More power?

[gaforman]

I want more power out of o2 forman. It is stock except for K&N air filter. My buddy just got a polaris 800 and he is walking my dog. It's killing me. I want to jump up to 26's or 27's to keep up with his 28's in the mud. Help me out, I don't want to have to get pulled out or out run by a polaris.

[MuddnMason]

Truthfully, in the mud, the polaris is going to walk the dog, pretty much no matter what you do. For more power without engine modifications, you need to add an exhaust (HMF Utility for most power), and carb rejetting. If you want to do engine mods, get a big bore kit and a gear reduction for the tranny. Keep in mind, you are not going to make an 800cc motor out of a 450 or 500cc motor no matter what you do to it. IMHO, if you wish to keep up with the big bores in the mud, you need to get a big bore yourself.

[Jake]

Your Foreman is built like a tractor. You could push down a house. You can make modifications to the frame, chassis, intake, exhaust, and the engine, and it will be powerful enough to push a whole row of houses down, but won't be any faster. They weren't built to go fast.
If you want to show somebody how it's done in the mud, you will need god tires. With a behemoth like a Polaris 800, all you can do is point and squeeze. You can do that on a Foreman too, but it isn't going to keep up. You need to take the bike by the horns and take charge of the situation. Stand up on the pegs, toss your weight, make things happen. He can do that too, it just won't do him any good. He's got you with ruts, but if you can keep out of his ruts, you're good. Wide tires with a wrap around tread design help a good deal there too, in particular the rear ones. They grab the edge of a rut for a little extra push, and float a little more in soft stuff so you don't dig down as much.

[TechForeman]

if you are wanting to keep up with him, then tires is your best way to do it. and like jake said, toss your weight around. depending on what kinda tire you get will determine what mods would be best for you.

[gaforman]

I have an 02 forman 450 s by the way. I'm thinking it's time for some outlaw, maybe just 26's or 27's with some new springs. Whose got the best prices on exhaust? and what kind of jet kit do I need to buy. Thanks for all the tips.

[MuddnMason]

On Ebay, HMF Utility is around $225+. The main jet should be around a 135 OEM or you can purchase a jet kit if you wish.

[redstroke]

What about the AC-3 low dollar tractor mufler? Seems cheep!
You Entered Part Number: AC3
No
Picture! Part Number AC3
Description MUFFLER B, C, CA, D10, D
Price $24.94
Core Charge:
$0.00
In Stock Yes

[redstroke]

Or one other cheapo I saw
FCM Part 0313029.00SJ
Vendor Part FO14
Description MUFFLER FORD 501-600-700
List Price $23.21 EA
Spec Memo N/A

[gaforman]

I am another problem too, when I speed up and then let off the gas, especially going down hill my quad back fires. I dont' want to hurt the motor. what could be wrong?

[redstroke]

My quad does that also, my problem is the spring on decompressor on the cam is weak and clicks when it idles, alot of the foremans do this on initial start up for a few seconds, mine does it all the time at idle, this causes it to back fire more than usual, espically when engine braking down hills. Guys is a highlifter (or whoever else sell them) cam worth the extra $60 (power wise), I am going to have to get this replaced soon, also can it be done with out pulling the jug, to get the lifters out?

[Jake]

redstroke said:

my problem is the spring on decompressor on the cam is weak

Nope. I'd bet it's as good as it ever was.

redstroke said:

and clicks when it idles, alot of the foremans do this on initial start up for a few seconds, mine does it all the time at idle,

A lot of them do. Incorrect idle speed makes a click, (depending on the actual speed, it makes noise from properly working and adjusted clutches, or from a perfectly healthy decompressor), incorrect valve adjustment makes a click, the timing chain can make a click, and if it's sat a few days, the big end bearing can make a click until the oil pump primes, all of which require a semi-trained ear to distinguish. All of that is on a mechanically sound engine. if anything has happened, or you have some miles, or havn't kept up with the oil changes, then you can have piston slap, wrist pin knock, big end bearing knock (after the oil is pumping), or any of several clutch issues. Getting rid of the decompressor won't help.

redstroke said:

this causes it to back fire more than usual, espically when engine braking down hills.

Nope. See my first comment above.
In the event that the decompressor was your issue (and it isn't), that wouldn't be the symptom. You might be able to make it backfire, but not under those circumstances.
It more than likely means that your pipe has worn some, and the flow characteristics inside of it have changed since it was new. That's a classic Foreman thing. Just a small fraction to a quarter of a turn out with the mixtrue screw on the carburetor usually sorts it right out.

redstroke said:

Guys is a highlifter (or whoever else sell them) cam worth the extra $60 (power wise), I am going to have to get this replaced soon, also can it be done with out pulling the jug, to get the lifters out?

It's a decent power improvement, but there's a big cost. The cam in the machine is kind of "middle of the road", making the maximum power, driveability, smoothness, and general transparent operation that you can get. Any aftermarket cam is going to enhance one aspect of performance, but it is always (by necessity) at the expense of all other aspects of engine driveability. If you have 28 inch mud tires, you desperately need to shift the powerband to a lower RPM. it'll kill the top end however, you'll never get the engine wound out again. If you have stock tires, and ride only trails, you may want to shift the power band higher. It cruises better on the trail, but you'll have a hard time getting the stock tires to turn if you stop in a mud puddle. Neither will start as easily, or run as well until they're fully warmed up, neither will idle as smoothly or as strong (although the low end cam picks up right away). IMO, you really should "need" one before you choose that as a modification.

The lifters aren't "lifters", just litle cups. If you're resourseful, you can get them up off of the cam several ways. If you're unbelievably crafty, you can back the tensioner off with the head and jug installed. If you're slightly crafty, and willing to buy an allen wrench that you probably don't have, and a screwdriver that you just might have, you need only remove the head, but not the jug, although experience dictates that releasing tension off of the base gasket, even though it isn't "disturbed", will probably leave you with a damp oil ring around it. (no drips, just a "weep". You will need to take the front cover off, and the primary (centrifugal) clutch. A penny (NEVER silver coins) in the primary drive gears makes a good holder, a two or three jaw puller takes the clutch off nicely (it's snug, buy not like some other stuff in there). A factory service manual would be your best friend, and a torque wrench would be a close second. Given the service manual, it's easily doable by a better than average DIY, learnable by any mechanically inclined person, and doesn't <require> a professional mechanic, although it is genuine motor work, not just "tinkering". You won't slap it out in a hour for sure. Plan on a couple of nights, and several beer runs if you havn't done one before.

[TechForeman]

Jake this place would be dead if it werent for you.

[Badtothebone400]

if you want to beat him find a hole with a nice amount of water so that it will be over his belt snorkle and he'll get his belt wet and will go no where lol then you can beat him just for the soul feeling of wining lol

[redstroke]

Jake thanks for the info I will post over on my thread.