Needing high speed gears

[Notsoezgo]

I have a 2007 ez go st custom, that I have outfitted with a Duromax 440 clone using Vegas Carts mounts. I'm also using their pedal start mount and pulley, exhaust header and their 3 circuit carb. I am pleased with the installation so far, except for the gearing. It takes what seems like 1 second if I floor the throttle to reach my maximum speed of 14 to 15 mph gps @ 4000 rpm. I then need to continuously feather the throttle trying not to explode my new motor.

I might add I have the drive belt tight with about 1" deflection, in neutral the belt rides to the top of the clutch and the driven unit opens fully. My cvt is the comet 780. My tires are 22" in diameter.

I wonder if someone would detail the process of installing high speed gears, including tools necessary in the installation.

Chris

[slonomo]

Sounds like you're right up against the governor. If that engine is stock, don't rev it any higher than you are at 4000 rpm.

Those St350's are geared lower than standard carts if I'm not mistaken. You'd have to spin the tire one revolution and count how many times the secondary clutch rotates to figure out your ratio for sure.

If you've ever worked on a differential it shouldn't be too difficult. If not, I'd recommend reading up on it, watching some videos etc. It's not really that complicated, but if you've never seen the insides of a transfer case, cvt trans, or differential, it could give you quite a shock. Lots of gears and bearings. It looks worse than it is. If you are the "engineer type" it'll all make sense. If you skipped mechanical engineering class.....get ready for some studying.

I am not aware of a "step by step" tutorial. There are plenty of guys here that have done the swap, probably could do a search and see what you find. It might take some digging.

Take a look on YouTube too. You'd be surprised what you find on there.

Here's a thread I found that shows a photo
https://www.buggiesgonewild.com/showthread.php?t=154299

[slonomo]

Here's the ME29 Transaxle manual

[Notsoezgo]

Originally Posted by slonomo

Sounds like you're right up against the governor. If that engine is stock, don't rev it any higher than you are at 4000 rpm.

Those St350's are geared lower than standard carts if I'm not mistaken. You'd have to spin the tire one revolution and count how many times the secondary clutch rotates to figure out your ratio for sure.

If you've ever worked on a differential it shouldn't be too difficult. If not, I'd recommend reading up on it, watching some videos etc. It's not really that complicated, but if you've never seen the insides of a transfer case, cvt trans, or differential, it could give you quite a shock. Lots of gears and bearings. It looks worse than it is. If you are the "engineer type" it'll all make sense. If you skipped mechanical engineering class.....get ready for some studying.

I am not aware of a "step by step" tutorial. There are plenty of guys here that have done the swap, probably could do a search and see what you find. It might take some digging.

Take a look on YouTube too. You'd be surprised what you find on there.

Here's a thread I found that shows a photo
https://www.buggiesgonewild.com/showthread.php?t=154299

Ok I'm not sure if I did this correctly, with one wheel down the other up I rotated the tire 1 turn and got 4 1/2 turns on the driven clutch.
I sure do appreciate your insight and advice Slonomo.

Chris

[Notsoezgo]

Originally Posted by slonomo

Here's the ME29 Transaxle manual

Thanks that will be very helpful.

Chris

[Notsoezgo]

How do I decide which set of gears to get 8 to 1 or 6 to 1?

[slonomo]

If 1 axle revolution = 4.5 input shaft revolutions, that would be 4.5:1 ratio. That doesn't sound right. Typically stock carts have a 12:1 ratio, and I would expect a 14:1 out of a low geared utility machine.

High speed gears are usually 8:1, I'd stick with that unless you never want to climb hills with weight on the cart, especially if you run larger tires. 22" should be a good fit with 8:1 gearing with a clone engine.

One thing, don't expect to get huge speeds out of a 4000 rpm machine. At that rpm I'd be happy with 22-25 mph.

Also, your "ACTUAL" tire measurement is critical in estimating speed. Take a tape measure and get a real measurement of your rear tires as you run them. Keep in mind that tire pressure does make a big difference in overall diameter. Make sure the tires are aired at the proper pressure you like before you measure.

You can plug your data into this calculator for an estimate. I find the calculator to be accurate most of the time, but the data from cart to cart is different in my experience.

https://www.buggiesgonewild.com/speed-calculator.php

At 22", 4000 rpm, and 14:1 trans ratio, your theoretical speed would be 18.7 mph. While it's close, it doesn't match your gps speed. That's what I've found, this calculator never matches any of the carts I've ever worked on. It's close, but not exact.

[jjastram]

In my search for gears, for my 2001.5 EZGO, I was told by 2 venders that I needed to disassemble it and measure the bearing size before I order. There were 2 different sizes used. I would think that with the serial number of the gear box you could tell what size is needed.
I also have a question about gear choice. I replaced the stock motor with a Vegas Carts 460. I am not sure if I should go for 8:1 or 6:1. I don't like running it at 5,000 rpm to maintain speed and would like to keep the motor at a lower rpm.

[slonomo]

As I said in a previous post, 8:1 for most big block carts with 2 passengers and no large hills. Once you add weight, tire size, and hills, the high speed gears will impede the carts ability to perform. It's a trade off. If all you are doing is road driving, high speed gears will work fine.

[Notsoezgo]

It does sound like 8:1 is a good choice. My main purpose is to keep rpm's down. This cart is a campground cart, with speeds limited to 20 mph or less. My next step will be finding a supplier for the gears bearing and seals. Thank you for your advice.