Max iv diesel swap

[ARGOJIM]

Another avenue may be Max II axles.

[eawood]

Awesome job! Why did you move the T20 so far forward? I haven't put much thought into that next step, but in my head i imagined trying to match center to center distance with a standard size belt. Where did you scrounge up the reverse driven clutch? Re-molding the tub was my main holdup with going right to moving the T20 forward and dropping the d722 down.
One thought i had was to push the T20 forward 8-10 inches, just enough for the oil pan to clear. I like your layout it looks very well thought out As you can tell I'm still in the thinking stage. I got the engine for next to nothing so I wanted to get it together and see how it performed before I committed to tearing into the project.

[miller_time]

I ended up moving the t20 that far forward so i could run shorter chains to the center axles. I ended up using a john deere gator belt so they should be easy to get little expensive though but in. a pinch i can pick one up local. The clutch is off of a polaris indy 440. You can pick them up real cheap on ebay. If you run the 780 with the polaris secondary you shouldn't have to mold the tub at all. I am going to have mold the tub to clear my clutch but it should give me a little more overdrjve than a 780.

[eawood]

Great info. Thanks for the lead on the polaris clutches. Looks like with a shim and some tuning itll work great with the 780 drive clutch. Gator belt looks like the ticket for a long belt.

[miller_time]

Making some more progress. Rear seat mount almost done. It is now going to be 4" back from the original spot and i am going to move the front seat back 1". Gotta finish the seat back mounts, battery tray that will be built into the seat mount and hinges for the seat to flip up. Just about ready to put the frame into the tub. Hopefully the radiator will be big enough. I am not sure if it will be.

[hipowerone]

I have been following this thread for some time, not because I might be doing anything like this soon, but more for what might and could be done. In aviation a lot of emphasis is directed to weight and balance, and for good reason. In aviation, what might be considered a simple upgrade often triggers a full blown evaluation of the aircrafts new center of gravity and weight and balance charts. I cannot help but wonder what effect the swap to a diesel engine and its placement, along with repositioning the transmission, fuel storage, and seating, etc. might have on gross weight and balance. What effect does this conversion have on the total gross weight/carrying capacity? While not so critical on solid ground, though it may be, the effect on the unit in water would certainly be critical. Is it just me or is anyone else concerned? Any thoughts?

[miller_time]

The weight will only be a little more than a max iv 1050t with the liquid cooled kawasaki. I think the kubota only weighs like 30lbs more than the kawasaki. I looked it up when i started this project but don't remember the #'s off the top of my head. So with the engine, some extra steel, tires and bigger axles it will be around 100lbs heavier than a new max iv. So i am not concerned with the weight. Balance in water may be interesting but to me it seems the weight of the machine will be better balanced than before but we will see. I am not real concerned with that. On land however i think having a much lower center of gravity will be a good thing. Same with more passenger room. My wife is only 5'3" and complained about the leg room. I also think on the newer max's the rear seat is back 3" more from the factory than my older max. So my rear seat is only 1" farther back than a new max. So with the seats being back say 1" the tranny being moved forward and 30 extra pounds in the rear i think in the end the balance won't be a whole lot different.

[dirtdobber]

The weight will only be a little more than a max iv 1050t with the liquid cooled kawasaki

This really is an interesting thread. Like a previous post, I too thought balance/buoyancy would be an issue and was surprised by the small weight difference between the two engines. So surprised that I had to look it up for myself. The dry weight of the D722 engine is 139 pounds. A 25 horse liquid cooled Kawasaki engine is 122 pounds.

[miller_time]

I was surprised also. The only thing i am unsure of is if the weight of the kawasaki includes the radiator. Which i assume it does because it is mounted right on the engine. With the kubota i assume it doesnt count the radiator because its mounted separate. So i figured about another 5lbs for the radiator. So about a 22lb difference.

[dirtdobber]

if the weight of the kawasaki includes the radiator

Judging by the pictures I found, I assume the kawasaki weight includes the radiator and may even be a "wet" weight. The kubota will have the extra weight of the radiator, coolant, oil, radiator mount.....which still isn't a whole lot of difference. If it really mattered, you probably could lighten your engine just a bit by modifying the flywheel, taking a little out of the engine mounts (they look pretty robust), and maybe another place or two some changes could be made.

Cool project.

[miller_time]

Yup i agree i could cut some weight if a wanted. But i am not concerned with the little bit of extra weight right now. May change my mind after driving it though we will see. Got the muffler mounted today just need to make a support bracket for it. Also got the axle flanges welded on. Didn't have my phone will get picture ls later on.

[hipowerone]

It sounds like you put some thought into position and weight, so that is good. With a lower center of gravity, the unit should be more stable both on hard ground and in the water.

Normally I would not have chimed in, but when it comes to an AATV, the amphibious part really is a stickler. Some may not have noticed, but RI and MAX made a pretty good deal of "weight" when they printed the owner manual specifications on pp 54-55. They list the dry GROSS VEHICLE WEIGHT and the GROSS PERMISSIBLE WEIGHT IN WATER, and then go on to list accessory weights.

There is a definite reason for this. If you take the dry vehicle weight and then add liquids, and any changes in attached basic equipment (tires/wheels) and add all additional accessories, you will find that your maximum permissible load drops. First and foremost, how much fuel are you carrying? Gasoline is approximately 6 lbs per gallon, so just having a full fuel tank eats 30 lbs of your maximum permissible load weight. In water your maximum load is about 500 lbs for a MAX II and that is with no accessories or fuel. If you have a larger engine, tracks, winch, winch plate, windshield, roll bar and full fuel; your original on land 2 x 250 lbs passenger dry MAX II is now a wet 1 x 162 lb passenger MAX II in water! While you may be able to "load more", you seriously run the risk of making your AATV more unstable in water and you will quickly exceed the maximum water displacement and sink your toy! My neighbor learned this the hard way back in the 70's when he sank his newly acquired COOT trying to cross a small body of water with 4 persons on board.

[miller_time]

I think without looking at my manual max iv load capacity in water is only 500lbs less accessories. So with 2 men and a roll cage you are possibly overloaded in the water. I am not planning to run it in the water much but want it to be capable of doing so if i need to. With the roughly 100lbs i will add i should be ok with me and my oldest son. Pa is a pain it must be registered as a boat to take it in any water other than a private pond and its a real pain if not impossible to register an aatv as a boat in pa. So water time will be minimal if at all

[miller_time]

Have me more curious now. I think i will put it on the race car scales when done so i know for sure how much it weighs.

[hipowerone]

That makes a lot of sense. From an aviation point of view, doing a weight and balance before each flight, makes perfect sense. Depending upon what you load for gear, and who is riding, with an AATV it more sense before attempting any venture into water. No one could ever fault you for being careful.