By syff_uf on Unrecorded Date: Edit

howdy all,

on a light weight unit such as a maxII (670 lbs) how much the operator weighs matters. assuming 630 square inches of contact on the 6 tires lets do some figuring:

Ken Valentine = 450 lbs + 670 lbs = 1120 lbs, divide by 630 = 1.78 psi.

Dave = 270 lbs + 670 lbs = 940 lbs, divide by 630 = 1.49 psi.

Brandon = 110 lbs + 670 lbs = 780 lbs, divide by 630 = 1.24 psi.

the bottom line is that on vehicles that weigh so little (which is pretty much mandatory) the weight of the operator does have bearing on PSI.

surface area (tire contact) also matters. i've got a question... which one of the guys above runs his tires at extremely low psi (aka increased surface area) AND rarely gets stuck?... SEE, maybe brandon can make it through the nam mud.

moral of the story: put down that twinkie ! or you'll never get through that mud pit damnit.

~phil~

By MaxRules (Brandon_price) on Unrecorded Date: Edit

Good message Phil. Weight really makes a big difference. I could go even more places in the Max IV with 26" tires:

110 + 770 = 880, divide by 1110 = 0.79 psi

That is some LOW ground pressure! I really need a new Max IV...

The times that I do get stuck, it is almost always because the 14hp engine is not enough to move the machine like I need it to. Not enough accelleration and/or wheel spin when I need it. I nail the throttle to get that last bit of momentum needed to make it through the mud pit when all I hear is the wimply little engine bogging down and losing speed. I'm tired of that and this is what I'm going to do about it:
This weekend the engine is getting bored out. It will probably be bored .030 over. I will also be doing other mods to get more speed. The governor will be adjusted to 4500 rpm. Maybe a different air filter set up. I will also make dual strait pipes. It needs a small amount of back pressure but the muffler and factory exhaust set up just robs too much power. I'm tired of playing with a toy!

MaxRules

By mr. tinker on Unrecorded Date: Edit

brandon, there is a old saying about making more power.there is no replacement for displacement.

By hustler on Unrecorded Date: Edit

Great thought Phil. But I think you have something wrong. I don't think Brandon weight is 110 unless you talking about him being wet and muddy. I think he is only about 90#'s dry.

By JTBarleman on Unrecorded Date: Edit

Hey ... Max Rules ... since you're tired of "toys" ... a rice rancer buddy of mine in Sacramento has the perfect EIGHT wheel mud machine for you! A full size JD TRACTOR with front & rear duals. (Grin)
JT.

By Jim Marietta on Unrecorded Date: Edit

I have been thinking of purchasing/installing six additional tires to my 1999 22" rawhide tires 18 hp max II, to help alleviate getting stuck in the river bottoms muck. Is it worth the investment? The track are just to expensive.Are there other alternatives? Will appreciate everyones input. Jim

By syff_uf on Unrecorded Date: Edit

hmm...

if you weigh 270 and use tracks (1740 square inches) in a max IV it comes out to 0.60 psi… so you can eat all the twinkies you want but it’ll cost $2600 in tracks to best Brandon. well, maybe not… to best him you’d also have to lose the chicken genes… you know, the ones that while you’re going down a steep hill cause you to lock up the breaks while visions of your life pass before you… meanwhile Brandon is giving it the gas. LOL

i agree with mr tinker that there is no replacement for displacement… within reason… dropping a 440 mopar in your max IV would probably result in going 100 mph, bending the frame, shearing the tires off, breaking all the chains, frying the T-20, and burning the HDPE body to the ground… all within 15 seconds. it’d make a good video though.

back to business: the problem it seems you’re having Brandon is not just a strick horsepower one per se… a 14hp engine is enough to spin your wheels * provided * the gearing is proper. It’s too bad the max doesn’t have a two speed forward gearbox that you can shift while moving. The reason they don’t is that type transmission is both heavy and expensive. question: with your terrajet in low gear (i know it's slow) did it ever get bogged down in mud? my guess is that it didn’t.

~phil~

btw those mods you spoke of are pretty sound advice… the better the oxygen flow the more power. You may want to get the thing ported also.

By MaxRules (Brandon_price) on Unrecorded Date: Edit

Jim - Dual wheels would probably take you anywhere you needed to go. You need the axle bearing extensions, dual wheel adapters, and six new tires and rims. That is less cost than tracks but still a good pile of cash. I am told you have to ask RI for the dual wheel adapters because they are no longer advertised. They are too hard on the axles and drivetrain. Dual wheels are a big load on all of the machine.

I began taking apart my Max engine last night. The first thing I noticed is that it is way to cold out there in the shed! Tomorrow I am taking the engine out and bringing it in the house.
It is made a little different than I first thought. On most all motorcycle and ATV engines I have worked on, the cylinder and head come off separate from the block. On this type you would simply slide the cylinder off the piston while the piston is still attached to the crank. Once I got the Briggs stripped down I can see the cylinders are part of the block. This means the entire engine must come apart. Not a big deal, but different then I had planned. I will take pictures of the engine as I take it apart for everyone to see.

I was talking to some guys that race Briggs engines in karts. There are more mods for these engines than I ever thought there could be. It just depends on how much money you want to spend. With only a few mods I can run this engine SAFELY at 6000 RPM! It is going to be bored .060 over and depending on the cost, I may even have the stroke increased. Lots of CCs are gained from that. If I really feel like dishing out all my money, I can buy twin carbs. With those mods I could pass just about every quad on the trails. My Max would be uncontrolably fast... and that's how I like it!

When I bought a Max I never thought I would be challenging quads to a race!

MaxRules