Start to my lt1000 4x4 Mud Mower

Recently I acquired an all wheel steer mower that was beyond repair, however the rear steer transaxle was fully operational so I dropped it with the thought of putting it up front and making a 4x4 mud mower. At the moment the steering isn't hooked up but I've cut out a bracket that will wrap around the steering knuckle and allow it to steer. Based on what I've seen other people do, this is a first and requires no modification of the original steering linkage. I plan to upgrade the opposed twin motor a little(alot) meaning billet flywheel & connecting rods as well as equipping 2x 28mm flat slide mikuni to it, thinking of putting a amr 300 supercharger on it? any thoughts? (odviously id be geting rid of the transaxles when i hop up the motor)( this is update 1)

Welcome to ATLTF!  Sounds like you got a fun build going on there!

4x4 lawn tractor is really cool, I actually had this same idea a couple months ago, why would you want to rip the axles out when you drop the built oppy in?

TechnoChicken wrote:

4x4 lawn tractor is really cool, I actually had this same idea a couple months ago, why would you want to rip the axles out when you drop the built oppy in?

because the transaxles are only rated for around 35 hp and this will be making around 50ish hp

Sounds like a good build plan and I like your idea of making a wrap around steering linkage, I hope it works out as planned!

It's not just about how much power you have, it's how you use it... guys blow up stronger diffs than those with only 10-12hp! Lol. What in the heck are you going to do with 50hp on a mower that you can't do with 25 for a tenth of the price? I bet it would cost upwards if 5 grand to build that to have it hold together and by then there's no original engine left anyhow except for maybe valve covers and engine tins...

Ive got another all wheel steer axle mabye 4x4 4ws?

JittyJat wrote:

TechnoChicken wrote:

4x4 lawn tractor is really cool, I actually had this same idea a couple months ago, why would you want to rip the axles out when you drop the built oppy in?

because the transaxles are only rated for around 35 hp and this will be making around 50ish hp

, meh, who care honestly, just don't pull to many wheelies, what would be the weakest links of those axles? Would there be a way to make them better?

Budget_gokart wrote:

Ive got another all wheel steer axle maybe 4x4 4ws?

I thought about that but for me it just isn’t worth it as eventually when i do hop up the motor I'm gona have to rid the transaxles

TechnoChicken wrote:

JittyJat wrote:

TechnoChicken wrote:

4x4 lawn tractor is really cool, I actually had this same idea a couple months ago, why would you want to rip the axles out when you drop the built oppy in?

because the transaxles are only rated for around 35 hp and this will be making around 50ish hp

, meh, who care honestly, just don't pull to many wheelies, what would be the weakest links of those axles? Would there be a way to make them better?

Not that i know, and the weakest point would be the actual gears you'd shift in and out of the gears eventually just strip there teeth off with that many ponies

Cool project.

Are you planning on keeping the 4WD parts and just taking out the trans axles after modding the engine?

How much does it cost to hop up an opposed twin engine? I'm just curious.

FatMike wrote:

Cool project.

Are you planning on keeping the 4WD parts and just taking out the trans axles after modding the engine?

How much does it cost to hop up an opposed twin engine?  I'm just curious.

From what i have preordered at the moment around 1300$ but im also supercharging it so 250$ comes from that, otherwise its the stainless valves, billet rods and flywheel, reinforced shaved heads, hotter plugs, and the 2x 28mm Mikuni flatside carbs. On top of that im having the block reinforced and thats around 300$ so for what im doing it’s expensive but if you wanted to ad the bare minimum to rev to 5 grand it may cost around 800$

Thats not to bad i was thinking it would cost more than that.

To answer some unanswered questions/statements here. The amount of power is not what kills your trans… like Brainator said, it’s what you use it for. In my own words I would say more like how you drive it. If you’re speeding through the woods and catching air and landing hard you’re bound to split your diff whether it’s locked or not. Only thing that would help that is braces. The other thing is not so much the teeth on the gears as it is the shift keys. They just are not going to hold up to that kind of power. Even 25 HP is pushing it. I’m sure there’s ways to make it work and keep it more ‘original’ like I would do and use the transaxles, but it’s his build and probably less complicated and more reliable the way he’s planning on doing it even though he hasn’t mentioned it yet.

@Brainator, yes 50 HP is a lot and he could probably do just as much with 35. But there is no way it will cost $5k. $2500 may be more realistic unless he just has a wad of cash burning a hole in his pocket and feels like doing anything and everything he can to it. And oppys really can handle a LOT of power. Yeah he’ll need all new internals just as any other engine would need, but the block can probably handle a good 50 HP. Don’t know about the crank but even to push 30 you usually will need all new internals.

