By MaxRules (Brandon_price) on Unrecorded Date: Edit

I have decided to do some fun modification to my Max. The Briggs engine is great for quite operation and low speed power but I plan to buy a high rev 2-stroke for when I get the need for speed. I have found someone with a Rotax 454 two stroke two cylinder racing engine. It was raced only a few times and has some race modified parts (pistons, head). This engine should give me speed in excess of 70mph. I mostly want it for mudding so I can clean off the mud with fast spining tires when they get slicked off. I will also be able to climb steep hills that are very tall (I can only climb shorter steep hills with the Briggs because it runs out of power). I am talking about hills 80 degrees + were you have to go fast and use momentum to get to the top. The 4x4 ATVs have no advantages over a 70mph amphibious ATV!

MaxRules

By shelzac on Unrecorded Date: Edit

Brandon,
Make sure your insurance is all paid up.

By MaxRules (Brandon_price) on Unrecorded Date: Edit

He wants $435 for the engine. I will probably buy it if it runs good and I can get a good deal. I will rarely use the top speed but I am sure I can handle it on a long smooth surface. I will be able to take any hill and be even better in the mud. High speed will also greatly improve performance on sand hills or other loose terrain.

No need for insurance... I wonder if it is better to be thrown out or stay belted in...?

MaxRules

By John on Unrecorded Date: Edit

With a good roll cage it is better to stay belted
in.

By Bill H. on Unrecorded Date: Edit

The boys gona kill himself

By Phil Herrold on Unrecorded Date: Edit

Be sure to tell us how it goes when you get done. If it works you'll have lots of fun going 70 mph while the quad rider's jaw drops open and he's in your dust. That should show them.

By MaxRules (Brandon_price) on Unrecorded Date: Edit

I have been checking out some specs on the Rotax. In it's stock form, the torque is equal to the 20hp Kohler. Being a two stroke two cylinder reving 7000 RPM, it is built for speed. The racing mods should give it even more power and speed.

I don't plan to change anything except to simply swap out the engines. I will get a new Dayco belt because the original belt is glazed and ready to blow off. I can do 30mph with 14hp so with 50hp+ I don't think 70mph is too far out of reach.
The races will come back!

MaxRules

By Ken Valentine (Trackster1) on Unrecorded Date: Edit

Just try to keep all 6 wheels on the ground.
RIDE ON!!!!!

By magnum on Unrecorded Date: Edit

Brandon, what happens if a chain breaks and locks up one side of the wheels at 60 or 70 mph? I wonder how many times you will roll over sideways. 80 degree hills!? You'll roll over backwards! Max's do need more speed for mud and hills, but I think 70 is a little much. You should try ramping into water that fast, the wheels would probably rip off and you would end up in the water. ha ha. be careful. have fun.

By Marc Stobinski on Unrecorded Date: Edit

Brandon: If you want to go that fast, build yourself a roll cage and add a full racing belt/harness. You should also add a better seat to keep your body in position to maintain control at speed in the rough. I raced AATV’s in the 70’s and any flip over 30 mph was bad on both the machine and your neck. I assume you wear a helmet. If you keep the bench seat at least use a helmet and a neck collar the type karters wear. It may keep you from breaking your neck. Breaking a chain at speed usually puts holes in the lower hull when it jams. Make sure the master link clips are facing the right direction (open end back). Get to know your machine handling gradually before you go too fast You may also want to do some torque converter work and change your final gear ratio. Snowmobile racing engines and converters are designed for less weight. Without the right gears ratio your unit may be a dog going up hills. Good luck and have fun.

By Big Bob Bonberant on Unrecorded Date: Edit

Everyone needs to see the ATTEX doing wheelies in the racing videos that richard sells?

That is so cool, i guess we really miss a lot by not having real horsepower these days.

Everone can talk about big 25 hp engines today, put to see real PERFORMANCE you must go back to the snowmobile engines, sure they were noisy and unrealiable but they sure made you grin.

See you

Bob Bonberant

By Pat Miller on Unrecorded Date: Edit

Bob,
Check out the Land Tamer at www.landtamer.com to see the highest horsepower and performance in production today for a recreational class 6x6 or 8x8 AATV. With 80 hp 4 cylinder, it will blow the doors off any of the other AATVs with 16-25 hp lawnmower engines they put in those plastic machines. The new 8x8 Land Tamer is now shown on our website. Once you drive the Land Tamer you will think the rest are just play toys.

