Jonny's Mad Max super quick build

So, here is my daft quick build. I'm certainly not expecting to win with this! Just thought I'd enter so I can share my build experience and get useful feedback from you lot.



So the purpose of this build is for a sort of racer for my stag weekend, where I'm planning getting a group of my mates in a field with some mowers and race/have fun/do jumps etc before going to the pub for drinks.



So this is the main pile of bits/mower I will be modding. I got the mower of the bay last year for £26. Got it's 7hp Briggs running. I'm swapping the engine for a 12.5 Briggs. Using lots of old school table frame for strengthening the rather flexible chassis.









So, first of all pressure washed everything. Then stripped everything.



Dropped in the 12.5 HP



The 12.5 is a few inches taller than the 7. So I used some table frame steel to frame up a new seat frame. This is also to make the chassis more rigid.



So this is as far AS I got on the first day of building. Pretty it defo isnt! I'm thinking of making this a rather silly build. It has a pretty high centre of gravity so I'm considering putting some anti roll stabiliser wheels on the sides. Or (as the diff seems to have siezed) extending the front and rear track  by10" or so. solid axles. Dunno if I'm honest. Very much make it up as I go along! Watch this space!

Is there some sort of way to take the engine off?

Come on red, you just cut then re-weld. Only takes a few minutes. Kind of a neat little mower though. Pretty simple design from the factory, mostly a flat piece of stamped out tin.

Yup, the grey box section frame unbolts.

jonnya wrote:

Yup, the grey box section frame unbolts.

Oops, I totally didn't see the bolts in the back lol.

Welcome to the Build-Off! Sorry I'm late qualifying you, I've been outta town for a few days. Good luck!

So, not as much progress as I'd have liked this weekend. Did nothing really to the chassis except removing the axle.
I've been on the lathe swapping centres of pulleys for a pulley swap. I seem to have lots of big pulleys and it's easier to cut the centre of a large one to let into a smaller one rather than having to take pulleys to an engineer and paying for a keyway to be cut. Pulleys seem quite expensive in the UK for what there are.





Here's a close up of the small pulley with new centre. This is now welded up. Will take a pic next time.





Next thing was trying to get the wheel off the axle. Hours of fun this was! I had all my 'weapons of mass destruction' out on this! Absolutely stuck fast! Even destroying the rim took lots more time than I'd have liked.

So, not much big change on this project. Ihad to wind my neck in a bit as I spent several hours thinking of ways to re-engineer a single speed MTD transaxle onto the back of it. If this wasn't a quick build project I'd have continued. I think the gearing would have been a bit daft though. This would have mainly used up too much time.

So, some progress today/yesterday. I have welded some 2 x 1 box to the bottom of the chassis to tie the front and back together a little more convincingly. There was defo a good bit of flex in the chassis! Hopefully this' and the seat frame will take the whip out of the chassis.






Here's one of my cats Rory. He's more often than not in the shed whilst I'm working. Somehow he's not the slightest bit bothered when the grinder, welder etc are going!



So here is my brake disc carrier. I machined it on my lathe from a piece of 2 inch diameter x 1 inch bright steel bar. This is then welded on to the axle. A bit permanent seemingly but should I need to remove it, which is unlikely, I can machine away the weld on the lathe.



So here is the disc in place, but not bolted. The disc is off of a mini moto 5 inch diameter. Dunno if anyone's tried this before - only having one side of the axle braked? Feedback appreciated!

So a little more progress today. I only had a couple of hours on it today, spent the morning looking for a wedding suit, yay. I must be the only person in the UK wanting a chocolate brown suit! Can't find one anywhere! I digress. So I made a bracket for holding the brake caliper and a centre axle support. I've decided to use the original brake/clutch pedal if I can, and connect a cable to operate the new caliper. This will then cut power to the axle as otherwise half the axle could be under power whilst half is braking. I'll hook up the dinky brake on the gearbox too. Every little helps I guess.



As this mower is (supposed to be!) a quick build for a bit of fun for an afternoon with my mates, I'm trying to keep costs down, hence my re-use of the bronze bearings/bushes. There's a little  play, but they'll do. I want to put some triangulation bars from near the axle to the centre of the chassis, tomorrows job!



I have pretty much a whole day on this tomorrow, my aim is to have it driving/finished, optimistic I know! Watch this space.

you should really put the brake on the diff but too late i guess

I put the disc on the diff on my rat rod tractor. It works well when both tyres have contact with the ground, but has no effect at all when one of the tyres leaves the ground as the wheels then are free to spin in opposite directions. Ideally I need a disc on both sides of the diff, but there isn't space. Or one on the diff and one on the axle. My plan is that by having a combined clutch/brake pedal, there will be no power going to the axle whenever the brake/clutch is applied.

Everything looks rigid and should hold up well! Im sure youll work out kinks to make it perform in any conditions/any time you want. Always wanted to build a mega offroad RER just like that classic murray, just because nobody has. Maybe next project.

The brake isn't as bad as a pinion brake, but you will be much happier with locking your diff, or solid axle.

So my plan of getting this finished over the half term term holiday didn't quite work out! Nowt wrong with optimism I guess! I've got as far as reassembling it. I think I'm going to weld the diff up, enough of you have convinced me its a good idea.
I havent any new pictures and I'm not venturing outside as it's 1st June and belting down with rain outside, British summer! I couldn't finish largely due to not having a suitable sized belt for it. I have a collection of 20-30 v belts, all too long or too short! I played around for too long with trying to make it work another way with longer/shorter belts, then decided to buy a belt. A false economy really when the belt was only a few pounds. I've ordered the one I think is the correct size and the next size up/down to be sure! I defo want to have this done and running by the end of the weekend though.

Hey jonnya, is that a homemade woodstove in that one picture? Tractor is progressing some anyway, rear axle is pretty neat looking.

Yup that's what keeps me warm in the winter. Made out of an old gas bottle. Kids, don't go grinding into a gas bottle! Even an 'empty one'. DO YOUR RESEARCH FIRST!

So, it's 0844 local time, my other half's out with friends pretty much all weekend which gives me an extra long 'shed ticket'! I think I have everything I need to complete project number 2.
Incidentally, my mower stag weekend is still very much going ahead, a slight change is the event. My friend's dad wasn't too keen on Blokes + Beer + motorised vehicles in his field, so we are going to do the same, but will be more of a time trial. I am building some obstacles: a couple of ramps, a large sheet of plastic + liquid soap for doughnuts, and a see-saw (I think you guys call them teeter-totters?) to drive over. Should still be heaps of fun.

Neat. You'll look like these guys only on lawn tractors.

A bit like that but not that high!

Update, pics and video of this project coming soon! Soz I aint been on here for ages, been getting married etc!

This build is pretty much complete. Watch this space.

Looking forward to seeing this done Jonny!

Hi, although I know this isn't really a contender, I'd still like to enter this as its the only one of my 3 projects I actually completed! I don't have any good photos, I can get some at the weekend if needed. It's dark when I get home from work at the mo. I have got a pic of it finished from the summer, July sometime. My Nephew having driven it up a bank in a big puddle.



and here is a video of him driving along the same track, listen for the belt slipping when wet! Or just wait till it stops in a puddle..

Check out my fuel tank at the end of the video. It's and old fire extinguisher! I'll be happy if I win 'Best fuel tank'!

That was so the wrong video! Soz people.

This is the one to watch. Check out the fuel tank.