what all should i look for and service will i have my 04 engine apart

[quader400]

its time for a rebuild for my 04 450r engine. im going to take the whole thing apart see how its doing and replace all gaskets and small things, probably new piston, but what else should i look for? what else should i replace. thanks

I would put new crank bearings and a timing chain. Also a valve job and new valves.

[bloodmoney23]

yeah like trx450_racer said, and i would also change ALL the bearings in motor, valves, valve springs and retainers and since it is already apart do a aftermarket crank.

[rt20ps]

In addition to the items listed above I would recommend doing the clutch mod as well as some heavy duty clutch springs.

[Sjorge450R]

eh....i wouldnt change the clutch. The clutch is so easy to change on these motors that i wouldne even worry about it. If it grabbed when you took it aaprt, it will when it goes back together. Worse comes to worse, you can swap it out in like 10 min wiht a new one.

[ktmbill]

And the most important thing is the oil pump yes the oil pump and clean out the oil lines or replace

when i took my old springs out 4 were snaped in half so replace springs and clutches