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racing riding mower questions

#1

2

2stroked

I've always wanted to make a racing riding mower, now I have that opportunity I have some questions about making it. There is a older rally riding mower for sale that is 250obo. It's in good shape, new battery guy says that he has maintained it. I'm wondering if this would be a good mower to use? Also, I was thinking about a 3 1/2 inch pulley. I would want it to go about 30mph, any faster would be too much for me. I forgot to mention that the engine is a briggs and stratton 12hp i/c engine. The thing that i'm mostly concerned about it stopping power. Do I need to modify the brakes in anyway? If so, how? Thanks for any imput.


#2

reynoldston

reynoldston

I don't know your skills or age? A lawn mower is designed for less then 5MPH and being stock and high speed you could be asking for problems. Maybe add some caster in the front end and brakes from a ATV or motorcycle? I guess it would be how fast, where you are going to run it and why?


#3

Craftsman13

Craftsman13

A fast lawn mower is pretty cool but I would suggest buying an atv or dirt bike because they are a lot safer at high speeds.


#4

K

KennyV

You "could" race anything...
But if you are referring to actual sanctioned racing... you will find there are several 'requirements' that have been established over the years to keep things fairly safe... SEE : The United States Lawn Mower Racing Association

But to answer your question... Yes you will Have to put actual brakes on it and various other changes to allow you some 'control'
Any time you alter anything to do something it was NOT designed to do... You will have to make the needed design changes... :smile:KennyV


#5

Dangeroustoys56

Dangeroustoys56

Ive had a few modifed tractors over the years- ive done alot of research on building them as well- mine were for personal use.

Ive learned a few things - stock and speed dont mix. My first one had NO brakes and i trashed the transmission ( luckily as i started out, not going 40 mph or so..) - built a second one, stock brakes were worthless, was insanely fast ( i never had it wide open) was just too unstable ( took that apart, was scared to drive it) - last one i put lower profile tires on it, locked the front axle ( best for stability), lowered the seat to the chassis - it reminded me of a 'big wheel' trike driving it , but it handled excellent - like a slot car- i could throw it in corners and not be afraid of flipping over, but the speed wasnt there- i took that apart to redo it . Its been the best machine so far.

I suggest you definitely do these mods:
-brakes ( small motorcycle or go kart brakes will work- hydraulic are the best)
-raise and solid bolt /weld the front axle ( NO swivel)
-lower profile tires( lower center of gravity/more stability)
-drain the transaxle of old oil ( if applicable) and put heavy duty gear oil in it ( thick stuff) - the trans will whine horribly ( not designed for speed) - i used lucas oil in my second one's trans
-solid bolt the seat to the chassis
- some sort of bering type wheels up front
- bolt or lock the wheels on ( imagine 20mph and a wheel flies off.....)

And wear saftey gear ( helmit definitely) - i always did


#6

2

2stroked

I guess I should clarify some. I don't really want to race this thing, I just want to have something that I can mess around on. Here is the ad

I have an older 42" Sears Rally Riding Mower for sale. It is in excellent running condition and mows excellent as well, overall this mower is great. It has a 12 HP Briggs & Stratton I/C engine. It is a 7 speed transmission with 3 high, 3 low and reverse gears! I have taken very good care of this mower when it comes to routine maintenance. New battery 2 months ago. I would like to sell this mower this week. I am going to be moving soon and wont be needing it where I'm moving too. I also have 2 ramps to go with it. They are 2X6 with steel ends bolted on for ease of getting into a pickup truck. $250.00 or best offer. Please serious inquires only. Contact me through Craigslist and leave me your phone number so I can contact you! See pictures below....



it's NOT ok to contact this poster with services or other commercial interests


the problem is that it is aways from my house, so if this won't work then I guess it won't be a huge deal

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#7

K

KennyV

It is possable to get hurt on Anything... add any kind of speed to it and it becomes inevitable that you will get hurt eventually... How well you prepare for that will determine how bad you hurt yourself ... or someone else...
A stock lawn mower at 15 mph is an accident about to happen.
You should consider using that mower ... for mowing, at about 4 mph... :smile:KennyV


#8

W

wpc1995

ah kenny thats no fun lol :) go to my youtube channel (wildpanthercutlery) and look at the red murray, it had a stock pully on front and a 5 on the transaxle and it ran good, nice and stable, i put a 5 on the front later and it ran bout 25 but in first gear it was pulling our big smoker around the yard real easy,loaded with wood, ( it a 250 gallon propane tank )


#9

K

KennyV

While I was posting the last comment, I was going to add...
If you do speed it up... have video of every time you run it... as you will never know when the "exciting" clip will come along.... :smile:KennyV


#10

Dangeroustoys56

Dangeroustoys56

Itll work for modding - i wouldnt pay that much tho to just take it apart and mess with it - id look for a cheeper tractor with like a bad deck.

I dont race mine either- theyre just experements to see how i can get a governed motor to push a tractor.
Ive looked through lawntractor racing sites for ideas to set up future machines . If you remove the governer, the motor needs to be properly prepped to handle the higher RPM's - stock flywheels will explode if ran over 3600 RPM's repedily - properly prepping a motor isnt cheep either.

Racing tractors require a certain set of rules, i dont have time to build one to guidelines and race it every weekend- its also too competitive and expensive . I , like you, just want to tinker and run em around once inna while.

The mods i suggested are more for personal saftey then anything else - sitting way up high makes it unstable at faster speeds , along with the unlocked front axle- it wobbles and sways terrible - lower seating and locked front axle help tons on stability - lower profile tire lowers it further.

Most these mods are easy to do, and dont cost very much, but make it handle tons better.

Brake setups on a stock trans wouldnt be easy - youd need one on each side . In a panic stop youll definitely need them.

