[rhiocrf230]

I bought a bone stock used 2007 250R 13 months ago the bike still had original tires. The owner stated it had about 80 hours on it of mostly trails. I have close to 200 hours on the bike since then, mostly fire roads and trails. The valves were check recently and are still in spec. The bike starts in 1-2 kicks hot or cold and uses a little oil. When should I have this old dog rebuilt? should I do the top end only or the entire motor. I thought these engines had to be rebuild every 50 hours or so.... any thoughts.....

[JimDirt]

If your Justin Barcia , yea every 50 hours or less , if your a normal rider (especially a trail rider) then basically when you notice the valves going out of adjustment or when the compression seems less , i have a 06 450X that i have had since June 06 new , it is still on the original Piston,Rings,Clutch , that said , i never hit the rev limiter and usually lug it , i keep the air filter clean (i learned that the hard way after loosing the intake valves about 6 months after i got it,it now has Stainless Intakes and has not lost adjustment since the change in the 7 years i have had it) , but i am at 7 years and about 3500 miles and about 400-500 hours (did not have a hour meter until just recently) of off-road on the original piston if that says anything

Its kind of a crap shoot , you CAN change parts every 100 or 200 or 300 or 500 hours and be fine , its all about how you ride and how you take care of the bike , i change oil 2 times a year at most , BUT i use Synthetic not Petroleum oil , to me that makes all the difference in the world as far as change frequency

Some people will tell you that you must change everything every 20 hours , if you bounce it off the limiter and are riding at a A or Pro level , then yes , otherwise , i feel its a waste of good money that you could use on gas or something you really need or want ...but thats just me !

My 02 450R has been together since i got it in 08 and is just about ready for valves , so this winter i will tear it down and put in a fresh piston , timing chain and valves , this bike saw the track EVERY weekend for 2011 ,plus went trail riding almost every weekend , since 08 in between track rides , so its lasted pretty well and i can still get on it and start it within 1-3 kicks every time, in fact i have been at the track with it the last 3 weekends in a row , it was supposedly rebuilt by the prior owner just before i got it in spring of 08 , that was 5 years ago and a few hundred hours ago

Just be realistic about how you ride and maintain it , that will tell you when you need to go thru it , there is no , do it at this many hours or rides schedule , its all subject to many factors , though i personally would not go over 500 hours , i may do my X this winter or maybe next , i have not decided yet

[riddler9]

The only things I would add to Jim's post is

1)The piston skirt on the 250 is extremely small so a couple of hundred hours is a long time to go without checking it. Since checkign the skirt is only around $150 short of changing it, I would change it. At the same time, if you open it up and find the skirt still has plenty of meat then you have a good benchmark for your next piston.

2)CRF bottom ends are extremely durable. 400+ hours is by no means a stretch for a trail rider and at that, you typically just want to leave it unless you hear something going or the center gasket starts to leak.

3)You should change the decompression spring at least every 100 hours - cheap insurance

4)Within the first 50 hours after a rebuild (or new) and every 25 hours thereafter unless replaced, you should check and if warranted, replace the timing chain and sliders as well as the tensioner. Wear of these parts is easy to diagnose, they are easy to change, and they can cause lots of damage if they fail.