YFZ problems

[4TraxRider]

My stator just went bad right after I got it running from a cracked piston 2 weeks ago. I haven't had any luck with this thing at all. I've already had to buy a new tie rod, two ball joints, and send my carb back to the dealer to have it so it would even run above idle when it was new. I've only put about 10 hrs of trail riding on it and about 4 races. Does anybody else have a lot of problems with their first model run YFZ's? Might have to go back to Honda if this keeps up.

[nhyfzrider]

mine's been great to me, very solid machine. 11 months of pounding, not one problem.

[geogeorge]

I have a 04 and its been great to me. I've trail rided it twice and raced it three times and no problems yet. It could be you just got a lemon. Lots of guys race them in Missouri and for the most part little to no problems. Did have one guy that found out you have tohave your headlights on if you wish to charge your battery why running over 5000 rpm's . Other then that its been a great baike so far.

[Johnson]

One year old and still holding together every good frame, tran., and motor no problems. Race in the pro class XC.

[4TraxRider]

I must just have an oddball. I've taken absolute perfect care of it so far and am still having problems. It should be back early next week for another try at redeeming itself in my eyes. I just needed to vent a little bit. This is the first "brand new" quad I have every got and it's giving me tons of problems.:mad:

[Quad18star]

I had problems with my battery/electrical/stator . I went through 3 batteries and the shop told me the stator was screwed on it . I slapped a new battery ( under warrantee of course) and never ahd a problem since ..... so who knows what was wrong with it ... especially the mechanic telling em the stator was screwed .... and he's been a mechanic for like 20 years and he's the best in town :confused:

[daddio]

from a yamaha tsb

Unique Charging System Characteristics - Yfz450
The YFZ450 Charging System is designed to
supply at low to medium engine rpm a maximum
charging rate with the headlights in the
ON position. Under some conditions (e.g., low
speed with cooling fan running frequently or
continuous high rpm riding), it may be necessary
to ride with the headlights in the ON position
continuously to maintain a fully charged
battery.
If a customer complains of the battery discharging
while riding, first check the condition
of the battery.
NOTE: If improperly charged or boost charged,
these compact batteries could overheat and
become permanently damaged. To prevent
overheating, charge the battery using a low
output charger (e.g., Optimate III, ACCOPTIM-
AT-E3), and test the battery to make
sure it is in good condition. Next, Check the
output of the charging system.
To avoid mis-diagnosis, follow these procedures
and specifications in the order below:
1. Minimum key off (battery voltage must be
12.80 VDC).
• Voltage too low: recharge and load test
the battery.
2. Measure the battery voltage at idle. *It
should be 14.0 ~ 14.9 VDC before the cooling
fan starts to cycle ON and OFF.
• Voltage too low: check the stator coil
resistance. The correct specifications
are:
– Yellow to Ground = 0.22 ~ 0.60 ohms
– White to Ground = 0.29 ~ 0.84 ohms
– Out of Spec: replace stator assembly
• Voltage is too high: check wire continuity
(particularly the black wire which
should have continuity between the
Ground). The Yellow/Red wire should
have continuity between the lighting
coil and the regulator.
NOTE: If continuity checks good, replace the
regulator assembly. (Commonly, both headlights
are burned if the regulator has failed.)
• Voltage Okay:
–
–
–
NOTE: Do not check the battery voltage at
5000 rpm as explained in the Service Manual.
Charging output will decrease as rpm increases.
This is a normal characteristic of this
model.
*Since the system normally discharges anytime
the cooling fan is ON, all testing must be
done before the fan starts to cycle on and off.
Otherwise, the maximum measurable battery
voltage will be lower than 14.0 VDC.
SUBJECTS: 1. Unique Charging System Characteristics - YFZ450
2. Introducing YFZ450 Charging System Resistor Kit -
Resistor Kit for Competition Usage
3. YFZ450 Resistor Kit Installation Instructions

Check the radiator for blockage and
correct as required.
Advise the customer to use the key
switch to turn the engine off. Only
use the engine switch (on the handle
bar) in an emergency.
Advise the customer to switch the
headlights ON to increase the charging
output.
Introducing YFZ450 Charging System Resistor Kit -
Resistor Kit for Competition Usage
Symptom:
As explained in the previous subject (page 1),
the YFZ450 Charging System is designed to
supply at low to medium engine rpm a maximum
charging rate with the headlights
switched to the ON position. If the headlights
are removed for competition use, the unit may
experience battery discharging.
Remedy:
Install the YFZ450 Resistor Kit. The kit contains
a ceramic resistor which takes the place
of the headlights to maximize the charging
rate, plus it provides a higher temperature fan
thermoswitch to minimize current draw. The switch is
located sitting on the bike the upper right switch
NOTE: This higher temperature is still low
enough to not cause engine overheating.
The kit is optional for competition use and warranty
does not apply. The kit was developed to
allow maximum charging and reduce battery
load.

the part # is 5TG-REGST-KT-00 from your local yamaha dealer. s/b about $45

[nhyfzrider]

that was cool as hell.

