my dad has a katana, and the engine has conked out. he thinks it may be the spark plug but doesnt no where this is on the bike. can anyone help???many thanks xx

have a ook on top of the head ( the top of engine ), yuo should see what looks like a rubber hose going to the head, there is a big rubber bit on the end, just pull that off & the plug will be under it, that is the lead,. it runs from the coil to the plug, DONT, touch it when the engine is turning over or started, u will get a nasty electric shock, CD l ignition systems put out something like 30000 volts, when u take the plug out, there is a number with letters on the ceramic bit, thats the grade of plug u need, also check the condition of the plug, if it is clean thats good, black could be a couple of problems, fuel dirty, timing out etc, if the little hook part is burnt off, it is stuffed, u should change the plugs whenever u do an oil & filter change

You should have 4 spark plugs located under the gas tank & air box. You will want to drain the gas tank then remove the tank/air box to gain access. You will need a long handled socket set to get the plugs out. It sounds like ur dad has neglected the maintenance if the engine is not working that likely requires or should involve more then a spark plug change. He should also get a new air filter & clean the carburetors while in there. An oil change & radiator flush should also be done at this time.