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:
racing riding mower questions
- Thread starter 2stroked
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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.
Dangeroustoys56
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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.
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.
motorrefurb
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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 
Belt ratios are important too, I would go on YouTube and see videos of others lawnmowers and find the ratios they use :biggrin:
Belt ratios are important too, I would go on YouTube and see videos of others lawnmowers and find the ratios they use :biggrin:
reynoldston
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Dangeroustoys56
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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.
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.
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.:biggrin:
:biggrin: