Daughter's Race Mower
So... throughout the summer some friends and our families regularly attend the redneck mecca of motorsports, figure 8 racing. The track is a few miles north of town and in addition to the figure 8 races, at the beginning, they have kids lawn mower circle track racing.
After a ton of sideline smack talking, late during the summer of 2010, my buddy donated a 1970's John Deere 210 for my daughter so she could start racing. Definitely not the optimum platform, but since it was free and ran ok, it's what we decided to use.
The bad part about the Deere, is it's not a Lawn Mower per-say. It's a garden tractor. Meaning it's built like a tractor. It weighs a ton! It has 1/4" frame rails and is geared super low. Not to mention it only comes with a 10hp Kohler vertical. Most of the competition is running Murry's or something much lighter with 15+ Hp engines.
We only had a month before the next race, so we rigged up a foot throttle and did a few pulley swaps and got a roll bar and all the safety equipment required per the rule book so she could get racing.
First season was fun and she had a good time, although very nervous at the beginning of the race, by the end of each race she was comfortable and pushing it fairly well around the track. She was consistently in the middle of the pack and despite all the disadvantages she had with the platform, we had an awesome dad/daughter time doing it!
Over this last winter, we really didn't make any changes. We knew she was in the middle of the pack and we were close to exceeding her abilities anyway. The only real modification we decided to make was the move to a heavy duty centrifugal clutch. The manual spring clutch on the old John Deere was definitely made for a full grown man. I ordered the clutch with a 5.5" pulley to replace the 3" pulley on the motor and up the speed a little bit. We also found out we had a massive head gasket leak, so we milled .080 off the head and bolted it up with studs for a huge bump in compression from the stock 6.5:1 We figured that should be plenty of improvement for this year. We were wrong.
We showed up to the first race feeling fairly confident, but turns out everyone else was drastically changing everything and she got smoked to a last place finish. We both were caught a bit off guard and were also a bit upset. The rule book has basically been thrown out completely and they didn't even do a tech inspection this year.
So that being said, we started to look closer at our stage III options. One thing I had ordered prior to the first race, but didn't receive yet was a tiny tach. In the first season I had broke the governor spring and replaced it with a similar tension spring from the hardware store. It wasn't factory, so I played around with it a bit until it sounded about right (yeah right) and we ran it. Well I got the tach the following week after the first race, hooked it up and come to find out we were only running 2800rpms wide open. The stock setup is governed at around 3500. My buddy that pulls with these motors said they're fine to 4200rpms. So after some more work on the governor, this damn ******* came ALIVE!!
So, the second race of the season we went back and forth about running 4th gear and taking a larger turning radius, or dropping to 3rd and taking advantage of the turns and the acceleration we suddenly found the thing had. We ended up running 3rd gear and she pulled a 4th place after almost rolling it in the first turn of the night. She started braking halfway down the straight for the next few laps and got almost a lap behind, but after she got comfortable again, she was catching them pretty quick. Unfortunately it wasn't enough, but still, I was pretty impressed with my little 10yr old girl braking hard into the turn and stomping it halfway out the back!
So being she almost rolled it, we moved onto Stage III. Lowering and widening. We built adapter/spacers for the rearend to go from the Deere 5x4.5 pattern to a 4x110 pattern so we can run atv wheels. Actually, I pulled the carbon fiber Hiper beadlocks off my quad with tires from the 12"/23" stockers and air them down a bit to get a little tire suspension out of them. The new front axle was built and mounted and she was able to attack the turns at quite a bit higher speed.
She raced with that configuration through the 2012 season and was consistently mid-pack. She did great and I couldn't have been prouder of her! She became more aggressive and precise in her actions the whole year. She really came into her own on the track. In my mind though, the chassis was now again the weak link.
Onto Stage IV!!! After conforming to the rules which no one follows and are not enforced in any manner, we've decided to play their game. An opportunity came up to pick up a brand new Kohler CH730 (25hp) motor for dirt cheap so we bit. Tons of changes were made in every single area of the mower to make it not only competitive, but push it well beyond anything else that showed up. Maybe I took it a little too personally, but I wouldn't be surprised to start seeing the rules be enforced again after this season..
Here's a quick down and dirty list of Modifications we made this year:
Kohler 25hp Engine
Carburetor change
electric fuel pump install
valve springs and retainers (7000rpm support)
stainless 1 1/8" primary / 1 1/4 secondary header build
build new engine mounts
clearance frame for new engine
build new idler system for direct drive with arm and spring adjustment
clearance belt locations
weld up all frame holes
pulley swap on transaxle
1 gallon fuel tank
removal of the variable drive system and all bracketry and supports
boring and broaching of centrifugal clutch from 1" bore to 1 1/8"
removal of stock fuel tank under the seat
cutting and re-welding of the rear fenders to drop the seat pan 4"
welding of subframe for new race seat
welding of harness supports
cutting and relocation of steering box to zero angle as opposed to the offset angle to support linkage
move bushing support to support steering linkage outside the frame to reduce drag link angle
shorten drag link 3"
flipping of tie rod to clear new draglink
repaint
re-stencil all decals
swap out beadlocks from the 23/22" setup to MX 20/18" tires
After the second race of the season and being almost a lap ahead two laps into the race, she lost control (due to the very sloppy 1970's mower steering) and hit the wall. the steering box actually broke and she was out of the race.
We then picked up a 14" rack and pinion and integrated it into the mower. No more slop for next race! This thing drive like on rails and she should have no trouble destroying the whole field next race!
Here's a quick test and tune vid with the new setup.
Anyways, on to the pictures!!















