Honda-SOHC

Could be worse.... one of the drivers at work put unleaded in his truck. 50 litres of the stuff mixed with 50 litres of diesel.  The bill to drain, clean and flush.....£3000.

Had he run the thing any distance, then the fuel pump and injector seals suffer, and that would push the bill north of £10k. Luckily he realised what he had done and didn;t just sert off on his delivery run.

I did it with the VFR. I didn't even know until I pulled out from the forecourt onto the main road and it died. I pushed it the two miles home and drained 15ltrs of diesel into three jerry cans and gave them to my neighbour for his van. I had to replace the fuel filter in order to be able to start the bike.

Petrol floats in Diesel so it will probably soon soot up the plugs then start to misfire.
Anecdotal Story
It was a long time ago but an lovely Irishman (Keith Dunne) I worked with used to put diesel in his petrol car to save money as in the 1960's it was cheaper- he drove a Standard Vanguard - it would smoke like the clappers and eventually it seized up.

Haha! It happened to me once when working in an australian farm. I filled up a quad bike to the pump dedicated to diesel tractors, whistling to that beautiful morning coming up. It smoked a LOT and finally stall 2 minutes later, and I learnt a LOT of new cursing and swearing in english from the local mecanic!

He drained the whole thing and cleaned everything with gasoline, the bike started as new and I went back to work fairly ashamed 

Did it smoke a lot?    I nearly did that once but a sharp eyed attendant rescued me!