Honda TRX450S
Covered Models
- 1998 Honda TRX450S
- 1999 Honda TRX450S
- 2000 Honda TRX450S
- 2001 Honda TRX450S
Honda TRX450S
GENERAL DATA | |
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Producer | Honda |
Model | TRX450S |
Year |
1998- 2001 |
Image Honda TRX450S
Honda TRX450S Review
Let’s talk about the old Honda TRX450S Foreman. This was Honda’s workhorse quad from the late 90s. Not like the crazy fast TRX450R sport quad that came later – this baby was all about getting stuff done, a real utility ATV!
The Foreman 450S was built tough with a solid rear axle so you could haul and tow without breakin’ stuff. Sure, you could have fun on the trails too, but this machine was made for WORK first.
Honda didn’t change these quads much over the years. Why mess with something that ain’t broke, right? They’d tweak the looks a bit, maybe improve the shocks or squeeze a bit more torque out to the engine, but nothing crazy. Just making a good thing better.
Don’t get the “S” mixed up with the “R” model though! The TRX450R was a whole different animal – it was a race-ready sport quad with independent suspension and a screaming engine. The “S” was part of Honda’s Foreman family – the blue-collar heroes of the ATV world.
The Foreman 450S stuck around for quite a while, which tells you something about how much people liked them. Farmers, hunters, and regular trail riders all loved these quads because they could work hard Monday through Friday and still give you some weekend fun without emptying your wallet at the repair shop. These things were built to last!
TEHNICAL SPECIFICATIONS
ENGINE | |
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Bore and stroke | 90.0×68.0 mm(3.54×2.68 in) |
Compression ratio | 8.5:1 |
Displacement | 432.6 cm3(26.39 cu−in) |
Engine idle speed | 1,400±100 r rpm |
Spark plug, standard | DPR7EA-9 (NGK), X22EPR-U9 (DENSO) |
Spark plug gap | 0.8 0.9 mm (0.03-0.04 in) |
Valve clearance | 0.15 mm (0.006 in) |
Start Type | Electric start (plus backup recoil starter) |
DIMENSIONS | |
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Overall length | 1,961 mm (77.2 in) |
Overall width | 1,156 mm (45.5 in) |
Overall height | 1,144 mm (45.0 in) |
Wheelbase | 1,271 mm (50.0 in) |
Dry Weight | 260 kg (573 lbs) |
TRANSMISSION & GEAR RATIO | |
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Primary reduction | 2.103 |
Secondary reduction | 2.1 |
Final reduction Front | 3.153 |
Final reduction Rear | 3.153 |
Gear ratio 1st | 4.083 |
Gear ratio 2nd | 2.388 |
Gear ratio 3rd | 1.608 |
Gear ratio 4th | 1.178 |
Gear ratio 5th | 0.848 |
Reverse gear ratio | 4.781 |
CHASSIS & SUSPENSION | |
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Caster angle | 3.0° |
Trail Length | 7 mm (0.3 in) |
Front suspension type | Independent double-wishbone |
Front suspension travel | 150 mm (5.9 inches) |
Rear suspension | Swingarm with a single shock |
Rear suspension travel | 170 mm (6.7 inches) |
FUEL & LUBRICANTS | |
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Tongue and rear cargo weight | 60 kg (133 lbs) |
Fuel tank | 12.0 (3.17 US gal, 2.64 Imp gal) |
Fuel reserve | 2.7 (0.71 US gal, 0.59 Imp gal) |
Engine oil | 2.7 (2.9 US qt, 2.4 Imp qt) |
Engine oil capacity | 2.0 l (2.1 US qt, 1.8 Imp qt) |
Recommended oil viscosity | SAE 10W-40 |
Oil Type | Honda GN4-Stroke oil or equivalent |
Rear final gear case oil | 90 cm³ (3.0 US oz, 3.2 Imp oz) |
Rear final gear case oil capacity | 2.0 (2.1 US qt, 1.8 Imp qt) |
Rear final gear case recommended oil | Honda shaft drive oil or equivalent HYPOID GEAR OIL SAE 80 |
Rear final gear case drain plug torque | 12 N m (1.2 kgf-m, 9 lbf ft) |
Differential oil | 190 cm³ (6.4 US oz, 6.7 Imp oz) |
Differential oil type | Honda shaft drive oil or equivalent HYPOID GEAR OIL SAE 80 |
Differential oil plug torque | 12 N m (1.2 kgf-m, 9 lbf ft) |
TIRES | |
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Tire size, Front | AT25×8−12×∗ |
Tire size, Rear | AT25×10−12×∗ |
Tire brand | KT401C DUNLOP, KT405C DUNLOP |
Recommended pressure | 25 kPa (0.25 kgf/cm2, 3.6 psi) |
Minumum pressure without cargo | 28 kPa (0.28 kgf/cm2, 4.0 psi) |
Maximum pressure | 22 kPa (0.22 kgf/cm2, 3.2 psi) |
Recommended pressure with cargo | 25 kPa (0.25 kgf/cm2, 3.6 psi) |
ELECTRICAL & LIGHTS | |
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Battery | 12 V-12 Ah |
Generator | 0.31 kW/5,000 rpm |
Sub fuse | 15 A×2,10 A×2 |
Main fuse | 30 A |
Head light (Low/High) | 12 V 25/25 W × 2 |
Assist headlight | 12 V 45 W |
Taillight | 12 V 5 W × 2 |
Neutral indicator | LED |
Reverse indicator | LED |
Oil high temperature indicator | LED |
BRAKE | |
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Front brake type | Hydraulic disc brakes |
Rear brake type | Drum brakes |
LOADING | |
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Maximum weight capacity | 220 kg (485 lbs) maximum |
Front cargo rack weight limit | 30 kg (66 lbs) |
Rear cargo rack weight limit | 60 kg (133 lbs) |
Tow weight limit – combined weight of trailer and all cargo in trailer | 385.5 kg (850 lbs) |
Tongue weight | 30 kg (13.6 lbs) |
Let’s see more about tech specs
So let me tell you all about what makes the Foreman 450S tick. This ain’t no fancy brochure – just the straight talk on Honda’s workhorse quad.