By Kyle L.Vogt (Cmdrvogt) on Unrecorded Date: Edit

Where can I find info on new/used 2 stroke engines,I currently ride a Honda Pilot(400cc.2stroke),top speed 67 mph,easily handles 6 ft of air w / no discomfort to your back,however it doe`nt float! I`m looking for a used 2 stroke 6x6. I preffer working on 2 strokes and have built several hi-perf engines(all Hondas). Let me know, Kyle

By MaxRules (Brandon_price) on Unrecorded Date: Edit

I am still looking for a 2-stroke engine. The Rotax I was wanted was liquid cooled and did not have electric start. I found another engine that is a 484cc that was once in a 6x6 so it already has the electric start, exaust, and clutch.

Pat Miller I do like your Land Tamer but you can't look down on "plastic ATVs with lawn mower engines". Belt drive has been used for over 50 years and the engines have long lasting dependable lives. As for the plastic, there is simply nothing better. Light weight, doesn't rust, doesn't need painted, and won't dent. I saw a Honda quad crash into an Argo Bigfoot over the weekend. The Honda racks and bumper were all bent up and the headlights were out of place. And the Argo? Not a single scratch!
We all tend to run into something once in a while. Trees or another ATV, something is always in the way. I have hit a few trees and a few quads and I like the idea of knowing that nothing on my machine is bent or damaged.

If you really want to impress us, bring back the Attex!

MaxRules

By Cmndrvogt on Unrecorded Date: Edit

Anybody got a good hi-performance 2 stroke engine for sale, say arround 850 cc or bigger. I wonder if you could fit a small automobile engine in one ? Just kidding , however I would like to find a powerfull engine. Kyle Ps. any riders in east TN. ?

By JT Barleman (Namelrab) on Unrecorded Date: Edit

Brandon ...RE TWO STROKES. I don't know where you live ... but ... check the snowmobile junk yards. They usually have just about ANY size and make of two stroke that was ever manufactured for a snowmobile ... INCLUDING ... some really huge machines. Don't know if your 6x6 will float after putting a really big two stroke in it ... but then again ... why float when you can fly?
JT (ATTEX 400 Chief with a Rockwell JLO 399cc)

By Marc Stobinski (Jerseybigfoot) on Unrecorded Date: Edit

Check out the following pages for snowmobile engines. Dans snowmobile and atv salvage prices were a bit high on newer engines. He wanted $900 for a 500cc twin with carb, exhaust and clutch.
http://www.danssalvage.simplenet.com/snowmobile.html
http://www.alssnowmo.com/alssnowmobile.html

By mr scrambler on Unrecorded Date: Edit

A friend of mine just restored a Big Max with a kohler 440 2-stroke. It came this way from RI and it even says it on the data plate. I think its too fast for me but it will fly. It has been clocked at close to 50mph by the previous owner.
I'll let you know how it does on the steep hills, I know it will do good in the mud with the high wheel speed. Also if you have a roll bar please use seat belts so you don't get caught between the ground and the roll bar. I'll keep you posted on the 2-stroke power.

By virusdog on Unrecorded Date: Edit

I just got in to aatvs two monthes ago when I bought a Max II with a kawasaki 440 two stroke and it hauls ass. Once you go two stroke you can't go back. It's so thrilling, that you will have no problem dealing with the higher maintance associated with two strokes. All you guys should go for it, It's worth it! TWO STROKES RULE

By david berger (Davidrrrd) on Unrecorded Date: Edit

virusdog, dont you mean 2-cycles rule & 4-cycles drool !!

By roadwolf on Unrecorded Date: Edit

hey mates, i think robert burns said it best, "you can never go back" .

By VIRUSDOG on Unrecorded Date: Edit

HAS ANYONE TRYED AN EXPANSION CHAMBER FROM A SNOWMOBILE ON THEIR TWO STROKE? I THINK IT WOULD MAKE A BIG DIFFERENCE

By MoralDK on Unrecorded Date: Edit

Yes, per my post about the 440 max with no low-end. Expansion chambers are designed to provide the optimum back pressure to meet your engine's operation needs. Typically, more back pressure will aid the high-end performance and vice-versa. However, it is a long shot to be able to grab any EC and expect it to work on your engine. They're tuned to a particular engine and for particular performance that may or may not meet your needs. I think I was lucky to find a shop that had the various pipes for a 440 cc. It's even more rare to find any that will physically fit in the machine. A 440 cc 2-stroke with a straight pipe is really a bad choice and won't offer much increase (if any) in performance over a 20 hp 4-stroke.

