20 Most Recent Yamaha 2005 Grizzly 660 Auto 4x4 - Page 2 Questions & Answers

Spark timing needs checking.

only thing I can think of is smaller tires since you cant really change the gearing.

The first thing I would check would be the fuse box. Next, take a look at the the electrical connections for the LCD screen. You've got an off-road toy which most likely is subjected to lots of vibration and occasionally moisture. Do what's necessary to access the back of the dash and check to make sure the electrical connection is still plugged in. If so, unplug it and check for corrosion. According to your description the entire screen is out, so most likely it's not an individual sensor. The bike probably has several electrical ground locations on the frame. Check to ensure they are all clean (bare metal to bare metal) and tight. If it's still not working at this point, you are probably going to need to start looking for broken or grounded wires. You will need a multi-meter to do this properly. If you've never used one before, watch a couple videos on YouTube on how to do an ohms test, then disconnect the battery and test each wire from the LCD screen plug to where ever it terminates. Finally, it's always possible the screen itself is actually dead. I don't know of a way to test to know one way or another. If you have a friend with the same bike, you can always swap the screen to know for sure. Good luck!

General advice: Check that the thermostat is working and not stuck closed or open. Then make sure you have all the air out of the radiator. Also make sure the radiator fan is plugged in and working properly.

check fuel flow and check spark at spark plugs According to an "ATV Rider" 2009 article, "When the Grizzly was introduced in 1998 as a 600cc machine, the top was blown right off the displacement wars of the time." It was replaced in 2002 with Yamaha Grizzly 660, an even bigger engine derived from the well-established all-terrain vehicle (ATV) Yamaha Raptor 660R. Grizzly's 660 cubic centimeter (cc), four-stroke, liquid-cooled single overhead camshaft, five-valve engine performs well in open country, but sometimes it causes serious problems for owners. Before you call a Grizzly dealer, however, trying a few tricks in your garage can save you a lot of time and money. Check the fuel level. Locate the fuel meter indicator on top of the multifunction display. If it does not work properly, open the fuel tank, and push the Yamaha 660 Grizzly side to side. Ensure the fuel is not contaminated by water or rust. If you have not driven your Grizzly 660 for a long time, drain the tank completely, and fill it with a fuel tank cleaner. Check fuel hoses for cracks or leakage. The hoses should be soft and simple to bend. Replace those that show any sign of wear. Check the compression. Screw a compression tester into the spark plug hole, and press the electric starter button. If no compression exists, contact a Yamaha dealer. Wipe wet or dirty electrodes with a dry cloth. The spark plug gap should be checked regularly Correct the spark plug gap. Measure the gap with a wire thickness gauge. If necessary, adjust it to 0.8mm using a screwdriver or replace the spark plug. Use only a Yamaha-specified spark plug. Check the Yamaha 660 Grizzly's battery. Operate its electric starter. If the Grizzly starts quickly, then its battery is in good condition. If the engine turns slowly, check the battery lead connections, and you may need to change the battery. If the engine still does not eventually start, your Grizzly is beyond home repair.

Hey Anon, this is NOT something to "try and learn" how to do..find a professional that is will to tutor you when you do this for the first time! It COULD save you A LOT of $$$$!!!!!

If you have good spark then it's most likely a fuel issue, anything off of idle is dealing with the main jet and metering needle, clean jet and check needle for excessive wear.

Check the fuel flow through the tank valve. There are screens inside the tank that may be blocked and restricting flow.