# Fast



## caleb (Oct 16, 2012)

What size pulley should I put on to go fast but not break the transmission any ideas


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## bwgad96 (Mar 18, 2012)

How fast do you want to go, and what transaxle are you using? Does it have any modifications such as being locked?


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## caleb (Oct 16, 2012)

I'm using a six speed trams axle n no it dosnt lock n I was hoping to go at least 20 mph or faster


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## wjjones (May 28, 2010)

caleb said:


> I'm using a six speed trams axle n no it dosnt lock n I was hoping to go at least 20 mph or faster




For that speed you would need the engine pulley to be atleast 1/4th larger than the rearend pulley. I increased my ground speed by about 2.5 mph by adding a 4.25" pulley to my engine, and a 4" pulley to the rearend.


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## caleb (Oct 16, 2012)

Thank u sir


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## wjjones (May 28, 2010)

caleb said:


> Thank u sir



You are welcome let us know how it turns out when you get it done.


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## dangeroustoys56 (Jul 26, 2010)

Dont forget to put some brakes on it - stock ones wont do. Also remember stock tractors arent ment for high speed - other things should be considered like locking the front axle - id also suggest pulling the trans out, cleaning the old gear oil/grease out and adding fresh heavy weight oil/grease in it. 

I had a stock 85 LT12 craftsman I tinkered on - thing would run around 20- 25mph - no brakes - then the trans locked up as i was taking off one time - im probably lucky it didnt happen while at speed. Couldnt stop it either - pretty much had to let it slow down on its own.

Youre limited on how big of a front pulley you can use on a craftsman, due to the clutch setup - i ran a 6" on the motor and the clutch pulley would contact it with a screech.

Just letting y know how it worked with me modding my first tractor. Id also highly suggest a helmit.


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## caleb (Oct 16, 2012)

Thank u for advice I'll take it


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## caleb (Oct 16, 2012)

Now I've decided to change pully n do an engine swap from a 12 hp to a 18 hp v twin any ideas on how I could get the best out of the engine n size of pully n how to measure wht size belt I need


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## dangeroustoys56 (Jul 26, 2010)

I ran a 18HP flathead twin on a murray with the 6" pulley and a 6 speed 'shift on the go' trans that had a 3" trans pulley - thing had all kinds of power, even with the governer still attached. It couldve went over the 30mph i reached with it, i couldnt control it tho - was way to squirelly .

Problem with newer motors is theyre so full of plastic ( for EPA and noise regs) and detuned they can hardly get out of thier own way - only way to get around that is to have a ton of speed parts in it - and isnt cheep.

More power adders would be to simply add a foot throttle and an upgraded carb . 

Problem now is you cant keep the tractor in stock form - steering needs to upgraded, front axle locked, wheels need to be changed and properly affixed ( loosing a wheel at 30mph would be bad) .

From experience ( take it or not) - using a stock tractor for going fast is a bad idea - my murray was the fastest one i ever built , was 90% stock and it scared the crap out of me - it would dart side to side randomly , was hard to control - nearly crashed it more then a few times - i like walking and breathing normally - im sure if i was more reckless id be either paralyzed or worse.

I built a mod MTD breifly ( needed the chassis for another tractor) , with the front axle locked, lower stance ( simply raised front axle up into chassis and put lower profile rear tires on ) and lower seating position - just those simple mods made a huge difference in handling and felt a whole lot safer to drive - actually felt like driving a 'big wheel' when i was a kid - could throw it into corners hard and felt tons more stable, just with a few minor modifications.

Id highly suggest researching on building a racing lawntractor , even if its not used for racing .


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## caleb (Oct 16, 2012)

Thank u for your experience because I'm only 17 and I'm not lookin to go really fast prob bout 30 but I'm using it as a mud rig too soo basically a cheap atv lol n thank u


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## caleb (Oct 16, 2012)

And if u have anymore info tell me n btw I'm nts not a new motor in putting in its a 18 hp v twin tht is 9 yrs old


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## dangeroustoys56 (Jul 26, 2010)

I own a couple OHV motors but i have more flatheads - sort of as a test i used my 1999 6speed 13HP flathead murray stock mower in a power test against my 16.5HP OHV 2003 murray 6 speed stock mower - the flathead had way more power - to me it just seems the stock OHV motors ive used just dont have as much power , stock or in a mod tractor. 

I used an old stock 80's agway down in the swamp behind my folks house for years - had a 10HP briggs , stock tires and stock pulleys - it has a slow 3 speed peerless , so i did a mild pulley swap - 4" motor and 8" trans pulley - it bumped the speed up in 3rd , but mostly used lower gears in the mud because of the terrible stock tires .

Since its for mud, id look for a set of ATV tires for best traction- check flea markets and craigslist - used wheels can be found reletively inexpensive - larger front wheels can be mounted by welding an extension onto the end of the spindle, ive seen some tractors with really large tires up front - they welded a stock steel rim to the larger rim and were able to use stock spindles. If mounting larger wheels, the spindles should be reinforced for the extra weight of the larger wheels.

You might also want to reinforce the front axle/mounting points as well. 

On my agway i planned on making it a trail/mud tractor - eventually i wanted to do a 4x4 mod - using a rear steer noma type setup up front on a transmission , but i found a cheep GT murray to use for the base tractor ( has 1" spindles and 1" rear axles) - when i get around to building it , itll eventually get the 4x4 setup as well. I bot some cheep used ATV wheels for it , so should have plenty of traction.


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## caleb (Oct 16, 2012)

Thank you for ur info sir


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