yz400f problems?

7 replies to this topic
  • TheViper

Posted July 10, 2002 - 03:40 PM


i want to get a yz400f. i don't have much money so i will have to get a 98. are there any probs i should look out for on the 98s?

  • Guest_blatham489_*

Posted July 10, 2002 - 04:09 PM


You'll probably get a long list of replies. I just bought a '98 myself for the same reasons. My steal of a deal is now just a fair deal after several hundreds in repairs. The problems common to all years are cracked gas tanks(near the seat attach point), overheating when going too slow, sticky valves that turn in to bent ones (mine), poor lubrication of the swingarm and rear suspension points, frequent oil changes and the '98 had water pump shafts and seal problems (mine also). All of these and their common fixes can be found by searching this site. These are the ones I am aware of. Others can probably tell you more.

Any bike this high strung will have problems. Overall, I think I am going to be happy but I am still in the throes of the shakedown phase on a bike that had been apparently badly neglected.

Main piece of advice, have the biked checked thoroughly by someone who thoroughly understands the YZ-F series, and that probably WON'T be the local dealer. I am sure you can get plenty of suggestions from users on here if you say what part of the country you live in.

  • strack

Posted July 10, 2002 - 04:32 PM


blatham489 is right about the cracked tank on the 98's. I have one and got it for the same reason as you, the only problems i have had in a year of hard riding is: 1 cracked tank, one leaking o-ring seal, and one valve adjustment, overall i dont think this is too bad. I have a friend with a 99 wr400 and he has had only a cracked tank, but that seems to be commen with these bikes, especially the newer models.With regular maintnace you should have no problems with this bike.


98 yz400

  • Thumpster

Posted July 10, 2002 - 06:34 PM


I can't speak for the other '98s out there. I bought mine to get back into riding and did not want to plunk down a lot of cash on a brand new machine. The only problem I've had is a leaky seal in the waterpump, easy fix. The bike snorts, flat out rips and starts within 2 kicks. The previous owner had the jetting dialed in spot on. I highly recommend that you disassemble the swingarm and shock linkage bearings, lube them well and reassemble.

Keep the oil changed, clean the air filter and check the valve adjustment that's about it, for me anyway. However, I just trail ride so I won't speak for the maintenance required with racing.

Like anything used you always take a certain amount of risk. These things were designed to be raced/thrashed so there is going to be wear and tear. I'm sure you'll find a nice '98 or '99 out there that has plenty of life left in it. Take a knowledgable friend with you for a second opinion when you look at a bike.

As for me I decided my '98 was a good purchase, but I'll upgrade next season.

Good luck. :)

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  • m2g4b

Posted July 11, 2002 - 03:05 AM


Hey there, I also have a '98 model and I would definately buy another one if I needed it!!!! I bought mine 3 yrs ago, from the original owner, it was well taken care of...since then, and some will not believe this, but I have had not one problem with this bike...my gas tank is perfect, my valves have never went out of adjustment, and I checked them again just two days ago, the compression is perfect, and it is on the original piston...all I have done to this bike is put a chain and sprocket set on it and some new tires, and plastic...I love the bike, I rode it in the trails for the first two years of owning it and now I am in the MX world, since late last yr...the bike it holding up great...just my thought on the 1998 YZF model...thanks

  • YZeezee

Posted July 11, 2002 - 03:29 AM


Got to agree with m2g4b...I got my 98 about 4 months ago, so far it has run flawlessly...Started riding on trails, been to elevations over 11,000 ft, now I'm taking to the mx track. It's my first bike ever, and really has no problems to speak of. I had to redo the fork seals, and that's it so far. Valves are w/in spec, starts on the second kick every time, and pulls strong through all the gears. I love my 98, I'll look to upgrade in a year or two...

  • TheViper

Posted July 11, 2002 - 05:30 AM


how are the newer 426s and how do you think the 450s will be? i might be able to talk my dad into getting me a new one when i get some other stuff finished and sell some things.

  • sirthumpalot

Posted July 11, 2002 - 12:06 PM


The 426's are similar to the 400's but a bit more polished. Some minor bugs have been worked out (search the threads here for common problems). Basically the newer the better. As with anything used the person that you buy it from can be more important than the year of the bike. What I mean is, assuming similar mileage, a really well cared for '98 will probably have less potential for problems than a neglected or mistreated newer year.

If you can get the 450 then go for it! Just be sure to tell us how it runs. :)

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