1979 KZ400

Talk to me as a regular bumb off the street who knows little to nothing about this please.I have two questions about my 1979 KZ400.....

1. What oil should i use? The cap said SAE 10W40. What would happen if I accidently put Royal Purple 10W40 but it did not say for "motorcycles"? Is this bad or the same? difference?

2. I have gas coming from my carb at the overflow tubes. What causes this? Fixes? its significant and whenever i park it.

Any help is appreciated!

Hi and welcome to KZR.

1. No royal people won't hurt anything. oils formulated for motorcycles need to have and additive called ZDDP for proper lubrication of the can and tappets. also they should not have the high efficiency friction modifiers used in many automotive oils, these can cause slipping in the clutch. But it's not going to ruin an engine if you use a standard oil.

2. float valves are leaking, a simple cleaning could fix it, but the tips of the float valves are rubber and they do break down over time. A simple job, if you have a shop manual. I highly recommend getting the correct kawasaki factory service manual.

Thanks for the help!