The heart of this beast is a 433cc four-stroke thumper that’s liquid-cooled. It’s got that overhead valve setup that mechanics love because it’s dead simple and lasts forever. The engine’s built with an aluminum cylinder and steel sleeve so it won’t wear out when you’re putting in those long days.
Honda gave it a longer stroke than bore (about 86mm bore and 75mm stroke if you’re wondering), which is why these things pull like a mule even at low RPMs. They don’t rev super high with that 9:1-ish compression ratio, but who cares? They’ll run on regular gas and keep chugging along when other quads are in the shop.
For fuel, you’re looking at an old-school carburetor – none of that fancy fuel injection stuff. It’s got a choke for those cold mornings and once you figure out its quirks, it’ll start right up. The oil system is a basic wet sump setup that keeps everything slick, and the cooling system cycles fluid through the engine and radiator to keep temps steady even when you’re working it hard.
The ignition’s a CDI system – real reliable – and Honda was smart enough to give you both an electric start and a pull-start backup. There’s nothing worse than being stuck miles from home with a dead battery!
Now the drivetrain – this is where the Foreman shines as a worker. You get a five-speed manual transmission with reverse and a wet clutch that can take a beating. Power goes through a shaft drive instead of a chain, so you’re not constantly adjusting and lubricating like on some quads.
It’s mostly a 2WD machine with that bulletproof solid rear axle. Yeah, it ain’t as comfy as independent suspension, but you can haul loads all day without breaking stuff.
The frame’s just tough steel – nothing fancy, but it’ll last forever. Up front, you’ve got independent double wishbone suspension that soaks up the bumps pretty well. The rear’s a swingarm with that solid axle I mentioned, usually with just one shock. You can adjust both front and rear if you’re carrying heavy loads.
Brakes are hydraulic discs up front for good stopping power and a sealed drum brake in the back that won’t get gunked up when you’re splashing through mud and creeks.
The wheels are plain steel – not pretty but they won’t bend when you hit a rock. Tires are all-terrain and handle most stuff decent enough.
Size-wise, it’s big enough to be stable but not so huge you can’t get through tight trails. Ground clearance is pretty good for a utility quad, and the seat height works for most folks.
What really makes this a working machine are the sturdy front and rear racks for strapping down gear and a decent towing capacity for hauling stuff around your property.
Honda added also some basic lights too, so you can keep working after the sun goes down if you want.
Souping Up Your Honda Foreman 450S – The Real Deal
So you want to get more out of your trusty old Foreman, huh? I’ve been modifying these things for years, and let me tell you what actually works:
Engine Mods – Wake That Thumper Up!
Better Air Filters: Ditch that stock filter and grab a K&N or UNI filter. These things breathe way better and you can just wash them instead of buying new ones all the time. If you ride in real dusty spots, slap an Outerwears pre-filter on there too. K&Ns are the best but they’ll run ya about 60-80 bucks. You can find cheap knockoffs for 30 bucks, but I wouldn’t trust them with my engine.
Carb Jet Kits: Your Foreman’s running too lean from the factory – Honda does this for emissions. Grab a Dynojet kit and you’ll feel the difference right away, especially if you’ve already put on that air filter. Dynojet makes the best stuff, around $120, but you can find basic kits for $60 if you’re pinching pennies.
