04 yfz what to watch for

[skyeryder]

I might be trading for an 04 YFZ what kinda problems did this year have or what are the plus's and minus's. Any help is appreciated I've always owned red so know nothing about the blue group, thanks

[Ride1Rob]

Find out everthing that has been done to the motor in terms of upgrades and such. You may not have to worry about anything if that's the case.

[dirtmomma]

We've had to replace our ignition coil a couple times & the batteries don't last, I think there was some kind of issue w/ them?? But other than that we've had AWESOME luck w/ ours :D:D
My son has raced it HARD for a few years flattracking & the only mods on it are the timing mod & exhaust!!

[jshtex]

Here are a few things....

Decompression plug in the head (above the exhaust pipe) will blow out. You can replace it with an aftermarket one that attaches better.

The swingarm will crack in an X shape on the top just above the rear shock linkage mount.

Some of them have some electrical issues. We have replaced the stator and the regulator / rectifier and we upgraded to a larger battery with more cranking amps.

Don't get me wrong here, one of my 04's has won a ton of races covering three years of HARD XC racing. My boy is racing a Honda now (got a great deal on it...) but the YFZ is still faster to this day. You just can't do what we do to them forever, and she deserves a restfull retirement.

[dirtmomma]

Hey jshtex what kind/part # of battery did you guys upgrade too? Just curious we replaced ours for the 3rd time for ONE race last Sept. & it is now toast again :( :ermm: It did set for awhile but our 426ex sits for months @ a time & has no issues :)

[jshtex]

Originally posted by dirtmomma
Hey jshtex what kind/part # of battery did you guys upgrade too? Just curious we replaced ours for the 3rd time for ONE race last Sept. & it is now toast again :( :ermm: It did set for awhile but our 426ex sits for months @ a time & has no issues :)

Dirtmomma, it is the YUASA YTZ10S. It is a larger battery and requires you to cut out the little pocket on the rear plastic that holds the tool pouch. But once you do that it looks like it was ment to be there. And it is like three times the CCA (Cold Cranking Amps) of the stocker. You used to be able to get them from Rocky Mountain ATV, they may also have them at C&D (site sponsor).

Here is a link to another site with some pics of an install.

Click Me! (http://www.yfzcentral.com/invision/index.php?showtopic=82127&hl=ytz10s)

I didn't have to do anything weird with the cables like he describes, mine just bolted right up.

But... honestly if your quad is killing batteries you may have something other than just real bad luck with batteries. The way I found out ours had other issues was we installed some high dollar lights for a 6 hour night race we were planning to run (we ran with the lights removed normally) and within a few seconds of running we blew out both bulbs.:eek:

At that point I tested the AC (yes it is AC) at the connectors for the bulbs and found that it was going to well over 30v AC. The regulator should keep it around 15v or less even with the engine reved up. So like I said above we replaced the stator and the regulator at the same time.

Do you run with the lights on, on your quad?

[dirtmomma]

Thanks :) the only time we run w/ lights is maybe once a year @ the dunes but other than that we don't for racing, seems that I was told it was better to run the lights as this charges something????? I could be confused though :o I'll go check out your pics sounds like something we should try doing, IF he ever gets back into racing that is :( he's just too busy, turned 18 is working 2 jobs & going to Tech school!!

[jshtex]

Originally posted by dirtmomma
Thanks :) the only time we run w/ lights is maybe once a year @ the dunes but other than that we don't for racing, seems that I was told it was better to run the lights as this charges something????? I could be confused though :o I'll go check out your pics sounds like something we should try doing, IF he ever gets back into racing that is :( he's just too busy, turned 18 is working 2 jobs & going to Tech school!!

On the 04's and 05's running the lights keeps keeps the bike charging at the full rate all the time. When the lights are off it drops the voltage available for charging some and then when the fan runs a lot, like during a race, it will actually cause the battery to discharge more than it charges. We ran a 6 hour race once and at had a dead battery before the thing ended...

We also run our lights because our bike actually runs better with them on. You can hear it miss at higher rpm's when they are turned off.

Yamaha makes a resistor kit for the 04 quads that basically tricks them into thinking the lights are connected and turned on all the time. It was only like $50 or something. The 06 and newer quads have this built into the electrical system.

I understand the busy kid business. My son is still "trying" to race but he is a Junior in College majoring in Mechanical Enginering. So he stays pretty busy as well.

Good luck. :)

[bsjoe]

Yeah, I'm trying to do mechanical engineering also.

What voltage should I be looking at if its charging the battery well (while running)? Cars are like 14.4 volts for example. I hit a branch once doing XC riding and had it go through my head light and through my plastics, so I just never replaced my head lights.

My battery keeps going dead, but I'm pretty sure its from mostly sitting and doing nothing.

[csr250r]

decompression plug, you need to get the oil mod or drills some holes so your wrist pin can get oil on it