By Tim Wafer (Iflyrctoo) on Unrecorded Date: Edit

As long as we are talking two-stroke mufflers. The Tracker I bought has a CCW 400 two-stroke. I need to replace the muffler. Can anyone educate me in how to go about finding one with out a lot of trial and error? The one that was on it was about 11" long and oval in cross section about 4" x 8". God knows if it was correct for this engine. It was installed with standard automotive muffler pipe and clamps. Any one have any rules of thumb or even a detailed explanation on how to select a 2-stroke muffler?
Thanks
Tim

By ATV Master on Unrecorded Date: Edit

woohoo!! got the Max2 running!! How fast will this 1981 beast with a 14 yr old mint Tec 16 hp. go?? i have blackwaters on it. i think i hit 20 but the engine needs a tune up after sitting so long. this is not the original engine, i got it from a freind with an 86 max. how fats will it go on land and water after being tuned up?

By ATV Master on Unrecorded Date: Edit

and fully gunned throttle, the engine running top speed?

By MaxRules (Brandon_price) on Unrecorded Date: Edit

My need for speed has been cured. Today I bought a Hustler with 440cc 2-stroke and T-20 trans. I was idling down the driveway and nailed the throttle to see just what that 440 would do. It almost left me behind LOL. It took off like a rocket and threw a roost of gravel. I took it through the mud hole once and threw a good roost of mud onto the trees. Tomorrow I'll take it out and climb some hills to see how good the torque is. The tranny has two separate shift levers so I can put on side in forward and the other in reverse and do a spin. The tires are like new and are really good for mud. If all goes well I am taking both my Max and Hustler to the Deepwater ride on August 12-13. Can't wait to see how it goes through mud with fast spinning wheels.

Thanks to Richard for all the helpful information!

MaxRules

By maximus superious (Syff_uf) on Unrecorded Date: Edit

I need help shoe horning a keith black 426 hemi with a roots blower into a max II can anyone help ? can the T-20 take 3000 horses ? we'll see :p

By BILLY on Unrecorded Date: Edit

Superious Gluteus Maximus--

You're in luck, it just so happens that I just finished building such a vehicle. Actually, I put a 454 with 4 on the floor, 4 valve quadro jet intakes, with 6 way posi-traction, and dual plain manifolds. Not to mention the Vortex superchargers (8, one for every cylinder), 11 Turbos, two jet engines and a trash compactor (for the beer cans).

To answer you intelligent inquiry, YES, the T-20 has shown no problem handling the 8,000 HP in my Max IV (the family weekend vehicle). It's now turning over the 1 Million mile mark on the odometer.
I put the extra miles on it delivering the mail.

Please let my omniscient mechanical knowledge be a help to you in the future.

BILLY

By syff_uf on Unrecorded Date: Edit

ok ok my REAL question on the subject of SPEED... has anyone pondered taking a MAX II or IV and putting in one or two bucket seats with 5 point harnesses AND creating a real rollcage ? that seems like a good idea if you're going to be going fast. might not be a bad idea even if you're not going fast. if RI or ODG would make a vehicle like this it could open up a whole new market. imagine an amphibious vehicle as fast as a 4x4 and much safer... driven more like a go cart. any thoughts ?

~phil~

ps BILLY that sounds like a frame bender there... er, frame melter :p

By Marc Stobinski (Jerseybigfoot) on Unrecorded Date: Edit

Been there, done that 30 years ago. The big problem is ripping the bottom out of body from rocks. 6x6's bounce too much and will land hard. You would have to have some serious skid plates,oversize axles reinforced frame, etc to last. If any one is interested in putting a 6x6 motocross event together let me know. I can post the old NATVA race rules so you can get an idea how it was done 30 years ago. If there is enough interest perhaps an event could be held at an ORV park with a track.

By Atex Bob on Unrecorded Date: Edit

Syff_uf: It's already been done: It's called an Attex super chief!!!!!! Look at all the racing records and see what brand has won 99% of all races.

By BILLY on Unrecorded Date: Edit

Mark;

I think that is a great idea! I can just see it now on ESPN 2!

An all new era for the AATV races to return to, especially with the new technology, horse power, sponsors, mud pits, obsticals, and groupies!!!!

It would be a lot like the swamp buggie races, but for the modified amphibs.

Someone out there better put this thing together!!!

BILLY :-)>

By syff_uf on Unrecorded Date: Edit

hi everyone,

thanks for the responses.

