My cooling fan is not coming on , I ride a 1999 zx9r .

check the fuel tap & filter that it is not clogged with debris from the tank & the breather pipe

The KTM sx is a full race bike - the radiators do not have fans to keep the bike cool when not moving - the bike must be moving to keep the air passing through the radiators to keep the engine cool - if you have the bike standing still there is no air moving through the radiator - hence why it over heats - tip start the bike after you are fully kitted up for your ride - let it warm up for around a min tops then ride - if you have to stop for a period of time when riding turn the bike off - I have the same issues of over heating if not moving on my VOR 530 - I do as described above and have no issues at all with over heating when riding. good luck

make sure that the thermostat is working and opening to let the flow of water in the engine, if it's ok you should start it and let it warm up and see if the cooling fan starts when temperature reaches close to 98 degrees, is it doesn't and the coolant boils then you have to change the temperature sensor as it is faulty.

Replace the clutch cut out switch on clutch lever

Bad ground.

Drain fuel Remove lines replace if needed Remove bolts to pump with out braking Clean around where gasket goes Check for dirt particles Install new pump Hook up lines and get riding again

Go here and download a shop manual. It's the first thing I do before I work on any bike. Then I burn a copy of it on a CD and give it to the customer.http://www.tradebit.com/G/manuals/9-motorcycle

what kind of bike are we working on?? the avg temp for the elec fan to turn onis around the 220 mark. the best thing to do here is bench test the bike start it up and let it idle, put a fan that moves air in front of the bike, this will help to keep things cool while the bike heats up i know it kinda back-@ssward but do it. a inferred temp gun will help you get the temp, you can pick one up at your local auto parts store. check the temp near the senser for the fan and the radiator itself. keeping a GOOD oil, clean oil in your bike that will help with the cooling as well. If your running a bike with a fuel filter ( If your not GET ONE ) make sure its clean. Bikes with fuel pump, you a two types in tank and external, your in tanks pumps should have a filter on them in the tank, over time they get clogged like a inline filter and can cause poor running as well.
If everything is working as it should you'll need to look into your coils. Heat causes resistance, resistance causes heat and heat causes wires to break down and contact points to to weaken. Coils take alot of abuse when it comes to electricity, it doesn't always happen but it does. coils go out and tire wear odd sometimes.
I hope this helps you out if you need any more help please feel free to contact me
Fix it right Ride it FAST
M.Woodring

you either have a severe missfire or its running too rich if it iworse when riding the bike and you do a rapid gear change to a lower gear and it pops and bangs a lot its air being sucked into the exhaust system from a leak in the exhaust joint or gasket failure check for blows around the exhaust clollectors or splits around the bracket that holds the pipe on to the bike frame

Hi! well I need more info like over heating around town? riding in the country? how's the water level? what condition is the engine in? radaitor condition
I think it is water cooled and some times the fan on the bike does'ent come on so when it's over heating
is the fan on? if not then thats broble the problem. on water cooled bike's I have installed a on off switch for around town and it helps keep them cooler.
MR NORM