2001 yz426

well I sold my xr600 for a 2001 yz426 for $1700 with a blown head gasket....so I am rebuilding the top end with a new cam chain, 450 exhaust cam, new valve springs, and possibly a new piston, (or maybe just rings depending on piston condition) and of course a new cometic gasket kit. What am I missing since it is pretty much apart right now what should I do?

A new Rod?

I would first determine if it overheated badly when the gasket blew. You may want to check the bottom end and also for scoring or any heat related problems that could cause a failure later. If you have it part might as well piut in a new piston insted of only rings. New crank and rod bearings would probably be a good idea. Also you may want to have the head checked to see if it warped at all. Alot of my suggestions are for worst case scenario but i would rather know my motor is sound.

You really won't know exactly what parts you need until it is opened up and you can assess the damage and take some measurements on play between parts and bearing condition. Odd on a piston kit and maybe the rod/rod bearing are needed. Check the valves carefully, too. Best of luck and keep us informed.


As long as you are replacing the valve springs, which is very wise and inexpensive, you should have a look at the valves.

These pictures may help you with that.

Measure the valve guides as well and replace as needed...also replace the seals (they're cheap, too)

well finished rebuild last night, did new valve springs, valves were great, new piston rings, 450 cam and cam chain, did my throttle cables (old ones were frayed pretty bad) a few other odds and ends. I love this bike the power is awsome and with the cam chain it stats as easy as my 600 did. when I finish my plastics, I'll post some pics, with the $1700 and $280 to do the rebuild I think I got a good deal out of it, the guy who sold it to me didnt want to mess with it so I got a decent price. It will now be very well cared for I cleaned the crap out of everything, the power beats my 600 (top end not really but the tade off is worth it) Anyway very please with the bike and looking forward to hitting the deserrt soon!!!!

I must say that I was in your EXACT position last year when I sold my 99 XR600 and picked up a 01 426. One of the best purchases of my life! I miss the couch cushion seat, but that is about the only thing I miss!! :applause: Congrats, you will find it is so much easier to ride through the desert. I think the only thing the XR did better, was wide open through the fire roads. It was dead solid. The draw back was that it was dead solid everywhere else too which made it a chore to move around! Have fun! You won't hardlyl miss the old XR! :applause:

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