What kind of hours are you guys getting out of a head on a bike used for trail riding that never hits redline and is used about 3 hours per ride?

As long as you take care of the air filter, cooling system and lubrication system there is no reason you shouldn't get at least a 100 hours out of it. If there is no catastrophic valve failure usually the first thing to go is the coating on the valves and that is why you would need to shim them. Some guys shim them once and once they need shimming again they replace the valves and springs and have the seats re-cut or replaced. Some guys have mentioned they have had hundreds of hours on their head before replacing valves.

270 hours and havnt even adjusted a valve yet let alone replaced piston

barns19, on 26 July 2012 - 12:16 AM, said:

WOW!!!!! Thats what I'm talkin bout! Maintenance is key!!!!!!

I race HS and usually always ride a fast pace when ever trail riding but I never ride the rev limiter. I am very thorough on my maintenance in that I change the air filter every race(or ride), the oil every 3-7 hrs depending on how hard it was ridden in that time and the oil filter every other oil change. If it was really wet or dusty, the oil and the air filters get changed sooner.

My 07 YZ250f has never performed anyway but flawlessly. I ran my original piston and valves for 150 hours. At that point I went to a CW 270cc cylinder, Vertex piston, had it ported and put in a new set of oem valves and springs. I ran that 270cc kits Vertex piston for 150 hrs and swapped in another back in like April but left the valves alone this time. They now have right at 200 hrs on them and only one has need shimmed, the center intake, and it hasn't moved since...and that was like 100 hrs ago. By this winter I expect the bike to have around 400 total hours on it and I plan to put in another set of oem valves, another 270 piston and rebuild the bottom end for first the time.

I usually get about 150 hours when the valves have been shimmed to their max.  I only ride off road I know that I am not sucking in any dirt through my air filter, I run filters on my vent lines too.  It is my exsperence that if the engine runs hot then valve wear is excelrated( running slow laying out a enduro or putting up arrows).  On the current 2009 I am riding now I installed Dell West intake valves, i have 140 hours on them and have not had to adjust them, they are the best investment I have made to the moto, well worth the extra cost.  I still check the valves every 30 hours.  This bike has a total of over 300 hours with two piston changes.

Awesome guys, thanks for the input!

My 07 has 87 million hours and has never needed a valve adjustment.

Lots of oil changes and clean air filters.

beezer, on 27 July 2012 - 05:28 AM, said:

hmmm that is a very exact number of hours

Quad rider.

beezer, on 28 July 2012 - 06:33 AM, said:

Yeah i ride quads and dirt bikes