[Sick0]

Owned now for 1 year.

Broke
a-arm
front shock
swingarm
sterring stem
chain guide
pipe
head pipe
plastice mount
tie rod
And the biggest disappiontment
All five gears went in the tranny in the first 3 months.

Besides the tranny going, this quad has been good to me.

[Quad18star]

Originally posted by Sick0
Owned now for 1 year.

Broke
a-arm
front shock
swingarm
sterring stem
chain guide
pipe
head pipe
plastice mount
tie rod
And the biggest disappiontment
All five gears went in the tranny in the first 3 months.

Besides the tranny going, this quad has been good to me. I think you got a quad made on a Friday at about 4:30 in the afternoon ... or one made on a Monday !!!! Thats some bad luck .

[CTmxyfz]

Owned year and a half:
Decompression plug blew out
Battery sucks and doesn't hold a charge for ****
Just rebuilt it

I love it besides the time you need to rebuild them and the battery doesn't hold a charge for crap.

[shep]

I have had 2 YFZs and 0 probs. for you guys that have battery probs, ihave replaced stater and rectifier in 2 of my buddies bikes, the early models had probs, YAMAHA has since fixed the problem to the best of my knoledge!

[BOONE450R]

no problems here.:p J/K

[daddio]

Originally posted by CTmxyfz
Owned year and a half:
Decompression plug blew out
Battery sucks and doesn't hold a charge for ****
Just rebuilt it

I love it besides the time you need to rebuild them and the battery doesn't hold a charge for crap.

Look at the above "racer update" post. that should fix your problem.
yamaha also sells a battery charger and special plug in to keep your battery fully charged.

I found one more thing this weekend....... a black wire in the main wire harness under the hood, had rubbed bare on the frame, and was shorting out and causing the quad to quit. I am goung to check all my wire routing on a regular basis now.

[I-7]

Originally posted by 4TraxRider
My stator just went bad right after I got it running from a cracked piston 2 weeks ago. I haven't had any luck with this thing at all. I've already had to buy a new tie rod, two ball joints, and send my carb back to the dealer to have it so it would even run above idle when it was new. I've only put about 10 hrs of trail riding on it and about 4 races. Does anybody else have a lot of problems with their first model run YFZ's? Might have to go back to Honda if this keeps up.

Damn tyler whats that now... 4, 5 quads in the last 2 years :eek: . Jk man.... good luck getting it fixed :(

[CTmxyfz]

Originally posted by daddio
Look at the above "racer update" post. that should fix your problem.
yamaha also sells a battery charger and special plug in to keep your battery fully charged.

I found one more thing this weekend....... a black wire in the main wire harness under the hood, had rubbed bare on the frame, and was shorting out and causing the quad to quit. I am goung to check all my wire routing on a regular basis now.

this is a race machine and yes, i know about the kit. I don't have any money though yet.:eek:

[SRH]

ive had mine for almost a year so far its been as reliable as my 400ex...i hope it stays that way

[tazdevil27]

Just visited (i'll say it quietly) bluetraxx.
Seems a few people are starting to lose motors with the pin pulling out of the piston. Yamaha dealer here couldn't tell us how long before rebuilds, maybe they are finding out now that 12 months is too long.

[daddio]

Originally posted by tazdevil27
Just visited (i'll say it quietly) bluetraxx.
Seems a few people are starting to lose motors with the pin pulling out of the piston. Yamaha dealer here couldn't tell us how long before rebuilds, maybe they are finding out now that 12 months is too long.

(very quietly) I visit bluetraxx quite often, as there is alot of info on yamaha's there. If you really read into these posts about reliability problems with the yfz, you will usually find that the problems have more to do with heavily modded motors, very hard riding, neglect, etc. or all of the above. as with any kind of hard riding/racing, on ANY vehicle, the more it's abused, the sooner things break. that's why Doug Gust get's a fresh motor EVERY race and sometimes between moto's. if you ride very hard, and modify your motor (ignition,pipe, high comp. piston, removing the fan, larger carb,etc.) you should pull the top end apart every 20 hr's or so, and change the oil at least every other race. if you casually ride a bone stock bike, and change the oil every 20hrs, you should go 200 hrs + before a rebuild.

[nhyfzrider]

my yfz is fairly stock w/ just the pipe/jet/cam mod and it is tough as hell. i make sure to change the oil/filter every 3 rides.(about 7-9 hours) 11 months and counting. getting ready to do a piston and rings.:)

[4TraxRider]

That's what's most agrivating about it, is that I take better care of it than any quad I have ever owned. I know a guy who's had his YFZ for a year or so already, and just changed the oil for the first time last week and has never had a problem other than his rear mastercylinder. I'm one step away form stripping it down every week as it is and I'm still having problems.

[allmixedup047]

a black wire in the main wire harness under the hood, had rubbed bare on the frame, and was shorting out and causing the quad to quit. I am goung to check all my wire routing on a regular basis now.
my buddy had this problem the last trip to the dunes, he didnt ride all weekend, it was grounding itself out.

