MTD Varidrive Pulley Swap?

Hello all, I'm new here and new to small engines and modding mowers..

I want to pulley swap my late 90s MTD Lawn Machine (varidrive). What's the best method for someone who doesn't have access to a welder, torches and so on..
Can I just buy an engine pulley that'll bolt on?

And is okay to pulley swap a varidrive? Most I've seen are just standard 4-6 speed transmission. Not sure if it matters. But figured it was worth asking.

I'm not looking to do 100 mph. Just enough to make it slightly faster. Maybe 15mph, give or take. Any advice will help. Thanks.

This video by Fearlessfront should get you in the right direction:

https://www.youtube.com/watch?v=pk34jusEJbA&list=PLwHEbMbV0VrukdDp1OmfCGkVdcW9kOXV2&index=7&scrlybrkr=1455db64

From what I understand, the MTD chassis are fairly weak and you will have issues with the varidrive eventually. They just aren't built very well. I have one for mowing and it's really complicated under there. It would definitely work for now, but I'd start looking for another mower, or parts to gut the vari-drive and convert to an MST or peerless 900 series. Just my 2⍧

Thanks for the info. Kind of a bummer.
I'm not really planning on romping it to hard. Just slightly faster and some better tires. It's more of a cruiser than an “ATV". I will hit some mud holes, but nothing to crazy.

I could look for another, but this one was given to me for free by a neighbor. All it needed was a tune up. So it's kind of convenient for me to use this. Especially since storage space is kind of limited.

Yeah. It should work and drive fine, I just dont know how well it'll hold up. since it has a lot of right angle bends, I would think you could weld some angle iron to all of the joints/bends in the frame. I thought about building one, but the one I was looking at had a hydro and it was too much work to be what I wanted, so we used it as parts. I'm using the hood and side panels from it on the CQ

My mtd back when it had the vari drive it took me a while to figure out how it works.

This really helps out: https://www.atltf.com/t3364-mtd-trans-matic-vari-drive-shift-on-the-go-demo?highlight=vari+drive

I believe thats most likely your setup? They came with a diff design as it got newer.

The front pulley is easier in your application to swap, as you can buy 1" keyed pulleys at desired size with no welding/cutting required. Only problem is the belt has to be a "perfect" size from the demo video. Could be 1/2" less than what is needed and wont expand on the variable pulley like it should and not get full speed, if that makes sense.

Those vari-drive pulley setups run a 5/8 inch wide belts to make them work right too. I did a trans swap on my mower that cuts the grass so I can go slower actually.I got 36 forward gears and 6 reverse gears. I pulled the f/n/r trans and put a 6 speed in. and went from a 8 inch pulley to a 4 inch pulley on the trans. The original 8 inch pulley had the groove for a 5/8 inch belt, when swapped, the 4 inch pulley has a 1/2 inch groove so the belt rides just a little outside of the pulley. Also reused the original 5/8 belt because it was just impossible to find a new 5/8 belt of any size, anywhere. To make the original belt work, I just placed a couple fixed idler pulleys in a couple places to take up the slack. I also added a simple shifter under the seat for the transaxle. Then readjusted the foot pedal clutch linkage to get it working right.

If you replace one of the belts with a 1/2 inch wide belt, you'll only get like 2/3 of the gears on the shifter, maybe.

How the belts work is- you have a trans belt and an engine belt. The trans belt has a spring loaded idler and stays loaded with pressure on the belt all the time. The engine belt has the actual clutch on it. How it works is the double pulley, is the point where the belts over lap each other and is where you get the different ratios of so called gears on the shifter from. The double pulley position of it in neutral with the clutch pressed, is the trans pulley, on that double pulley in the position of where the belt is all the way on the inner part of the pulley, while the engine belt on this double pulley is in the neutral position where the groove is all the way closed and the belt is all the way on the outer part of the groove with a little slack for neutral. This should be your starting point for any kind of pulley swap. When clutch is let go, the double pulley swings back I think, and both belts make contact. How much the double pulley swings determines the gear. You'll notice the clutch pedal will go back further, the higher the gear. You can control the mower speed just by using your foot on the clutch pedal by having the shifter in the highest gear and while in neutral, let off the clutch pedal slowly little by little, then push the clutch pedal in a little. This is actually how a torque converter clutch works.

The down side is that it takes time to go through the gears when in ,say 6th gear and you dump the clutch, it will take some time to actually get it in 6th gear since the belts have to change ratios from 1st gear all the way to 6th gear.

Thanks for the help everyone. From what it seems, it seems like varidrives aren't really a favorite around here. Lol.
I don't know much about them or normal 6 speeds. But I don't see mechanically why it wouldn't work. Idk. I'm a beginner in this kind of stuff.

freebird wrote:

Thanks for the help everyone. From what it seems, it seems like varidrives aren't really a favorite around here. Lol.
I don't know much about them or normal 6 speeds. But I don't see mechanically why it wouldn't work. Idk. I'm a beginner in this kind of stuff.

They work...they're just complicated. Its kind of difficult to keep them in adjustment, but if you can then all the power to ya

Like prancstaman said, you can use the clutch to control the vari-drive. It works pretty well. I also modified my vari-drive a little bit so that I can let out the clutch pedal, stomp it back the other way and the tractor takes off instantly.

AllisKidD21 wrote:

Like prancstaman said, you can use the clutch to control the vari-drive. It works pretty well. I also modified my vari-drive a little bit so that I can let out the clutch pedal, stomp it back the other way and the tractor takes off instantly.

LOL, nice....