hi guys, hoping you could help me ID this thing.
i got a nice 4 wheeler from a friend of mine that sells cars, it looks alot like a big bear but i cant find anything more than a engine family sticker under the seat. (7YMXX-307AAA, if that helps any) can you help me ID it?
blue body, engine is not covered. it has independent rear susp., small 10in or so radiator up front (oil cooler?), 4wd red switch and and slide cover for yellow diff. lock switch. green light turns on when 4w engaged, pulls like an ox. display has an analog spedo.
i'm told its a 2006 yamaha, he didnt know anymore than that, he didnt have the title either. on the body it just says yamaha, like the "big bear" or "grizzly" decal was never there. dont know where else to look

thanks

 

Check on the bottom of the cylinder for displacement and also is it automatic or a manual transmission?

 

Only the 2007 and up "air cooled" Big bear 400 and smaller 350 Grizzly has IRS option.
Every other Yamaha that had IRS before 2007 had liquid cooled motors.

The 350 IRS Grizzly/Bruin will be full automatic gas and go CVT belt.
The Big Bear 400 IRS will be semi Auto 5 speed foot shift.

Here is a Pic of both side by side. 2007 Yamaha Big Bear 400 IRS 5-Speed 4X4 ATVs

 

spot on there TLC. ended up being a 07 big bear 400 4x4 manual. found the vin. thanks guys

 

thought i'd give an update. later a little review.
i got this thing for $1600 bucks! got the title. only thing wrong was tires were flat and it needed a little fixin. replaced rear axle seals, changed tires (duro excavators) i'll get better later. repaired tail light and replaced head light, throttle cable, changed all oils, filters, threw some highlifter springs on it. it looks good.
i am extremely pleased with this quad. its strong. i'm about 300lbs and i have no problems riding it, the springs make a huge difference.
i put it to work. threw a tailgated expanded metal rack on the back. i can haul the kids, tools/ chainsaw. cut some trees down, pulled em to the back yard and cut firewood. it helped us burn off the woods in a corner of the property. this thing is amazing. i wouldn't sell it for anything. i'll get some picks up! i got a couple questions tho.
i was thinking of putting a support for the tailgate rack in, heres the rack i got.

Rear ATV Storage Rack Drop Down Basket Steel Cargo Carrier with Tail Gate | eBay

give me some ideas.
i was thinking either the 3 point hitch with a bar that comes straight out and attach a skinny strut, or a metal bar under the rack to carry more weight.
maybe weld a y bracket to attach on either side of the tail light where the oem rear rack bolts on then going down to my trailor hitch. maybe weld a pin to the bottom of the strut, or a bracket to a pin so it can be unbolted and bolted back on pretty easy ... never done this before.
also i'm going to build a snorkel. other than carb and diff vents, of course the 3 lines under the seat.. what other lines need to be brought into the pvc?