Just bought a 2000 426

Congrats on the buy! I love my 2000 yz426. Ditto on the starting procedure. Get it down before you go ride. Damn near blew out my knee kicking it over my first day. NO problems once I got on the forum & got the tips on starting. I am going to do the 450cam mod soon. IT's hard to argure once you've heard all the raves on this forum about it. Enjoy:ride:

I'm going to look at a 2002 426 here in California today. Really excited, but I do have a question for the experts. Assuming the bike hasn't been ridden that hard...when would you typically need to replace the top end? I see soooo many ads with 'new top ends', etc...just wondering why so many need to be replaced. I'm a bit hesitant with a used 4-stroke as it is quite a bit more expensive to do a top end on a 4-stroke as opposed to a 2-stroke.



That's a tough question to answer on a YZF. A lot of top ends have been "freshened up" because someone thought it would be a good idea, or because a shop sold them on it, but may not have been strictly necessary.

There is almost no way to predict how long they will actually last, although the rings in 426/450 YZF's often tire before the valves need work. I'm starting to set aside money for rings and valves on my '03, just because it's over 3 years old now, and it seems like it should need work sooner or later, but it doesn't yet. It's easier to judge if it's a bike you've had for a while and you can kind of see how things are going. With used stuff, it's very hard to tell. Looking at it's current condition and maintenance is about all you can do.

Lets see some pics.

I'll take some new pics soon, it's in pieces right now, The previous owner wasn't much into grease so the swingarm and linkage are getting new bearings. I put new plastic, graphics, lever's, grips, tire's, changed oil & filter, new throttle cable. I Plan on checking valve clearances too.

Here's a picture as purchased, I'll be working on getting the funky black and sliver powder coating off the frame and restoring it back to YZ blue


1979 rm125 006.jpg

The BK mod is the best mod i've done to my 426, and that's after I spent $600 on it. It cleaned up the bottom REAL nice, and I can wheelie with the utmost of control now. It took me an hour, and I already had the parts! (One screw and a little spring). The mod is detailed in the sticky at the top of the forum.

Can some one tell me, in detail, about the Woodruff key issue, and what to do about it? Thanks -Micah.

Part #18 on this diagram...


It's a very soft material and if left unchecked it could shear off causing all kinds of havoc. If you hear a knocking sound coming from the impeller area be sure to investigate the woodruff key. I changed mine earlier this year for piece of mind.... it cost a buck and took about an hour.


I failed to mention that it is the keystock to hold the counter balancer gear onto the crank. If you ever need a new crank update it to the 01/02 crank as Yamaha did away with the soft keystock.

Part #18 on this diagram...

Actually, it's number 9 on the other end of the crank.

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