when i was younger I had a "mower" (no deck, not even sure what it was) but anyway, it had an emblem that just said Rat on the hood (not sure where the emblem came from either) I worked the engine all I could on the lack of a budget, some porting, bigger carb, took the head to a belt sander, etc. hooked up a wire to override the governor, and while i never swapped pulleys to make it fast (it was worked around the yard) it could do some pretty good wheelies...
me and my brother nearly installed a rotax 440 on a lawn mower once, still kinda wish that we did
now days I just wonder about v4 outboard engines...
That right there is the stuff dreams are made of, and thousands of happy memories - it's good you could get together on a thing like that...
Tell her the fuzzy little old man from Memphis said:
"YOU GO, Girl!"

~Might wanna check into some "HI-LUG" tires, if the budget permits
I think what I put on the ol' BULLFROG ran to $70 each at tractor supply Co.
I warn you they are a dog in heat to stretch over those rims - unless you grease them around the bead with vaseline...
But that trac' right there could climb a tree when the deck was still on, and the blades cutting!!!
*I use it for a puller now
* It might make the ride kind of bumpy...

(Those are 12 volt utility lights on the front. I got sick of the lame lighting)
**Tractor lights usually run on a separate circuit from everything else. But it's still 12V. I just bypassed the originals with wire taps!
That last pic is famous here - the deck was still on it.
~Gotta love a craftsman six speed
People have asked me if it was made up - but it wasn't. I just revved it in 6, and let the brake pedal up. It was not staged or faked up at all

If nothing else, I hope this encourages you - a lot can be done!
Definitely something we both enjoy and she's definitely not your normal 11yr old girl!
We got some helmet cam footage of the race last night. Her pit crew(me) wasn't on the ball and the throttle cable had slipped (after breaking earlier in the day from testing) and she was running 1500 rpms low. Had I caught that, the race would have been a much different story!
"Stupid people are their own PUNISHMENT!"
*snnikkkerrrezzz*
My connection I guess made the video error out. But getting more speed means parting with big bucks...
I'll try again after midnight, when fewer people are trying to go to that site.
We spin that Kohler to 7000 rpms and we've got plenty of expensive parts in it to make sure it does that safely, including dual valve springs and a billet aluminum flywheel.
Ground speed is about 32mph, which is plenty fast for her, but our limitation is in the transaxle which is geared extremely low. We're currently spinning the input shaft the transaxle at 10,000 rpm's which is loads beyond the 2600 it was originally intended to turn. I actually called the engineers at Peerless before attempting it to get their take. They suggested we run 20W50 as opposed to the 90W oil to make sure all the roller bearings got plenty of lube. It leaks a bit out the seals, but it's held up so far.
Next race we'll have her back up in the rpm range and kicking butt and taking names.
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We spin that Kohler to 7000 rpms and we've got plenty of expensive parts in it to make sure it does that safely, including dual valve springs and a billet aluminum flywheel.
Ground speed is about 32mph, which is plenty fast for her, but our limitation is in the transaxle which is geared extremely low. We're currently spinning the input shaft the transaxle at 10,000 rpm's which is loads beyond the 2600 it was originally intended to turn. I actually called the engineers at Peerless before attempting it to get their take. They suggested we run 20W50 as opposed to the 90W oil to make sure all the roller bearings got plenty of lube. It leaks a bit out the seals, but it's held up so far.
Next race we'll have her back up in the rpm range and kicking butt and taking names.
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Midwest Super Cub
These guys actually have several 25hp Kohler Commands up in the 120+ hp range. They have a youtube video of one making 120@12,000 rpm. It's a beast.
The other place I get valvetrain stuff from is Vogel Manufacturing. They also make a bunch of parts for the ignition.
Home | Vogel Manufacturing
Heck I even teared up a bit seeing the photos and the video---just too damned cute in this old guy's opinion!