Sorry if that comes across rude to anyone in anyway lol it’s not meant to be. Just felt the need to clear some things up.

And ya got a nice start there man! I eventually plan on doing a 4x4 with a built motor myself but I aint up to it yet. Definitely will be watching this one!

Murraymountain wrote:

To answer some unanswered questions/statements here. The amount of power is not what kills your trans… like Brainator said, it’s what you use it for. In my own words I would say more like how you drive it. If you’re speeding through the woods and catching air and landing hard you’re bound to split your diff whether it’s locked or not. Only thing that would help that is braces. The other thing is not so much the teeth on the gears as it is the shift keys. They just are not going to hold up to that kind of power. Even 25 HP is pushing it. I’m sure there’s ways to make it work and keep it more ‘original’ like I would do and use the transaxles, but it’s his build and probably less complicated and more reliable the way he’s planning on doing it even though he hasn’t mentioned it yet.

@Brainator, yes 50 HP is a lot and he could probably do just as much with 35. But there is no way it will cost $5k. $2500 may be more realistic unless he just has a wad of cash burning a hole in his pocket and feels like doing anything and everything he can to it. And oppys really can handle a LOT of power. Yeah he’ll need all new internals just as any other engine would need, but the block can probably handle a good 50 HP. Don’t know about the crank but even to push 30 you usually will need all new internals.

Sorry if that comes across rude to anyone in anyway lol it’s not meant to be. Just felt the need to clear some things up.

And ya got a nice start there man! I eventually plan on doing a 4x4 with a built motor myself but I aint up to it yet. Definitely will be watching this one!

You are absolutely right, it's his build, honestly his choice I was just curious as to why you want to drop the axles, makes a little more sense to me now, I personally on weigh about >130 lbs so breaking axles is no worry of mine, however, the trans I destroyed was done when I tried to remove the rusted pulley without pulling the trans, used a torch and a pickle fork, destroyed the C-clip on the input shaft, and the gear being wedged against the case put a hole in it.

Murraymountain wrote:

To answer some unanswered questions/statements here. The amount of power is not what kills your trans… like Brainator said, it’s what you use it for. In my own words I would say more like how you drive it. If you’re speeding through the woods and catching air and landing hard you’re bound to split your diff whether it’s locked or not. Only thing that would help that is braces. The other thing is not so much the teeth on the gears as it is the shift keys. They just are not going to hold up to that kind of power. Even 25 HP is pushing it. I’m sure there’s ways to make it work and keep it more ‘original’ like I would do and use the transaxles, but it’s his build and probably less complicated and more reliable the way he’s planning on doing it even though he hasn’t mentioned it yet.

@Brainator, yes 50 HP is a lot and he could probably do just as much with 35. But there is no way it will cost $5k. $2500 may be more realistic unless he just has a wad of cash burning a hole in his pocket and feels like doing anything and everything he can to it. And oppys really can handle a LOT of power. Yeah he’ll need all new internals just as any other engine would need, but the block can probably handle a good 50 HP. Don’t know about the crank but even to push 30 you usually will need all new internals.

Sorry if that comes across rude to anyone in anyway lol it’s not meant to be. Just felt the need to clear some things up.

And ya got a nice start there man! I eventually plan on doing a 4x4 with a built motor myself but I aint up to it yet. Definitely will be watching this one!

yea thanks, you definitely did a better job at explaining that than i did i don't plan to drive it that hard (no jumps or speeding in the woods) the transaxles are just meant to be temporary whether they break or not is another story. for people wondering i'm setting it up so powerful at the moment because if this tractor ever outlives its use (major breakage) i want to be able to either turn this engine into a horizontal shaft or take the parts off of this engine in the pic and put them on a horizontal shaft briggs oppy then stick it on a future kart project. But most likely I would just fix any major breakage. About the cost this is what i have at the moment this is what i have going into it,
-billet flywheel & billet rods:$708.03
- Blue Fuel line, fuel shut off valve, brass y nipple, 2x Mikuni 28mm flat slide, 2x Blue 45mm air filter, Adapter rubber Inlet Intake, extra cam (Just in case),Splitter throttle cable: $232.59
-misc.(such as pipe for headers, intake,fuel filter, induction tubing,hotter plugs, etc):$304.78
- idk if im doing a supercharger or not but this is the cost: $256.68
-So in total without the supercharger i'd be putting $1245.40 give or take
-With the supercharger it would cost: $1502.08
Most likely the supper charger wont go be put on unless i decide otherwise after i've built this, However that being said where i live they do have a annual mud mower race, well hasn't been going scence corvid hit but they have announced they will be starting it back up next year around september or october so i have about a year to get this done lol. And if anybody wonders why I'd spend this much money on it, my reason is 5 words… For the hell of it

Well we all do stuff for the hell of it so have at er! Lol.

