CRF250. Is it rebuild time?

[Hazza]

Have any of you out there rebuilt a CRF at home?

I am thinking its about time to do mine, I have done a 100 hrs on it now with out a rebuild. Many people have told me that these bikes need to rebuilt every 40hrs or so i don't understand why if you maintain them regularly. Mine still has good compression and goes hard.

Is it worth doing it now?

What parts generally need to be replaced? Would i get away with using the same piston with some new rings and then freshen up the top end or is it worth going all out new piston, rings, gaskets, cam chain and valves etc?

What do you all recommend?

[7mmWSM]

Depends on the riding you're doing... MX you do sooner, trail riding you can leave them a bit longer.
Generally a 450 will go longer than a 250 as its working less harder.
Even for MX, I wouldn't bother touching a 250 til 60hrs and 450 at around 80 hrs for club level racing. The key is regular oil changes and air cleaners being changed as often as possible.

I would be doing it now as you don't know when that valve is going to drop or if the piston is going to stay in one peice, so do it sooner rather than later when something happen.

Yes do piston, rings, gudgen pin, clips, head and base gaskets. Cam chain should be ok unless it is noticeably noisy and check tensioner to make sure it operates properly. - its a lot of work to do just rings and worth it to do the piston since its apart.

Dont forget valve clearances - if they are out of spec this will cause hard starting and poor compression.

[Motoxparts]

We doing a rebuild on the 4 strokes it pays to replace the complete valve train valve springs are the highest weariug item in the mx 4 stroke engine we have stainless steel valve/spring kits alot better than the stock poor made parts and at a better price

gaskets pistons etc

www.motoxparts.co.nz or 06 8749495