if you want. Better off with MA rated oil, but back before MA was ever even thought of, most everyone used regular car oil. Nowhere in any of my KZ owners manuals do they say to use MA oil, just 10W40.

Thanks martin_csr, I'll look for the Rotella 15W tomorrow. I already drained the Valvoline, so I'll make a fresh start with new oil.
Thanks for the pics, Steve. I'll keep them in mind while I'm shoveling my deck this afternoon.

One caveat about the Rotella is that it may not be suitable for cold climates for cold starts. Once warmed up, it should be fine. But you may want to consider a 10W-40 motorcycle oil.

Supposedly, motor oils have changed since the 70s & 80s. Back in the day all car oils had the ZDDP anti-wear stuff, but nowadays it has been removed or reduced to protect automotive catalytic converters. Heavy duty oils, racing oils & motorcycle oils usually still have the zinc-phosphate stuff.