Nicholas Fluhart

August 8, 2009

Project: Honda Foreman 450 to 475

Filed under: Project: 475 Foreman — Nicholas Fluhart @ 9:18 pm

Most of the ATV’s I’ve owned (my personal ATV’s I buy to keep, not to be confused with the many ATV’s I buy and sell as part of my business) have been sport or racing bikes, so when I had the opportunity to purchase this 1998 Honda 450 Foreman I envisioned building a magnum industrial/utility machine. And that’s just what I did.

Before

After

I had a friend who received this ATV from his cousin who is a poultry farmer in northern Arkansas. The ATV was used daily on the farm and from 1998 to 2004 acquired over 15,000 miles. Yes, that’s a lot of miles for an ATV. But even harder to believe is the engine, differentials, and axles were all completely stock and in good condition.

Lots of miles and lots of hours

Lots of miles and lots of hours

That was until he handed the key to his son who promptly sunk it in a mud hole and drowned out the engine. He brought it to my shop and I completely rebuilt the engine from top to bottom. A few months later the same thing happened again. This time, due to the digestion of sand and sediment, other components in the engine were beginning to fail, such as the cam chain adjuster and the clutch. Rather than continuing to dump money into something his son would systematically destroy, he decided to sell it. I offered him $500 and he gladly took it. I knew I could part it out for twice that amount, so I felt safe with my offer.

– Initial Inspection

Now it was time to inspect the machine from front to back and determine if it would be worth restoring and what parts would be needed. I knew the engine would need a complete overhaul, but the axles and differentials were sound. It did, however, need most of the bearings replaced and both front and rear brakes needed to be completely rebuilt. I obtained parts pricing from my extensive parts networks and calculated it would need about $500 in parts. I estimated an additional $500 may be needed for unseen damage and the many accessories I planed to install. This would put my total investment at $1500 and I would have a completely rebuilt, ready to ride, excellent ATV loaded with all the accessories and equipment I needed, like which I could not have bought one for that amount. Of course, as with many personal projects, you can’t really put a dollar value on your time invested. It has to be a labor of love.

– Chassis

The first thing I did was strip it down to the frame. The frame consists of square backbone rails and round tubing. Frames can easily rust through in places unseen, so I painted the entire frame in a semi-gloss black. On the front, the A-arm bushings and ball joints were in good condition so I just painted the A-arms. I inspected, adjusted, striped, and painted the tie rods in a low-gloss silver. The front axles and boots were in great shape, but I did have to replace the wheel bearings and seals. The front differential was in excellent condition and clean inside so I polished the exterior to a shine and applied a clear coat to prevent oxidation. I performed the same procedure on the rear including replacing the axle bearings in the axle housings.

One thing that really showed the mileage on the machine was the left foot peg on the gear shift side. The teeth were worn smooth from extensive use of the gear shifter. See the difference between the left and right foot pegs below. Aside from that, they were straight and functional so I gave them a shot of paint and let them go.

Left Foot Peg

Left Foot Peg Worn Smooth

Right Foot Peg

Right Foot Peg

Up on the handlebars the grips were also worn smooth so I replaced them with a pair of OEM Honda grips from a new TRX450R race bike. Another thing I considered was to replace the instrument cluster because, as you can see in the odometer photo above, the LCD display is damaged. However, upon further consideration I decided to keep the unit. Although it is damaged, it is perfectly functional. But the main reason I decided to keep it was due to the fact that the odometer is the only way I can prove how many miles are on this ATV, because I’m confident no one would believe it otherwise.

The suspension needed some attention. Believe it or not, the shocks themselves were in great shape but the bushings were worn. I cut new bushings and added some shims where needed and they work great.

Left Front Shock

Left Front Shock

Left Rear Shock

Left Rear Shock

– Brakes

The front brakes were still moderately functional. The hydraulic system was sealed but the shoe adjusters were completely frozen, the shoe linings were worn, and the drum seals were damaged. I completely rebuilt the front wheel cylinders. I honed the inside of the wheel cylinders and replaced the seals. I sand blasted the adjusters, soaked them in penetrating oil, and eventually freed them. I installed new shoes and springs as well. I then sand blasted the drums, polished them, and installed new drum seals. I bled the system and it is now functional. I will note that due to the rough drums it doesn’t really stop on a dime, but they will slow you down and eventually lock up. If I get the energy, I may install new drums at some point, but they work well for my purposes.

The rear brake was a disaster. The pedal was frozen and the hand brake cable was broken. The shoes were worn and the whole enclosed brake was full of dried mud. I disassembled the entire assembly and cleaned everything. I had to apply heat to the brake pedal to get it off. Once removed, I cleaned, painted and reinstalled it with plenty of grease on the pivot shaft. I installed new shoes and springs on the brake plate after I freed the brake cam and cleaned and reinstalled it with plenty of grease. I also installed new axle bearings in the brake plate. I sand blasted the drum and installed a new seal in the drum cover after painting it. The brakes worked great.

– Engine

After preparing the chassis, I shifted focus to the engine. I completely disassembled the entire engine to clean and inspect all the components. What does sediment from a mud hole do to the internal components of an engine? Here’s what I found after flushing the sediment from all the parts:

-The wrist pin eye in the connecting rod was worn (a common failure for all the longitudinally mounted Honda engines).

– The main bearings had slack.

– The main clutch plates were worn a little beyond spec.

– The clutch sprag (also called a one-way bearing, although technically it is not a bearing) was defective.

– The cam chain adjuster/tensioner had completely failed.

While surfing the web for parts, I was able to find a nice used crankshaft with main bearings for about $50 plus shipping. This took care of the worn rod and bearing problem. I bought a set of EBC clutch plates (fiber plates) and I happened to have a new set of steel plates that worked. The new clutch sprag was about $80. The centrifugal clutch shoes showed some wear, so I cut new grooves in them to displace the oil and it works great. I purchased a used cam chain tensioner locally for $20. I stumbled upon a 475 big bore kit from Highlifter for less than $200. It included the complete piston kit, cylinder sleeve, gaskets, and a 480 grind Web cam. I hadn’t planned on going with a big bore, but I couldn’t pass up the deal. I did some research and found that this kit had a good reputation, so I went with it. It allows for the use of the stock valve train, carburetor, and intake. I took the cylinder to a friend’s shop who installed the new sleeve. I reworked the head myself and now it was time to assemble the engine starting with the bottom end.

Assembling the Bottom End

Since the engine had been sunk in the mud, I really had to clean the cases, transmission, and bearings thoroughly. One thing that really helped on this project was my pneumatic gasket scraper seen setting on the left side of the table in the photo above. Using Permatex gasket remover also saves a lot of time.

After assembling the bottom end, the top end went together easily. When I first went to start the engine, the starter didn’t have to spin the crank a quarter turn before it fired right up. I ran it at a certain RPM to break in the cam, then it was ready to ride. It has the sweetest sound.

Unfortunately, I don’t have many photo’s of the build, but here’s some pics of the finished product…

Omni Recovery ATV Omni Recovery ATV

If you’re looking for a solid, workhorse ATV, this is one of the best.

Omni Recovery ATV Omni Recovery ATV

For more information and some general specs, as well as a list of all the accessories and equipment I have on my Foreman, see the Honda Foreman 475 Omni Recovery ATV page here.

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1 Comment »

  1. i myself own a 2001 foreman 450 s
    i redid the engine just recently and made it a 495. mine has 11000km and after i redid the engine she hasnt ran better.i want to do the same with mine, take it all apart and redo it, this website might come in help full, thank you

    Comment by rob de koning — November 2, 2009 @ 8:32 pm | Reply


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