PDA

View Full Version : Lawn Mower racing



steveo
21-07-2015, 12:52 PM
Anyone built a lawn mowing racer out of an old ride on? Looks like good fun. Unlike kart racing you can take it off road.

I'm interested in how much more speed you can get out of an existing mower and how?

http://www.lithgowshow.org.au/showmow.html

https://www.youtube.com/watch?v=bWzmdtQ-o-Q

steveo
21-07-2015, 02:11 PM
I don't think I'd be after too much speed, just a cheap method to have a bit of fun with the kids. From reading a pulley swap and removal of cutting deck might do the trick. Maybe lowering it a bit also. What is the best candidate of mower? Obviously I'd look for one where the pulleys where easy enough to change and there was enough room for the oversize. Anything else to look for?

Mow And Go
21-07-2015, 03:11 PM
lol I know a few guys back home that put street bike motors in them. I had an old rover that had an RGV250 motor in it, but the best ive seen was my best mate back in the day put a hayabusa motor into an old greenfield just to say he did. never ran it full throttle for obvious reasons lol

troppo
21-07-2015, 06:46 PM
From my Sprintcar/Speedway and Go-Kart days, all out speed isn't everything. You need to be able to get around corners quicker than anyone else. Higher entry speed = higher exit speed. With go-karts, all the handling is mainly in the front end. While stationary, when you turn the steering wheel more weight is put on either back wheel to the point where the opposite front wheel will come off the ground. This is all achieved through the angles of the king pins on the front axle, so you need to be able to play with those angles. If you don't get that weight transfer, when you try to go around a corner, it will want to go straight ahead (push/understeer) Simply putting the front wheels further out on the axle stubs could achieve the desired weight transfer. (offset rims or putting the original rims on inside out maybe) Don't go overboard with the pully changes to the point where the motor bogs. Low down grunt (torque) is best if you can modify your motor to achieve that. Shave the head at least and get a more efficient carby if possible and run the highest octane fuel that you can lay your hands on. Don't run old hard tyres, the softer the better, but that all depends on surface you are racing on. There's so many little things you can tinker with, but those are the main ones.

troppo
21-07-2015, 07:14 PM
Just thought of another one, cut, grind off, remove any excess weight without sacrificing safety. Any excessively long bolts, cut 'em back, metal mounting tabs that are square, make 'em round, or too thick, make 'em thinner.The more you look the more you will find. Oh, and another one, play with the carby to up the revs and run semi synthetic 2 stroke oil at 100:1 in your fuel.

djkgrounds
21-07-2015, 07:41 PM
A few of my dads old clients in NQ were Mower Racers, They had a couple of old Greenfields and a couple of old Cox rideons, running from memory 12.5hp modified Briggs motors with tuned mufflers. They were bloody quick. Rear axles, wheels, hubs, spindles, and brakes etc. were from go-carts

steveo
21-07-2015, 08:00 PM
Could you speed up mowers with a hydro gearbox or not?

seliment
21-07-2015, 08:09 PM
..... just a cheap method to have a bit of fun with the kids. From reading a pulley swap and removal of cutting deck might do the trick......Anything else to look for?

Be aware ... Motorsport (& boating) and cheap seem to be mutually exclusive in my past (limited) experience.
Maybe look at a new / better (racing) carby and air intake/filter system if the rules allow.
If there is sloppiness in steering -- see if you can remove it as you don't really want a 'wobbly' steering wheel.
After that ... $'s might give you a souped up 'computerized' ignition that has spark advance etc.
I think there are even kits avail that will allow you to convert many of these sorts of motors to fuel injection -- with lots more performance if rules permit.
Sounds like fun. ... But not as much as the raw untamed HP of tractor pulling :) :)

djkgrounds
21-07-2015, 08:14 PM
They usually run a right angle gearbox (RAGB) at a 2:1 ratio

BSD
21-07-2015, 08:49 PM
What about a zero turn thing going for it..

Cranbourne Lawnmowing
30-07-2015, 08:19 PM
Bloke who lives over my back fence races mowers and builds some beasts including putting a V8 in a ride on. Sorry i cant tell you what the machine was, I only heard it didn't see it but it made the windows rattle.