Camshafts: Now we’re getting serious! A Hot Cams stage 1 will wake that engine right up. Just remember – different cams do different things. Want low-end grunt for mud? That’s a different cam than if you want high-RPM trail riding. These’ll run you $200-400 depending on how wild you want to get.
Big Bore Kits: The nuclear option! Cylinder Works makes good kits that’ll bump you up to 500cc or more. Prepare to spend $500+ and probably have your buddy who’s good with engines help you install it. These ain’t for beginners!
Exhaust – Let That Thing Breathe!
Slip-On Mufflers: Easiest mod you can do. Unbolt the stock can bolt on something from FMF or Yoshi, and instantly sound cooler while gaining a few ponies. A good aluminum slip-on is around $300, but those fancy titanium ones can hit $600. Your choice if the weight savings is worth the extra cash.
Full Systems: If you’ve done other mods, a full header-back system will let everything work together. FMF makes the Power Bomb header that works real nice on these Foremans. Expect to drop $600-800 for a quality setup. Again, titanium is lighter but pricier.
Suspension – Smooth Out The Rough Stuff
Better Shocks: The stock shocks are okay for farmwork but garbage on trails. Fox and Elka make amazing replacements, but they ain’t cheap -we’re talking $1500+ for a full set of the good stuff. If you’re on a budget, look for used take-offs from newer Honda models that might fit.
Long Travel Kits: These widen your stance and give you more wheel travel. Great for stability and soaking up bumps at speed. Houser makes good kits, but you’ll drop $2000+ easily. Plus, you’ll need wider tires to match that new stance.
- Heavy-Duty Springs: If you’re always hauling or towing heavy stuff, grab some stiffer springs from Eibach. They’ll keep your quad from sagging under load. These are pretty reasonable at $150 or so for a set.
Carburetor Upgrades
Bigger Carbs: A Mikuni or Keihin carb can replace your stock one for better throttle response. I like the Mikuni TM40 if you can find one. They run about $400 but you’ll need to rejetting to make it work right.
Fuel Injection Controllers: If you’ve somehow gotten fuel injection on your Foreman (some guys swap newer Honda parts in), a Power Commander will let you dial in the perfect fuel mixture. They’re about $400 but worth every penny if you’ve done other mods.
Other Cool Stuff
Tires and Wheels: Nothing transforms how your quad rides like new rubber! For mudding, I like ITP Mudlites. For trails, the Maxxis Bighorns are hard to beat. Budget about $600-800 for a full set with decent aluminum wheels.
Protection: Ricochet makes the best skid plates for these quads. Your oil pan and frame will thank you when you slam into that hidden rock. Figure $200-300 for good underbelly protection.
Winches: Get stuck a lot? Slap a Warn 2500 up front. Saved my bacon more times than I can count! They run about $300 but get the synthetic rope, not steel cable.
Lights: Those stock headlights are like birthday candles. Some LED replacements or a light bar will change your night-riding game completely. You can start with $100 LEDs or go crazy with $500 worth of premium lighting.
Honda Foreman 450S vs The Competition
Let’s get real about how Honda’s workhorse quad matched up against the other utility ATVs back in the day. Remember, the Foreman 450S wasn’t trying to be a race quad – it was built for gettin’ stuff done!
Who Was It Up Against?
- Yamaha Kodiak 400/450: These Yamahas were solid machines that could work hard and play hard too. They had that sturdy rear axle like the Honda, but some models came with 4-wheel-drive which the Foreman S didn’t have. That was a big deal if you worked in mud or snow.
- Polaris Sportsman 400/500: Man, Polaris really changed the game with these. They had independent rear suspension instead of a solid axle, so they rode smoother over rough stuff. Plus they all had 4WD. The downside? More parts to break when you’re really working them hard.
- Suzuki KingQuad 400/450: Suzuki made some darn good utility quads. The KingQuads were reliable and also offered 4WD on most models. They were always solid competitors.
- Kawasaki Prairie 360/400: The Prairie line was popular with folks who didn’t want to mess with shifting. Most had automatic CVT transmissions instead of the Honda’s manual 5-speed. Easier to ride but you lost some of that direct control.
What Made the Honda Foreman Stand Out?
- Bulletproof Reliability: Honda just built ’em better, plain and simple. When your livelihood depends on your quad starting every morning at 5am in the freezing cold, that red Honda logo meant something.
- Manual Transmission with Real Clutch: For old-school riders, nothing beats a proper manual transmission. You could engine-brake down steep hills and really control exactly how much power was going to the wheels. No slipping belt drives here!
- Tank-Like Rear Axle: That solid rear axle might’ve bounced ya around a bit, but good luck breaking it! You could load up the rear rack with way more weight than Honda recommended and that axle just kept on ticking.
- Simple Design: The Foreman was just… simpler. Less fancy electronic gizmos to go wrong, easier to work on in your garage, and fewer specialized tools needed for maintenance.
