[Widdy]

HI everyone,
CRF250R 2005 Stock

rebuilding by bike and as I bolted the engine back into the frame I thought i'd do a compression test, I understand the manual states it should be done warm and should be around 57 psi, but I've done it cold as its not yet ready to run. I got a reading of 25-30 psi whilst cold and i'm concerned the valve clearances are within tolerance. is the difference between warm and cold rearly 27psi? or have I got a bigger problem.

cheers

[JimDirt]

Need a bit more info on the "rebuild" , as your description is a little vague , were the valves done ?? , are you positive the timing is correct ?? , was the ring gap staggered and placed according to the manual ??? , did you check the compression using the procedure the manual said to do to check it ??

[Widdy]

Rebuild may not have been the right word, break down and clean is what I did, replacing worn parts.

Anywho I decided to pull the head and found a leaky valve which would explain the low compression (hot or cold) just debating now weather to have the SS seats recut and wether I should get 4 new valves or have these refaced.

[JimDirt]

If you are not racing seriously , then Stainless is the way to go , its 1/10th the maintenance and gives you peace of mind that the valves are not going to go out in a season like Titanium sometimes do , I have 13 years on one set of Stainless Intakes without a valve adjustment needed on my 06 450X , and another Intake set I did in 2016 (with springs) that is still exactly where it was when I first set the lash at assembly on my 02 450R

I track ride that bike every weekend from usually Feb. till October and have done so without needing a adjustment yet ... the week before last I track rode Thursday,Friday,Saturday and Sunday , then rode again this Sat/Sun , like I do most every weekend as long as the ground is free of snow , I enjoy the fact that all I need to worry about is freshening up my suspension once a season and keeping the oil changed every 6-10 rides (Synthetic) , and spend the rest of my time riding instead of replacing engine parts or adjusting valves

To somewhat directly answer your question , it is basically up to you and your budget , if you can afford to do a complete valve job then do it (Ken *the owner of this site* does excellent work and also offers complete heads set up and ready to install) .... if the Exhaust are still in spec , then just do the intakes , as Exhaust will outlast Intakes (Titanium) by several seasons usually ....... I have only done Intakes on both my bikes and have not had to adjust the Exhaust since I have had each bike (the 06X I got new in 05 , and the R I got in 08 , and have not needed to shim the Exhaust on either yet ..... Either way , you can't go wrong .... , and you do not "resurface" the valves , they are a "wear part" and are only replaced , you resurface the valve Seats by either recutting them or replacing the seats with new/better ones ......