2003 yamaha grizzly 660 4x4 atv, right side rear axle/cv joint came lose at differential

If the CV Joints are new and correctly inserted, the most likely culprit for the noise would be the brakes. Remove the front wheels and turn the hub.

It could also be the front differential, or failed wheel bearings. Details in the link.

https://www.google.com/search?q=Yamaha+big+bear+350+4x4%2C+front+wheels+grinding+noise

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What exactly are you trying to do? I'm assuming you meant 'Compression'.
Are you refering to the compression in the cylinder? I don't think the early Grizzlys had fuel injection so that won't be the issue. Engine compression isn't usually that high and is released when you remove the spark plugs.

1. First jack up vehicle.
2. remove tire/rim
3. remove cotter pin and castle nut from the end of the axle.
4. disassemble spindle from upper/lower ball joints'
5. separate spindle from axle by pulling spindle away from the vehicle.
6. with two hands grasp axle and pull firmly to remove axle assembly from differential.
7. remove torn cv boot, clean all old grease from cv joint.
8. apply new grease and install new boot.
9. secure clips on cv boot.
10. Reassembly is reverse of disassembly.
11. Consider purchasing the service manual for your make /model of atv from amazon. This manual will have step by step instructions and pictures for any repair or maintenance that you will need to perform.

If the axle keeps popping out of the differential it probably has a worn C-clip on the joint, or the clip is missing. On the splined end of the joint there is a groove that holds this clip. Your local Yamaha dealer should have these clips or be able to order them. Daniel

[PDF]GRIZZLY 450 YFM45FGX OWNER'S MANUAL - Yamaha

www.yamaha-motor.com/.../lit-11626-21-46_griz... Yamaha Motor CompanyThis ATV should not be ridden by anyone under 16 years of age. ... Product and specifications are subject to change without notice. ...... Recoil starter. 4. Throttle ...

Removing The Rear Brake Drum & Shoes on Grizzly 600 ...

? 5:04
www.youtube.com/watch?v=n5oO7v3nT6s
Mar 11, 2012 - Uploaded by myquadrepair
Removing the rear brake drum & shoes on Yamaha grizzly 600. ... Yamaha Big Bear Oil Change and More! - Duration: 10:43. by jfrost77hd ...

HONDA FOREMAN REAR BRAKE CHANGE PART 1 ...

? 11:49
https://www.youtube.com/watch?v=xQanZdlDCI0
Jul 17, 2012 - Uploaded by 400EX99N
HOW TO CHANGE REAR BRAKES ON A HONDA ATV. ... is this about the same for a 2004 yamaha big bear 400? Read more Show less.

drian engine oil take side cover should be an 8m to 12m depending on the model... the stator might be attached to the cover or might have a mount holding it into place to the fly wheel

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.

The "upgrade" can be done but it ain't cheap! The outer hub has to be a 2005 for clearance of the CV joint and there are clearance problems around the front pumpkin. If you keep the angle to near stock, the knuckles are very reliable. Make them bend too far, with a lift kit and they will break.
For brakes: EBC Severe Duty FA159SV in the front and FA314SV in the rear