(Marc) what type of safety requirements did NATVA impose ? racing on mud or sand sounds like a better way to go to keep the machines from getting too broken. i was interested in vehicle modification more than anything; the feel of a machine is important. i would like to see a current production machine that is 6x6 on bottom and go-kart like (harness/cage/seated with feet straight) on top.

(Atex Bob) thanks for the information... i looked at the machines and they gave me ideas for a roll cage. could a Max II be altered to be more like the seating in the Attex ? is the Attex seat lower down in the unit ? it's hard to tell from the pictures. a Max IV could be altered to produce what i'm looking for... not sure about the II's (not be enough room).

~phil~

ps billy... if you want to get the rest of the board interested in racing... tell us more about those groupies hehe :p

By Marc Stobinski (Jerseybigfoot) on Unrecorded Date: Edit

syff_uf,
NATVA required roll bars attached to the frame, fire extinguishers, helmets, steel torque converter shields, shoulder harness,and seat belts. Most of the modified machines had lowered seats. Some even repositioned the engine for better balance. The Attex machines dominated races after the first couple of years with their factory built ready to race machines. There was also a 500 cc limit on 2 stroke engines. 4 stroke machines used a handicap formula. It would be interesting to see the new 4 stroke V engines compete today. I understand that they are doubling the HP with the new engines with various mods. I wonder what a unmuffled modified Kohler Command sounds like at 7000 rpm .

By syff_uf on Unrecorded Date: Edit

Marc,

thanks for the information ! i tried to post a reply several times this week but it never went through :(. the attex sounds like what i need to learn more about. i might just order me that manual from route 6x6.

i would like to build a machine. my brother was a part of mini-baja (while becoming a mechanical engineer) and raced karts. the carts used a yamaha KT100 18hp 100cc motor. it idled at 6500 rpms, the clutch engaged at 10,500 rpm and my brother would run it to about 14,200 rpm... 67 mph average speed in a 220-285 lb machine must be incredible... he's had it going 132 mph on the straights. this was in his young and crazier years... i am sure he can help me make a 25 mph 6x6 hehe.

he wanted to race these carts that are 125cc with a six speed gearbox... they'll do 0-60 in 2.7 seconds... now *thats* flying.

~phil~

ps when i was a kid 7 grand in a Briggs & Stratton would sound like a connecting rod trying to go through an engine block... hehe, they don't even have enough torque to blow up right ;)

By Argofun on Unrecorded Date: Edit

Do headers make 6x6 faster and more powerful? if so how much and where do you get 1 and are they worth it? are they hard to install or not.Thanks

By Dave on Unrecorded Date: Edit

That 454 that your talking about more than likely came from a blizzard 9500+.Chances are it's too much moter for your max.For starters,it came from the factory with twin tuned pipes,how will you make them fit?A4 stroke will run with a strightpipe,a 2stroke MUST have a tuned pipe or pipes made for that moter.If not.Best case,won't run.worst case,it will melt.This is high strung liquid cooled 2 stroke a rad won't work.You would have to use external exchangers[they don't like rocks].They will work great in snow or a pond but thats it.I doubt that your stock drivetrian[ converter,transmission,driven,chains and sprocets]will handle 0 to 7000in 50ft but good luck trying Dave

By peter gruessing (Pete6x6) on Unrecorded Date: Edit

I'm currently building a 6x6 from scratch and I think I'm going to use a snowmobile engine and torque converter for a powerplant. Any suggestions?

By carmen cafro virusdog on Unrecorded Date: Edit

Exelent choice Pete. I own an old max with a kawasaki 440 two stroke and I love it. It has the most thrilling power. I wish it was water cooled but my next max project will be a brand new max 4 that I will swap it's slug 4 stroke eng for the largest watercooled 2 stroke that I can find from a snowmobile.

By pete6x6 on Unrecorded Date: Edit

Virusdog,

Yes I would tend to agree on that. The two stroke powered 6x6 machines seem to perform much better. I'm just having a hard time gettign my hands on a reputable snowmobile engine dealer. I'm assuming the make watercooled two stroke engines for snowmobiles now right? What is the biggest two stroke there ever made for a snowmobile anywpays?

By Daron on Unrecorded Date: Edit

The other day,I found a water cooled 440 Kawasaki.It is in a snowmobile now.I can get it for $100.... but would it work in a Max11?The snowmobile has a radiator,and also a heat sink under the seat.Where to put the radiator,and could I do without the heat sink?Any replies are welcome.

By E L McKenney on Unrecorded Date: Edit

I too have been looking at replacing my 484cc air
cooled with a h20 version. If the exhaust fits, a
radiator can be placed horizontally using an
electric can for cooling