2004 yfz450 owners!!!

[Crazy lil punk]

hey guys, I am looking to buy an 04 yfz450 off some guy for 3250 obo. I just have some questions...

1) have you rebuilt your motor yet?
--If you have what did you do and why?
2) What is your maintnace schedual?
--oil changes, do you do pistons/rings? etc
3)What should I look out for?

thanks alot!!

[Trx4Life]

um
1) yes, use it mostly for drag racing. ran it about a year with just bolt ons, then added 13 to 1 piston and cames, ran it for about another year. Decided to put a big bore kit, port and polish, and set up for methonal. reasymbled and snapped the rod. curentely waiting on stroker crank.

2) I usually change the oil and filter every 2 or 3 trips to the dunes, it gets ran pertty hard so... um except for when i changed the piston i never messed with the rings.

3) I cant think of any thing that i really had problems with on this bike, been running the hell out of it since day one and except for the rod after last rebuild I have never had any problems with it.

I really like the bike, all ive ridden to compare it to is a predator, 400ex, raptor 660, banshee, 450r, and it is hands down my favoret out the bunch. Ive sold my pred and am looking into getting an 08 for my self.
Oh and if you need some paddles for it let me know i have a set of 7 paddle 22" extreem haulers. They are perfect for the yfz if it isent extended, but start to loose traction after you strech it.

good luck

[TRX450RACER174]

I don't own it but i do the maintenance on it for my teammate,
Motor has not been touched except for a 13.5/1 drop in piston,
no cams or anything else.
Oil changed after every race, no rings except for when piston was done.
Has been a trouble free bike for him never let him down in a race just some jetting issues with the setup but thats it.

[Crazy lil punk]

thanks guys.


Do I have to change the piston, etc, or can I just leave the motor alone and it will be okay?

[Trx4Life]

the only reason to change stuff is if you want it faster, if it runs and dont smoke, change the oil and give it hell.

I know a yfz with bolt ons (pipe filter jetwork) will usually easly out run a built 440 ex. I know on my old ladys bike with the pison and cams the only ones i couldent beat were spraying nitrous.

[Crazy lil punk]

okay cool

[420yfz]

1. several times, same thing each time. piston will let go, tear up the cylinder, bend or snap the rod and bend all the valves.

2. oil/filter change every day of riding, 2 timing chains and 2 pistons per race season.

3. watch out for broken motor mounts and the stock rear swinger on the 04 is garbage.

[Ride1Rob]

First off, if you do buy it. First you need to pull the top end of the motor off and inspect the play in your rod. If it moves side to side a bit sloppy or moves up and down the least bit when you tug on it your crank bearings will need to be replaced. Also, I'd do the oil mod b/c the wristpen on these bikes don't get enough lubrication and they could snap at anytime causing your rod to turn as a weapon against your bottom end (I've witnessed this). If the motor hasn't been rebuilt yet being that it's an 04 you surely want to get this done (That may only consist of piston/wrings/pen) depending on the condition of your crank and rod.

To the guy saying the only reason to this is to make it faster and to simply "Change the oil and give it hell." DON'T LISTEN TO HIM! This bike (because of the lack of oil lubrication to the top end) needs to be inspected if these upgrades have not been done. Someone trying to sell you a bike will not tell you if they haven't been keeping the maintnance up on it or if the motor was neglected. You could buy the bike and ride it for a couple of days, weeks, or months and then all hell brakes loose inside of the motor. CHECK IT!

[Trx4Life]

yea Ride1Rob does make some good points your are looking at a used bike it wouldnt hurt to check a lot of this stuff out. I know how my bike has been maintained and ive been through the motor a few times doing up grades.

Looking at ride1robs mods he seems like a motocrosser and you will see a lot more ware and tare motocrossing that regular trail riding. If you know for sure if this bike was motocrossed you should most defitnelly go through it. Otherwise you shouldnt have any major problems, find someone that knows about bikes to bring with you and let them look it over. Every bike is basicy a ticking time bomb I had 20 minets on mine after the last rebuild and the crank and barrings were all good and it still broke a rod.

