2007 Grizzly 700 FI Automatic 4x4
MSRP: $7999-$8349 (as tested); Outdoorsman Edition and Ducks Unlimited Edition, $8899
Engine type: Single-cylinder, four-stroke SOHC
Displacement: 686ccBore x stroke: 102.0x84.0mm
Cooling: Liquid-cooled with fan assist
Carburetion: Yamaha Fuel Injection (YFI), 44mm throttle body
Drive system: Shaft, 2x4/4x4
Transmission: Yamaha Ultramatic V-belt with high/low range, reverse, engine-braking, diff-lock
Front suspension type/travel: Dual A-arms, independent/7.1 in.
Rear suspension type/travel: Dual A-arms, independent/9.5 in.
Front tires: AT25x8-12 with aluminum wheels
Rear tires: AT25x10-12 with aluminum wheels
Front brakes: Dual hydraulic discs
Rear brake: Dual hydraulic disc
Wheelbase: 49.2 in.
Claimed dry weight: 600 lb
Ground clearance: 11.8 in.
Length/width/height: 81.3/46.5/48.8 in.
Seat height: 35.6 in.
Turning radius: 126.0 in.
Fuel capacity: 5.3 gal.
Front/rear rack capacity: 99/187 lb
Towing capacity: 1212 lb
Headlight: Dual 35-watt halogen
Instrumentation: Fuel gauge, speedometer, odometer, hourmeter, dual tripmeters, clock; gear position indicator
Colors: Hunter green, Steel blue, red; Realtree Hardwoods High Definition camo
Don't Put That Old Grizzly Out to Pasture Yet!
Thumper Racing's Grizzly 690With the release of the new and improved Grizzly 700, there's no doubt many are now viewing their old 660 as too long in the tooth to be any good anymore, but an equal number of riders with great sums of money invested into the reliable workhorse are unwilling to part ways just yet. There's a reason for the Yamaha's market dominance-its easygoing and can-do personality naturally appeals to a broad spectrum of buyers. But faced with more powerful competition, the Grizzly was finding it harder to stay in the game.
The stock motor is good, but like all motors, there is room for improvements. Enter Thumper Racing and its 690 kit. Owner Gary Hazel's mantra should be "No replacement for displacement." Boosting the engine size on the Grizzly gave it the power to keep up with the rest-proof that bigger is better in places other than a Beverly Hills plastic surgeon's office.
Before any displacement augmentation occurred, though, Hazel and crew applied their 12 years of engine-building experience to deciding just how to tackle the Yamaha mill. Any course of action had to adhere to Thumper's performance, reliability and cost philosophy. That translates into a big-bore kit that provides a performance gain without weakening the engine, all at an affordable price-the 690 kit is only $339.
We got to sample Thumper's newest big-bore less than a week before heading to Montana to try out Yamaha's revolutionary 700. That was a good thing because both are roughly the same size, with Thumper's 690cc to the factory's 686cc. The similarity stops there. Not only do they differ in chassis but power delivery accentuates this as the 690 erupts. Besides the obvious chassis difference, the Thumper Grizzly leaps ahead when you mash the throttle, while the 700 has a deceptive smoothness to its power delivery. The root of this quick-hit phenom is the forged Wiseco 102mm piston. The lightweight piston lets the engine spin up fast, and the power comes on in no time. Why a 102mm bore? Thumper found that the stock cylinder has enough wall thickness to allow them to just bore in the 102mm piston without requiring a sleeve install. So the cost stays down and, even better, the 11:1 compression ratio still permits pump gas with no overheating problems.
Hushing the happy beast is a stealthy $299.95 FMF PowerLine muffler. In fact, other than Thumper's serviceable oil filter ($119) and some Klotz 10w40 MX4 oil, that was it for engine mods on this Grizzly. The motor's potential didn't require a lot of time and effort to tap. Of course, Hazel did acknowledge he could have ported the head and thrown in a high-performance cam, but he chose to treat us to just a basic kit. And we were satisfied with that nibble. The 4x4 offered punch, yet the power is very user-friendly and the big ute was plenty manageable on the trail-parts of its sales-winning charm.
Like most 4x4 owners, Hazel opted for larger, more aggressive tires, installing a set of AMS Swamp Fox meats and AMS wheels, which are $77.95 each. The super-aggressive design of the affordable $66.95 tires allowed the Grizz to go everywhere and do anything. Without the increased ponies, bigger lugs easily overwhelm most stock engines with gearing configured to work optimally with smaller stock units. Not the case here-the revitalized Grizzly had its claws out and itched for any trail combo. A Thumper Pro Seat cover kept us attached to the quad. The $75 traction seat offered the proper amount of grip without being too grabby-as in it won't pull down your pants. And because it's a camo utility, Hazel had to outfit it with a $670 Warn winch and front bumper to add some utility cool factor. Bottom line here is there is no need to put that old bear out in the trees just yet; it just needs a little engine augmentation, Thumper Racing-style.