What about the crankshaft? I'd be surprised if a stock one could handle much more than double the power plus the added compression and same for the pistons, to run 50hp you'll have to run alky or ethanol no? Whatever you do please, PLEASE build one hellava scatter shield and a firewall! Even at stock and just above stock power things can go bad FAST! At the power levels you're talking about you could end up with a giant frag grenade!

With that said.. I'm excited to see it built, don't think I'm hating on you! Lol

Brianator wrote:

Well we all do stuff for the hell of it so have at er! Lol.

What about the crankshaft? I'd be surprised if a stock one could handle much more than double the power plus the added compression and same for the pistons, to run 50hp you'll have to run alky or ethanol no? Whatever you do please, PLEASE build one hellava scatter shield and a firewall! Even at stock and just above stock power things can go bad FAST! At the power levels you're talking about you could end up with a giant frag grenade!

With that said.. I'm excited to see it built, don't think I'm hating on you! Lol

That i know, the crank should be able to hold up to the hp its not hollow like most b&s engines, i've dealt with hopping up predator 670cc engines before on my buddys cart and they are able to take that much power with the stock crank, in fact the cranks are almost identical if it wasn't for the fact that b&s ballences the cranks way better than predator that and the fact that one is for a v twin as opposed to an opposed lol. 50hp isnt that much of a strech if you think about it, im removing the govonor and safely doing this by adding the billet parts requred, and pumping way more fule mixture into the engine with the x2 28mm mikuni to the whole ordeal. i do plan on making some reinforcements to the fire wall  (just in case as when hopping up any engine) and because the stock hood wont fit on for the life of it i'll be beefing it up also by adding a custom hood if this, ALSO almost forgot i found a horizontal shaft oppy on craigslist the other day for 50$ and went and got it this morning, downside is it's a generator but i can separate the block from the generator so if i ever want to do a conversion it will be possible with relative ease. and i dont think that people are haiting they are just expressing their concerns which actually helps me alot so thanks!

Thanks for explaining man! I do look forward to see it being built and tearing up some dirt!

Any updates?  Im interested to see the engine build.

JittyJat wrote:

reinforced shaved heads, hotter plugs, and the 2x 28mm  Mikuni flatside carbs.

With higher compression, more fuel and more ignition advance, you will probably want to go with colder plugs.  A hot one in that application will likely promote spark knock but the engine will tell you what it needs when you start tuning on it. As a starting point in your tuning, i dont think going hotter than stock would be wise.  Very much more so if you boost it.  You would be better off with a higher powered ignition module / coil so you dont suffer from the spark getting blown out, though closing down your gap would probably help with that if you run the stock ignition.

Krawler86 wrote:

Any updates?  Im interested to see the engine build.

JittyJat wrote:

reinforced shaved heads, hotter plugs, and the 2x 28mm  Mikuni flatside carbs.

With higher compression, more fuel and more ignition advance, you will probably want to go with colder plugs.  A hot one in that application will likely promote spark knock.  Very much more so if you boost it.  You would be better off with a higher powered ignition module / coil so you dont suffer from the spark getting blown out, though closing down your gap would probably help with that if you run the stock ignition.

This topic has scene been closed and continued on
https://www.atltf.com/t6910-withdraw-22-bo-death-wish-4x4-lt-1000-mud-mower
However i do appreciate your subjections, but plans for the engine have also been revised and go as follows, higher compression on flatheads is more of a hindrance than an aid and as such airflow and static compression have become more of the priority, that being said hotter plugs would be of greater help and i no longer plan on supper charging it has that alone would add another grand on the upgrades. But i do still plan to add 2x 28mm Mikuni carburetors and all of the performance goodies (aka flywheel, connecting rods, and pistons) but due to a recent surgery ive had work on it has come to a hault and don’t plan on starting the project back up until 2023 if not 2024 as life for me has gotten quite hectic. But rest assured that im not going to let this project slip between the cracks as im so heavily invested into the concept and project.