Then I say if you have to worry this much about buying a used bike go get you a new one you will pay about the same note, it will just be a little longer. Plus you will end up with a much better bike considering all the factory up grades since the 04 has come out. Either way you shouldent be dissapointed.

[Ride1Rob]

Originally posted by Trx4Life
Every bike is basicy a ticking time bomb I had 20 minets on mine after the last rebuild and the crank and barrings were all good and it still broke a rod.

Then I say if you have to worry this much about buying a used bike go get you a new one you will pay about the same note, it will just be a little longer. Plus you will end up with a much better bike considering all the factory up grades since the 04 has come out. Either way you shouldent be dissapointed.

Trx4life, it probably broke that rod b/c of the insufficient oil getting onto the wristpen. That's why the 07's have an oil squirter that shoots oil directly underneath the piston to help resolve this problem. Yamaha knew about the problem wayyy back but would never own up to it. The advice you gave him on getting a new bike is the best advice yet ;) . You can't go wrong with a new bike and you have a warranty. I can't see why if you have $3500 you could put $1500 - $2000 down and use another $1000 or so in suspension setup. When I purchased my bike back in February of 04 this is similar to what I did and my payments were only $65 per month on the Yamaha plan.

[Trx4Life]

actually the wrist pin was fine the rod broke just above where it connects to the crank. what was left of the rod chopped the counter balancer in two, broke off part of the sleeve and took out a few parts of the inner cases.

Ive never had wrist pin problems. I know motocrosses have seen it from being run so hard for extended periods of time ( races). I'm more of a drag racer so the under lubricated pin has plenty of time to cool between races.

[dr.dyfz]

j and t atv makes a great oil pump its the 07's but they use ur case, its $220 and yamahas is $400 i did it and luv it

[Crazy lil punk]

Originally posted by Ride1Rob
First off, if you do buy it. First you need to pull the top end of the motor off and inspect the play in your rod. If it moves side to side a bit sloppy or moves up and down the least bit when you tug on it your crank bearings will need to be replaced. Also, I'd do the oil mod b/c the wristpen on these bikes don't get enough lubrication and they could snap at anytime causing your rod to turn as a weapon against your bottom end (I've witnessed this). If the motor hasn't been rebuilt yet being that it's an 04 you surely want to get this done (That may only consist of piston/wrings/pen) depending on the condition of your crank and rod.

To the guy saying the only reason to this is to make it faster and to simply "Change the oil and give it hell." DON'T LISTEN TO HIM! This bike (because of the lack of oil lubrication to the top end) needs to be inspected if these upgrades have not been done. Someone trying to sell you a bike will not tell you if they haven't been keeping the maintnance up on it or if the motor was neglected. You could buy the bike and ride it for a couple of days, weeks, or months and then all hell brakes loose inside of the motor. CHECK IT!


wait wait wait, whats the point of a 4-stroke if it has to be rebuilt all the time? I thought that was the glory of 4-strokes over 2-strokes?

[Trx4Life]

Thats what I always thought too. I know in the athena cylinder kit they recomend you change the piston , not just the rings but piston too every 15 hours. I think most of that is ment for hard core motocrossers though. Like I said I know a bunch of guys that has never had problems. Checking it is still a good idea expecieally if it was raced, but I wouldnt imagin you would have to many problems. Like I said earlier if I thought I would have to go through all that I would just buy a new one.

[Crazy lil punk]

I cant afford a new one, nor do I want to do payments. This quad looks like it was used for trail riding. I plan on taking it to the track to ride every other weekend

[A A R O N]

Trx4Life---if Athena really recomends that you change the piston and rings every 15 hours, I'd suggest staying away from that kit, because that's total bull. You should be able to go way longer on a top end than that.

Crazy Lil Punk---If I were you, I'd stick with a stock cylinder and piston to keep reliability....it will be plenty fast. Depending on how much this '04 has been ridden, I wouldn't trust it if it's never been rebuilt. With a correctly built motor, a weekend track rider and or trail rider like yourself should be able to get AT LEAST a whole year on a piston/cylinder. Just change the oil after every ride, or every two rides if they were short.....clean and oil the filter after every ride, keep all the pivot points on the quad lubed up, be gentle on the motor right at first until it warms up, and you should be good to go.

