Maintenance schedue, yz400f

4 replies to this topic
  • tek_01

Posted August 29, 2009 - 12:55 AM


Hello fellas my bro has purchased a 99 yz400f just recently and i was reading through the manual as he isnt too mechanically incline and noticed a few things

Piston and ring maintenance: it says replace the rings every 500km and piston every 1000km from memory

Valves: It says to check clearances every race

He rides the bike only on trails, never races but doesnt mind to give it a bit

So what im basically asking is how often should we really be doing the above mentioned things? and to my understanding you have to take the head cover off to check valve clearances so that means a new gasket every time?
TBH i think that is very excessive and probably only for racers that rebuild every race

Would i be able to say change the piston once a year (probably at a guess 70-100 hours per year) and check the valves every 3-6 months?

  • spc mike

Posted August 29, 2009 - 07:10 AM


well since its an older bike with an unkown amount of hours i would at least check the valves and replace the cam chain. A new piston would be ideal considering the age but that is mostly at your discretion since its not being raced. My bike is a 2002 YZ426F with the original piston and has excellent compression still.

As for the valve cover gasket to check the valves, you dont need to replace it because its rubber and self sealing without any silicon or stuff like that. However you could relace it for assurance if you are suspicious of any cracks or small tears in it (once again because its an older bike).

piston and cam chain every 2 years for what you ride.

check your valves every couple months or if you have accumilated alot of hours then check sooner.

....but thats just what i would do in that riding situation. I also change my oil (Amsoil) every 8 hrs of ride time.

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  • tek_01

Posted August 29, 2009 - 07:27 PM


That sounds more reasonable, does anyone else have any input? agree or disagree?

  • USED YZ426F

Posted August 30, 2009 - 05:25 PM


What he said. Replace the cam chain and check the valve clearances (adjust if necessary).

Change your oil every couple of rides and clean your air filter after every ride.

You should have a lot of good quality riding time on that beast.

  • tek_01

Posted September 01, 2009 - 04:00 AM


Pity its not my bike, its my brothers... im jelous and always thinking of buying an mx bike but my xr400 is road reg and i also use it for shooting so it suits my needs better... but i can always "want" cant i? :ride:

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