Unless someone talks me out of it, I'm buying a '99 YZ400 today...

Found a near mint '99 YZ400..all stock except for renthal bars..low, low hours for $2300. Should I do it?

I just bought a 2000 426 for the same amount a couple of month's ago. If the bike is really clean, go for it. If not, hold out, 426's are in that price range.

Good Luck!


If the camchain hasnt been replaced in 5 years, buy a new one and stick it in. Mine jumped a few teeth causing the intake valves to hit the piston a few weeks ago. Fixed that. Then yesterday, it jumped teeth twice after retiming it. Luckly the valves didnt hit the piston. Ordering a new cam chain today. Other then that, tell your buds to buy some roost gaurds :thumbsup:

good choice :thumbsup:

Thanks for the input everyone. Yeah, I was looking for a 426, but I think the prices for used bikes in Boise are higher than other states..I can't get into a 426 that is in good shape for under $2800 or so. What did that cam chain set you back for the 400?

33 bucks.

The 400 owners are also lucky becuase valves only cost about 10 bucks each.

While your there I think the 450 cam chain tensioner works on the 400/426 engines. Its smaller and makes working on the carb easier. Good luck! I have a 99 YZ400F to many add ons to list but the Edelebrock carb, and the 450 cam mod are the best things I have put on my bike.

My tensioner is working as it should, but do I really have to replace it?

THe 400 is a great bike. It is a bit heavier than the new bikes. But if that dosn't bother you then go for it.

I have had mine since new and it is a geat bike. The carb is a little more finiky than the newer ones. The acelerator pump has a tendancy to get dirty.

As said a new cam chain is recomended. In order to install the chain the cylinder has to be removed. So you might as well install a new set of rings and reshim the valves while you are in there. By doing this you will know exactly were the motor is at.

The chain, rings, valve shims, and gaskets shouldn't set ya back more than $150 if you do the work yourself. You will also need a 1/4" torque wrench for the cam caps. Feeler guages for the valve clearances. And a flywheel puller to get the cam chain in.

Not to sound like an a$$ but I just did the 450 cam mod and replaced the chain while I was there and you dont have to remove the head to replace the chain. Its a little tight but it can be done very easy.

YZfan is correct, all you need to remove is the flywheel cover, flywheel, cam chain tensioner and cam cover. While your in there you might as well throw an extra 100 bucks at it and do the auto decompresser ('03 450) cam swap.

I got the bike. I'm stoked, that thing is awesome. Ok, so I'm going to dig into it and do these things you guys are talking about. I'm an beginner/intermediate level mechanic, and I've got a serious set of tools, would you guys recommend that I do the work myself, or should I have someone that knows whats going on do it? Of course, cost is an issue. Also, I didn't get an owner's manual, I assume I'll need to buy the repair/service manual from Yamaha?

Definately get a repair book from yamaha. See if you can find a used one cause yamaha charges 60 bucks for one. I would do all/most of the work yourself. Whatever you feel comfortable with. Ask questions on TT if you have to.

I JUST turned 15 a few days ago. i took off the head by myself and put new valves in. I do all the work on my bike except for putting the valves actually in the head and putting tires on. My dad does that for me.

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