If all else fails...buy mine. It's an 04 too, but the motor has the oil mod, Baldwin port job, 06 stock crank, and stock piston and cylinder to keep it reliable, yet fast as well. I could take a few bolt on things off and sell it for $3500......or $3700 as you see it....or if you still have your 400ex i would be interested in that plus cash...

http://i155.photobucket.com/albums/s314/trxaaron/IMG_2728.jpg
http://i155.photobucket.com/albums/s314/trxaaron/IMG_2730.jpg
http://i155.photobucket.com/albums/s314/trxaaron/IMG_2732.jpg
http://i155.photobucket.com/albums/s314/trxaaron/IMG_2733.jpg
http://i155.photobucket.com/albums/s314/trxaaron/IMG_2734.jpg

[Crazy lil punk]

Originally posted by A A R O N
Trx4Life---if Athena really recomends that you change the piston and rings every 15 hours, I'd suggest staying away from that kit, because that's total bull. You should be able to go way longer on a top end than that.

Crazy Lil Punk---If I were you, I'd stick with a stock cylinder and piston to keep reliability....it will be plenty fast. Depending on how much this '04 has been ridden, I wouldn't trust it if it's never been rebuilt. With a correctly built motor, a weekend track rider and or trail rider like yourself should be able to get AT LEAST a whole year on a piston/cylinder. Just change the oil after every ride, or every two rides if they were short.....clean and oil the filter after every ride, keep all the pivot points on the quad lubed up, be gentle on the motor right at first until it warms up, and you should be good to go.

If all else fails...buy mine. It's an 04 too, but the motor has the oil mod, Baldwin port job, 06 stock crank, and stock piston and cylinder to keep it reliable, yet fast as well. I could take a few bolt on things off and sell it for $3500......or $3700 as you see it....or if you still have your 400ex i would be interested in that plus cash...

http://i155.photobucket.com/albums/s314/trxaaron/IMG_2728.jpg
http://i155.photobucket.com/albums/s314/trxaaron/IMG_2730.jpg
http://i155.photobucket.com/albums/s314/trxaaron/IMG_2732.jpg
http://i155.photobucket.com/albums/s314/trxaaron/IMG_2733.jpg
http://i155.photobucket.com/albums/s314/trxaaron/IMG_2734.jpg

thanks for the info dude, I still have the 400, but I am pretty far away from ohio, and plus I plan on keeping the 400, so I dont think that would work out to well.

Also, if the quad has never had the motor touched, and it hasnt had the balls beat off it, dont you think it would still be perfectly running because its a factory motor?

[A A R O N]

It should be fine, but I wouldn't expect it to be in the best of shape even if it hasn't been ridden hard. It's better to be safe than sorry. I'd rather spend $500 doing the top end than $1500 after waiting til the crank blew to pieces....

[Crazy lil punk]

Originally posted by A A R O N
It should be fine, but I wouldn't expect it to be in the best of shape even if it hasn't been ridden hard. It's better to be safe than sorry. I'd rather spend $500 doing the top end than $1500 after waiting til the crank blew to pieces....

give me a quick run down on what should be replaced and how oftenr and how much it costs. thanks alot dude

[Ride1Rob]

Originally posted by A A R O N
It should be fine, but I wouldn't expect it to be in the best of shape even if it hasn't been ridden hard. It's better to be safe than sorry. I'd rather spend $500 doing the top end than $1500 after waiting til the crank blew to pieces....

What he said! And like I said before, you could get alot of time off of this motor, but being that it's an 04.... For you to pull the topend off and check it isn't that difficult unless you're not mechanically inlcined. If not, you'd probably want to do what is stated above and spend $500 and having someone to check it for you. And as far as reliability on 2 strokes compared to 4 strokes. 2's recommend rebuilding the top end every 6 months I think. You can get 2yrs easy on a 4 stroke that's not ragged on. (***This doesn't include hopped up race type motors***).I'll be checking mine and replacing what's needed about every 6months :ermm: . But I do my own work so it's saves me ALOT in the pocket :p