Ive thought of going to an auto junkyard n looking for a set of discs/calipers off a small car, then getting a rear hydraulic master cylender from a motorcycle .


#11

B

benski

2stroked said:
I guess I should clarify some. I don't really want to race this thing, I just want to have something that I can mess around on. Here is the ad

I have an older 42" Sears Rally Riding Mower for sale. It is in excellent running condition and mows excellent as well, overall this mower is great. It has a 12 HP Briggs & Stratton I/C engine. It is a 7 speed transmission with 3 high, 3 low and reverse gears! I have taken very good care of this mower when it comes to routine maintenance. New battery 2 months ago. I would like to sell this mower this week. I am going to be moving soon and wont be needing it where I'm moving too. I also have 2 ramps to go with it. They are 2X6 with steel ends bolted on for ease of getting into a pickup truck. $250.00 or best offer. Please serious inquires only. Contact me through Craigslist and leave me your phone number so I can contact you! See pictures below....



it's NOT ok to contact this poster with services or other commercial interests


the problem is that it is aways from my house, so if this won't work then I guess it won't be a huge deal
Click to expand...
heymow.com is one of the premiere racing lawnmower sites that I've found so far. The lessons and advice that are contained in it are from people that have "played" with fast mowers for quite a while, and have come through years of sometimes painful experience. PLEASE don't wreck yourself on a mower that hasn't been modified safely. I wouldn't expect my street car to handle well at double or triple its stock top speed without courting disaster; a stock lawnmower presents similar challenges.:wink:


#12

O

Outdooz

I made a racing mower last summer with a murray 14.5hp. All i did was put a 8 inch on the engine and a 3 inch on the transaxle. It almost goes 20. So if you want 30 you need to dump the transaxle and go with just an axle.


#13

Dangeroustoys56

Dangeroustoys56

Thats what my second mod tractor was - a 94 murray with a 6 speed shift on the go - it had a 14.5HP OHV briggs that could barely get out of its own way. Im not saying OHV motors are bad, as they can be upgraded with performance parts to be better, but at a cost tho - you can dump thousands into a hot rod motor easily- im trying to do mods with a stock, governed motor - a bigger motor is a better alternative because it doesnt have to work as hard.

I wasnt impressed with its performance, so i found a MTD with a 18.5HP twin opposed, swapped that on the murray, used a hand throttle on the steering wheel ( this gives it crisper throttle response and better control), added larger wheels, bering front hubs , added super thick gear oil to the trans, 6" motor and 3" trans pulley - in 3rd gear that thing went well over 35mph - i never used any higher gears because it was way too unstable to go faster ( would ocasionally dart side to side) - i had a couple near crashes so i took it apart - it scared me to drive it like that, i shouldnt of probably even tried to after its inital run in that form either.

The prospect of winding up in a hospital with serious injuries or paralysis convinced me to build a safer tractor , one that can handle well and actually stop when i hit the brakes .

One cobbled together might be fun, but have something break while going over 20mph - thats a free ticket to the ER - IF youre lucky. Its better to take the time, build it right and can still enjoy it.


#14

motorrefurb

motorrefurb

I would lower the body and get smaller wheels first, also a billet flywheel and piston so the engine can handle all the power and strain. Also for more performance, you can bore out the cylinder or if thats too costly you can always get a bigger carb or drill out (carefully) the intake ports on the carb and engine block. Another thing you can do is completely disassemble the carb and clean it with some carb cleaner and overall clean the mower :cool: Belt ratios are important too, I would go on YouTube and see videos of others lawnmowers and find the ratios they use :biggrin:


#15

reynoldston

reynoldston

Dangeroustoys56 said:
The mods i suggested are more for personal saftey then anything else - sitting way up high makes it unstable at faster speeds , along with the unlocked front axle- it wobbles and sways terrible - lower seating and locked front axle help tons on stability - lower profile tire lowers it further.

What do you mean by locked or unlocked front axles?
Click to expand...


#16

B

benski

reynoldston said:
Dangeroustoys56 said:
The mods i suggested are more for personal saftey then anything else - sitting way up high makes it unstable at faster speeds , along with the unlocked front axle- it wobbles and sways terrible - lower seating and locked front axle help tons on stability - lower profile tire lowers it further.

What do you mean by locked or unlocked front axles?
Click to expand...

Normally a riding lawnmower has a large pivot bolt that holds the front axle on and allows the axle to articulate. On racing mowers this feature gets eliminated for stability.
Click to expand...


#17

Dangeroustoys56

Dangeroustoys56

What Benski said - normal tractors need the swivel front end for obstacles, ect - on a fast tractor thats a bad thing - you dont want ANY flex in the front axle.

Ive raised ( or lowered the front) axle to the top of the chassis and bolted it solid - thats the cheep way , as long as its bolted on good and tight - the better way is to weld it right solid to the chassis.

Motorrefurb: Unless the governer is removed it really isnt necessary to mod the motor, if the flywheel is questionable, then of course get another one. The governer will keep the motor under 3600 RPM's - when over that then a billet flywheel would be absoultely needed , along with many expensive motor upgrades. A guy i used to work with had a pulling tractor - he said he had over $4500 into the motor alone - that twin of mine made my murray move pretty darn quick , and that was bone stock and governed - wasnt even close to engaging the governer .

A better alternative is to get a larger motor if more power is needed, basic upgrades could be anything from a foot/hand throttle for crisper response and a different carb all together - like a motorcycle or snowmobile carb.


#18

B

benski

Don't forget an ignition kill lanyard in your bag of tricks. CHEAP and handy, too. It'll stop any rotating lawnmower parts from grinding on you while you wait for the pit crew to remove the machine from on top of you.:eek::biggrin:


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