[shep]

you should pull the top end apart every 20 hr's or so, and change the oil at least every other race. if you casually ride a bone stock bike, and change the oil every 20hrs, you should go 200 hrs + before a rebuild.


__________________
2002 blaster - a few mods - kind of fast
2004 yfz
sponsers
Enumclaw Suzuki, ODI grips, TCS Motorsports, Action cycles, DeVol engineering, American powder coating, and grandpa bill

I had my 04 for a hole gncc season, my shop tore it down, and every thing was in specs!!

[Jersey450R]

shoulda bought a HONDA!









to EVERYBODY

[Kennethyfz450]

I had two honda's before my yfz the first one leaked oil .. defect in the cylinder a few had honda knew about it so they covered it under warranty..

400ex bearing went out casued a lot of trouble!



yfz450 nothing besides i cant get the darn thing jetted right!

[daddio]

uh-oh.......here we go.......... blue vs. red :devil:

[sMoKiNyFz]

Originally posted by Jersey450R
shoulda bought a HONDA!









to EVERYBODY

Don't get it started

[larkspred]

My friend just got a yfz and it was runing for two days and now it wont start, even with a battery charger on it. it wont even crank over. the other thing it wont even push start if any one can help it would be alot of help thanx.

[allmixedup047]

all my buddies yfz's are always down for something. i just thought it was there hill billy motor skills. if you dont know what your doing, dont touch it!!!

[redrider9045]

its those yfz's

[JR3]

my friend beats his to death and no problems yet

[creechfan]

if you casually ride a bone stock bike, and change the oil every 20hrs, you should go 200 hrs + before a rebuild.

that is y i am keeping my motor all stock! it has done awsome for me and i really really like this ATV....

i know a lot of guys dont like to here this, but the more you stray from stock the more problems you will have depending on how performance orientated the motor is stock I.e Warrior motor VS. a YFZ motor. BUT that is not allways the case!. I am going on what i have seen personaly.

There is one exception though, TIP TOP engine builders that get high dollars for there race motors, but even then some of them can have problems.

[maggiesboy]

I've had mine since April. No problems until yesterday. I was changing my oil and noticed a couple of drops of coolant coming from the weep hole on the water pump. I'm very happy that I change oil every ride. I caught it early!

[daddio]

Originally posted by maggiesboy
I've had mine since April. No problems until yesterday. I was changing my oil and noticed a couple of drops of coolant coming from the weep hole on the water pump. I'm very happy that I change oil every ride. I caught it early!
change the waterpump seal, and you'll solve the coolant leak. this is a very common problem. even on the dirt bikes.

[111quadracer]

As for everyone having these problems. First, think of what you're doing. Most of the time, something we have done has caused the problem. The moment you start messing with the carb, not cleaning air filter properly, adding a pipe, etc, problems can arise if you do not do everything correctly. As far as the jetting, I'm still having trouble with my bike too. It runs a little too lean at lower RPM's. And the pipe gets red hot. Everyone I've talked to is having this problem. Even the pros are struggling with this problem. The biggest problem I've been finding is getting the bike set up correctly. The front end geometry is a little screwed up. I run TT with my bike, and trying to mount a sway bar and get the bike to set low is nearly impossible. You just have to keep playing with it and trying different things. Yamaha built a rocket when they built this bike. I'm keeping my motor stock, b/c it's more reliable. And, I like beating guys that have faster bikes than me. I race in the 265/450A class at Birch Creek this past weekend, and I beat a YFZ that I know is not stock, and I also beat a KTM 450 that is very very fast. Both of these bikes were faster than mine on the long straights. The only thing I've done to mine is put a Duncan Pipe with the K&N pro-flow kit. I'm keeping it simple for now, so I don't have issues with my bike.

[daddio]

btw the waterpump seal is a very common problem. the solution comes from Yamaha themselves. the first year yfz's had an incorrect waterpump seal, and yamaha updated the part number. 2005 and le models were fixed.
but you are correct, in that most of the problems with the yfz stem from what the owners do with them. riding/racing ANY bike hard, breaks things.
your header pipe will always "glow" orange even if the bike is jetted correctly. the stock header pipe is too thin to dissapate all the exhaust heat. jet your bike by the "seat of the pants" method, and keep an eye on you spark plug. ignore the orange pipe. if it really bothers you, have a header shop make you one from thicker tubing.

[phildampier]

I got one of the first ones and the only problems i have had so far is the battery thing, cracked swing arm, and a blown water seal. Mine has had the crap raced out of it. the a arms are now straignt since i keep hitting rocks in the desert but they havent broken yet.

[creechfan]

I have a 04 YFZ and have not had any problems with my water pump seals or head plug or battery.

I too know the felling of beating guys with more moded quads than my own. It is awesome!! I just wish I lived some where out west or down south so I could ride MX or TT still…..guess I’ma have to wait till the indoor tracks open
:p