Changing coolant.

This is a fairly straight foward job to do,

1. Remove the bottom bolt off the water pump, have a container or basin ready as the coolant will come out here.
2. Remove the side panel above the water pump.
3. Take off the radiator cap and the coolant will pour out of the water pump.
4. Remove the reservoir (expansion tank) and clean out with water.
5. Flush the system with water.
6. Replace the bolt in the water pump and tighten to torque setting 10nm.
7. Fill the radiator to the top and replace the radiator cap.
8. Fill the reservoir to the max level mark.
9. Start the engine and let it idle for a few minutes, then check the radiator and reservoir level, top up if neccessary.
10. Re-do step 9.
11. Install the side panel again.

Quad not starting or starting and then knocking off.

This might sound like a big problem but can quite often be the engine stop switch getting worn, damaged or weathered. Theres 2 philips screws on the bottom of it, when you unscrew them it comes apart in two pieces, behind the red switch theres a spring, as a temporary measure i pushed tinfoil in behind it with a needle to push the contact point out more, but long term this will have to be replaced.

Changing oil

When doing this job it would be a good idea to put in a magnetic sump bolt as it will gather up unwanted particles of metal that occur with engine wear.
1.Warm the quad for a few minutes.
2.Take off the plastic guard on the under side of the quad.
3.Use a oil pan or basin to collect the oil.
4.Remove the oil filler cap on the engine and the oil drain bolt which will be under the gear shift pedal facing out.
5.Remove the oil dip stick out of the oil tank and the oil drain bolt which will be facing down.
6.Remove the three bolts on the oil filter cover and remove cover and filter.
7.Check all 4 o-rings for damage.
8.Fit new filter and replace the oil filter cover making sure not to pinch any of the o-rings.
9.Replace and tighten bolts to torque setting 10nm.
10.Replace oil tank drain bolt and tighten to torque 19nm.
11.Replace engine oil drain bolt and tighten to torque 20nm.
12.Fill the oil tank with 1.55litres of oil and the engine crankcase with .30litres (total 1.85 litres).
13.Tighten the dipstick and oil filler cap and start up quad.
14.Check for leaks, If there is oil leaking re-check torque settings, o-rings could be pinched (this will mean draining the oil again).
15.Then put on the plastic guard and tighten bolts to torque setting 7nm.

Checking oil level

When checking the oil level, have the quad on a level surface, warm the quad up for a few minutes on idle, wipe dipstick and put into tank without screwing it in, remove again and check. Minimum to maximum level is shown with mesh design, top up if neccessary.

Leaking coolant

This is very common on the yfz. You'll notice coolant coming out of a little pipe on the bottom of the water pump. As long as you have noticed its leaking before its ran dry its ok, as its usually a seal that has perished or the shaft has wear on it and is damaging the seals. Yamaha have upgraded the seals in later year models and these seals fit earlier models. Here is a link to get part numbers for the parts you will need:

 http://shop.thumpertalk.com/oem.asp?partcategory=284219&manufacturer=6&category=1&year=2005&model=6888

I replaced the two seals 6+7, shaft 3, bearing 8, and all gaskets and o rings.
I didnt order the parts through thumper talk i just took down all part no's and ordered through a local motocross shop which were a lot quicker to deal with than yamaha dealers, All parts were oem yamaha.

YAMAHA YFZ 450 no compromise full on race action.

This blog is only a guideline, no liabilaty accepted due to damage or otherwise.