YZ 426 experts -- I need advice

This spring I bought a 2002 YZ426 at a good deal. I have repaired a number of things on the bike and now it runs really good, starts easily cold or hot and looks pretty good too. Unfortunately, I have not had the time to ride it very much this summer. Here is my question; should I keep it or try to sell it and buy a newer model WR450?

I bought the bike to ride in the woods, single track and possibly an "old mans" class enduro or two. Will the 426 suit my needs well for this? I am concerned about the reliability. Even though my bike runs really good, I think that it may be needing a piston and rings soon -- it seems to puff a little smoke from time to time, not much though. I do not mind replacing piston and rings, but what is the possibilty of if needing main bearings or rod bearings in the near future (it is an eight year old race bike that I know little about) The first time I changed the oil in the bike, the oil was clean and there were positively no metal flecks in the filter or the oil line screen.

Also what about the cylinder head -- I removed the valve cover and it was surprisingly clean -- the cam chain and cam sprockets showed little wear and the valve clearance was at the tightest tolerance according the shop manual.

The motor is fairly quite for a four stroke -- about the same as my 06 DRZ400.

Will I have trouble with the 426 overheating on technical trails? Does anyone make an aftermarket coolant catch bottle for the YZ426? (I understand these are a good idea -- even though mine has never puked any coolant yet.)

Any recomendation on gearing for trail use -- the gearing on mine seems a little tall.

I like the power of the 426 and the way it rides; I am just concerned about what future repairs I might need; the bike overheating and reliablility for trail riding -- I hate having a bike give up 30 miles away from the truck.

So should I sell it or put a kickstand and a skidplate on it and go ride?


Take this for what its worth... back in 06 I traded my mint, low hour 00 426 that I had owned since it was new for a snowmobile for my wife and bought a new 06 YZ 450. To this day, I still wish I had that old 426 back and that I had found another way to pay for the sled.

The 426 is a great trail bike with just a little setup, and though it may not be as flashy or as light as the newer stuff it will still get the job done. Unless you are just dying for a newer bike or want the e-start feature, I'd say keep it.

The 426 is built to go fast on a MX track. The engine is snappy and responsive, but fussy at low speeds. First gear is tall, and the trans ratios are closely spaced. The suspension is stiff, and a bit unrefined.

A WR450 is built for woods and trails and has a milder engine with better low speed manners, softer suspension, a lower first gear and a wide ratio trans, and an electric start. It's also heavier than the 426 by about 12-15 pounds.

The YZ426 has a great reputation for reliability, if you check this web site you will verify this.

Regarding the coolant catch bottle, Motion Pro make one, or you can modify a WR450 catch bottle to suit, or you can use a Turkey Baster - there are a number of good ideas here on the site. The bottle is worth the effort. I ride hot desert and notice if I stop a lot without a wind down in speed (like you might in the woods, for whatever reason), the heat in the engine causes the coolant to overflow a little at each stop. Over time this means it gradually gets worse as the coolant volume drops. The catch bottle allows for the coolant overflow to be collected, and then drawn back into the radiator again once the engine has cooled (either from stopping for a while, or the bike is being ridden again).

Trailtech make a good kickstand for the YZ 426, at a much better price the Pro-Motion Billet.

You can also change the WR transmission straight into the YZ, you will probably be able to find a transmission on ebay OK.

Thanks for the input. I believe I will keep it for a while.


I raced my 2000 yz426 in a hare scramble last year. It's a heavier bike for sure ,handles a little slower too. It has been very reliable........I'm the original owner. :foul:

I geared down by adding 3 teeth on the rear spocket for offroad.

This worked very well, a skid plate is a must too. The biggest improvement you can do is to dial the jetting in........easier starting, better throttle response.

If you ride a friends newer machine........you will want to sell it.......trust me on that.:D

Other then that , Ride the blue bike and enjoy it.:bonk: I still have mine.

love my 426!!!

You won't regret keeping the 426. I have had mine since May 2002, new, and love it still. I run 15/51 on MX and have a 14/48 for woods and desert. Enjoy the ride and best of luck.


You won't regret keeping the 426. I have had mine since May 2002, new, and love it still. I run 15/51 on MX and have a 14/48 for woods and desert. Enjoy the ride and best of luck.


If I were you I would swap the counter shaft sprockets.

15/51 has a ratio of 3.40

14/49 which is stock is 3.50

14/48 is almost 3.43

14/51 which is what I run at the track is 3.64 and the bike feels like a monster.

15/48 would be a ratio of 3.20 which would give you a lot more top end at the desert and just ride a gear lower in the woods. So your two ratios are only, three hundredths off which you probably cant even notice and you're taking all the parts off and putting different ones back of for a very minor difference.

Just my 2 cents.


I am the second owner of my bike, the previous owner was a mechanic at the dealership we bought it from. I love my 426, sure I would also love a 2011 450 but that isn't going to happen. All I can recommend is stay on top of the maintenance like checking and changing the oil regularly, make sure the valves are in spec which you have already done, clean air filter and keep the carb clean. Pretty much if you just take care of the required basics the bike will take care of you. Mine starts first kick 99% of the time and runs great. It has never left me stranded anywhere and Ive gone on 50+ mile rides. Maybe gear it down a little bit if you think its a little too tall, the best way to figure it out is buy a couple sprockets and try them out for yourself. Just get the suspension dialed in, take care of the motor, and if you're the type of guy that can work on it yourself, do it. Paying for the parts isnt bad, its the labor.

Edited by c_dasilva127

Gsev, I bought my 02 426 in a box last year, and thanks to the helpful souls(Grayracer et al) on this site I got it together last fall and have been beating it like a red headed stepchild for a year now. I am 280 lbs and had not ridden dirt in 17 years when I started really getting back into it on this bike(we won't count the few horrifying rides on my Husky, thats just for lookin' at) After some spring work and a HUGE learning curve, I absolutely love this beast. Is it heavy? Yes, does it stall? Yes, Is it an absolute cow to start if you stall it? Yes, but if you are mindfull of your clutch, and you gear it right, you won't stall as much as you think, and I'm convinced that lovely four stroke power made me a better rider than I really am. I am now back into racing(Hare Scrambles) and I may take the plunge(tomorrow actually) to a 300 XC-w, mainly because of weight and that ginchy electric starter, but I think I'm gonna keep big blue just for that motor and the giggle it gives me while trailriding.

Have fun!


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