Where the Foreman Fell Short:
- Only 2-Wheel-Drive: This was probably the biggest knock against it. When things got slick, those other quads with 4WD just went places the Foreman couldn’t without a lot more effort.
- Rough Ride from That Solid Axle: Sure it was tough, but man did you feel every rock and root through that seat! The Polaris with IRS would float over the same trail that was beating you up on the Honda.
- No Power Steering: Your arms got a workout steering this thing, especially in tight woods or after a full day of plowing snow. Some of the competition started offering power steering while the Foreman was still old-school manual.
- Old-Tech Engine: The overhead valve engine was proven and reliable, but it wasn’t winning any horsepower contests against the overhead cam designs some competitors were using. Dependable? Yes. Exciting? Not so much.
Bottom line, the Honda Foreman 450S was the ATV for folks who valued “it just works” over flashy features. Honda built these things like tanks, and that manual transmission gave you control that automatic quads just couldn’t match. Yeah, it lacked the cushy ride and 4WD that others had, but for many ranchers, hunters, and property owners, the Honda’s legendary reliability made it the only choice worth considering.
Honda TRX450S – Troubleshooting
Problem | Description | Solution |
Engine won’t start | No crank, no spark, or only turns over | Check battery charge, inspect spark plug, check kill switch, and confirm fuel delivery |
Engine turns but won’t fire | Starter works but no ignition | Clean/replace spark plug, check ignition coil, test CDI unit, inspect carburetor/fuel lines |
Hard starting (cold) | Engine struggles to start when cold | Use choke properly, clean carburetor, adjust fuel/air screw, check valve clearances |
Loss of power | ATV feels sluggish or bogs down | Clean air filter, check fuel filter, clean carburetor, inspect exhaust for blockage |
Engine stalls suddenly | Shuts off while riding or idling | Check for loose electrical connections, clean carburetor jets, test CDI and coil |
Overheating | Engine gets too hot or starts smoking | Check coolant level (if liquid-cooled), clean cooling fins, avoid idling too long |
Excessive smoke | Blue smoke (oil burning) or black smoke (rich fuel) | Blue: Check valve seals, piston rings. Black: Adjust carburetor, clean air filter |
Transmission hard to shift | Gears stick or won’t engage smoothly | Check clutch adjustment, inspect shift linkage, change transmission oil |
Starter not engaging | Pressing start button results in click or nothing | Test starter relay, solenoid, battery voltage, or starter motor |
No electric start function | No response when pressing start button | Check fuses, battery voltage, ignition switch, starter button wiring |
Battery won’t hold charge | Battery drains quickly or won’t stay charged | Test stator/rectifier, look for parasitic drain, replace old battery |
Lights not working | Headlight/taillight out | Check bulbs, fuses, wiring harness, and switch connections |
Poor idle | Engine stalls or surges at idle | Adjust idle screw, clean pilot jet, check intake boots for air leaks |
Fuel leaking from carburetor | Gas dripping from overflow or bowl | Clean/replace float needle, check float height, replace gaskets |
Honda TRX450S – Q & A
ENGINE & MECHANICAL
ELECTRICAL SYSTEM
CARBURETOR & FUEL SYSTEM
DRIVETRAIN
CHASIS & SUSPENSION
BRAKES
Honda TRX450S – Maintenance Schedule
MAINTENANCE SCHEDULE | |||
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Part | Type of maintenance -> whichever come first | Hours | Miles |
Fuel line | Inspect | 200 | 1200 |
Throttle operation | Inspect | 200 | 1200 |
Carburetor choke | Inspect | 200 | 1200 |
Air cleaner housing | Clean | 100 | 600 |
Air cleaner housing drain tube | Inspect | 100 | 600 |
Spark plug | Inspect | 100 | 600 |
Valve clearance | Inspect | 100 | 600 |
Engine oil | Replace | 100 | 600 |
Engine oil filter | Replace | 100 | 600 |
Engine idle speed | Inspect | 100 | 600 |
Drive shaft boots | Inspect | 100 | 600 |
Rear final gear case oil and differential oil | Inspect every 2 years or -> | 200 | 2000 |
Brake fluid | Inspect | 100 | 600 |
Brake shoe wear | Inspect | 200 | 1200 |
Brake system | Inspect | 100 | 600 |
Reverse lock system | Inspect | 100 | 600 |
Skid plates, engine guard | Inspect | 100 | 600 |
Clutch system | Inspect | 100 | 600 |
Suspension | Inspect | 100 | 600 |
Spark arrester | Clean | 100 | 600 |
Nuts, bolts, fasteners | Inspect | 200 | 2000 |
Wheels/tires | Inspect | 100 | 600 |
Steering shaft holder bearings | Inspect | 200 | 1200 |
Steering system | Inspect | 200 | 1200 |