Ok heres the story.......i broke my arm 4 months and my quad has been seating in the garage every since....today i went to change the oil...did so.....and try to start the quad and the battery was dead....charged the battery.....tryed to start it and it wouldnt start....so i jumped started it and it ran ok backfired alot and then just stallled....the only way its alowing me to start it if the light switch is on and it has to be bump started down a hill....weird thing is the lights dont come on when the quad is running......anyone can help me with this i would greatly appreciate it.....

 

what year is it??? 04 05 has a proplem with the charing system.. if u dont have the lights on the system doesnt charge enough... herd it from dirt wheels 06 yfz450 issue

 

i figured thats why the lights arent working but why wont the quad stay running?

 

are u using the same gas since for 4 months????

 

yes i am using the same gas....is that bad?

 

i would drain the gas and but new gas... but thats me i dont even like gas thats been sitting for 1 month

 

would that cause my bike not to run?

 

maybe it couldnt hert to try

 

I am no expert but the gas would be not be the problem and I thought that was the fix for the 04's, 05's to turn the lights on to charge the system when riding. If I remember right the YFZ has a higher charge than a 12 volt system (14 maybe) so if that is what you are using the battery will never reach full charge and it could be at a state where it now will never recharge.

Support is needed and I can't recall the screen name[img]i/expressions/face-icon-small-sad.gif[/img]

 

Searching and found:

from www.douggust.com/content/AskPages


Q: I have heard of battery problems with the YFZ450's where it overcharges the battery and then runs poorly. Have you guys heard of this problem and any ways to fix It? And also was it just some of the first ones from Yamaha or is it just a general problem?


Thanks

Mike



A: We're glad you asked this question. There is a lot of confusion about this issue, so we'll give you the straight scoop.



With the help of Jeff at M&M Cycle in Kalamazoo, MI, we have pieced-together the facts.



First of all, there is nothing wrong with the quad or its electrical system. However, it does require special maintenance procedures and riding practices (as does any race machine)



There are two main issues which lead to the YFZ battery problem:



1) The battery itself: The battery is a Dry-cell, sealed battery. Unlike regular batteries, its internal voltage is about 13.5V (as compared to about 12.6V for standard batteries.)

Due to the higher voltage, you need to use a special charger for it. Regular battery chargers will only charge it to about 12.5V max. This is only about 70% of this battery's capacity.

Several companies make the higher voltage chargers, but the recommended one is made by Yamaha. It's called the Opti-mate 3, and is available from any Yamaha parts dealer for about $60.



2) The YFZ is a race quad, pure and simple. However, when trail-riders get ahold of this quad, problems with the battery can occur if they don't follow some procedures Here's why: To maximize Horsepower, the charging system on the YFZ was designed for racing. High RPMs (racing conditions) are required to properly charge the electrical system. The quad was designed this way because electrical charging robs HP. For racers, there is no problem (reported), but for trail riders there may be. When you're out trail riding, high RPMs are usually not the norm. Plus, the electric cooling fan is often in use due to the low speeds. This fan runs right off the battery. The combination of the fan and low RPMs results in the battery draining while you ride, and this can result in ignition problems.



So, what can be done about it? Here are some key things to do with the YFZ:



A) It is important that the battery is fully charged to its maximum 13.5V prior to being installed in the YFZ for the first time. If it was not fully charged before installation, that battery may not accept a full charge (ever) due to the battery 'memory'.



B) Never use a standard battery charger. Only use a Yamaha Opti-mate 3 (or equivalent)



C) Only use the Resistor-type Spark Plugs from the factory.



D) When trail riding, if the fan is coming on all the time, turn ON the headlights. By turning on the headlights, the charging system activates and will allow the electrical to keep up with the load of the fan without draining the battery.



E) After trail rides, top-off the battery with the Opti-mate 3 charger. (It comes with a quick-connect plug so it's easy to use frequently)



So, is this a design flaw by Yamaha? No. This quad was design by and for racers and racing conditions. It's the slow, trail-riding conditions which can result in electrical drainage. I wouldn't have though that turning ON the headlights would help with battery drainage, but it does. Yamaha doesn't want to harm the Horsepower by increasing the charging system output, and I hope they don't (for racer's sake). But, maybe in the future, they will offer to sell some sort of 'electrical boost kit' for the slow trail riders to install.



Personally, I commend Yamaha on the overall design of the YFZ450, inside and out. If we've got to turn on the lights to keep the juice up during trail rides, so be it.



-Pro Staff