My MTD slammed Rat(ish)Rod (New UK member)

Hi people, so pleased I have found this website, been looking for a lawn tractor modding forum for ages! I wondered how many others mower-modders were out there! I'm in Norfolk England and have been building this for the past year or so.

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It's been built on an absolute shoestring. This most expensive part I bought was the battery which was £37, more than the mower cost!

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It's basically built out of two mowers, the MTD and an old Murray 8/30. I ditched the MTD's variable cone/belt transmission/axle in favour of the Murray's separate peerless gearbox and chain drive axle. This allowed me to go as low as I have. It aint possible to go any lower with the set up I am using! I even had to raise the front bodywork as it scraped all the time! Did look very cool though!

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The rear track is approx 4-5 inches narrower so I could fit the wheels right up into the wheel arches. A cutom front axle was made with a good bit of negative camber added (for looks really, I didn't get the calculator out for this!) The seat height is about 10-11 inches lower overall than a standard model! The exhaust (muffler you lot call them?) came out of a skip at work and spent most of it's life on an 1980's Honda motorbike!

It has a diff mounted 10 inch dics and a cable operated caliper from a mini moto. It works, but could be better! I used the old 8hp B & S out of the Murray as the MTD's 12.5hp was earmarked for my buggy project. This may well be swapped over though. Not sure yet?



I don't have photos from the build unfortunately, but I will take some close ups of the oily bits when I get a chance.

I hope you all like my lowered Mower.

sexy build man, love the look of this, you pulled it off wonderfully, just wondering, whats your top speed on this bad boy?

If I'm honest I don't know, never GPSed it. I would estimate I've had it up to 25mph so far. It was pretty hairy if I'm honest, the steering was a little vague at speed! I'm also about 250lbs, so would go much better with a pilot of 'racing weight'! I will take my Tom Tom with me and a crash helmet next time and see what it'll do.

Wow this is amazing! Probably one of the best looking slammed mowers out there. keeping all the body pannels is great. Glad to hear you got a custom axle up front, way better then the stock stuff. Totally killed the look, awesome

ive got you beat by 60 lbs, and i know the whole sketchy steering thing, had a murray run 40 at stock higth and stock steering, was pretty knarly

Awesome looking machine... how does it sound with that exhaust?

not to be buzz kilington or anything, but if you look closely at that first pic, that exhaust is actually a muffler, not a 'trumpet'

willis923 wrote:

not to be buzz kilington or anything, but if you look closely at that first pic, that exhaust is actually a muffler, not a 'trumpet'

I don't see where anyone called it a trumpet.

Here is a quote of what the OP said about it:

jonnya wrote:

The exhaust (muffler you lot call them?) came out of a skip at work and spent most of it's life on an 1980's Honda motorbike!

his post has been edited though so he probably changed it

Damn i like!

People, I think something has been lost in translation here! In the UK mufflers are referred to as silencers although often, where I live, people will call the silencer/muffler 'the exhaust' If I'm honest I don't know what a 'trumpet' is. It came off a Honda super dream which the Janitor at the school I work at is restoring.
What is a trumpet? (other than the popular brass instrument!)

richie thomas wrote:

his post has been edited though so he probably changed it

It was edited more than two days before.

For the record, I edited out my idea for next year build off as my idea is pretty original and wonderously daft! I don't want anyone pinching my stupid ideas for themselves! I am still none the wiser as to what a tumpet is and have certainly never claimed to have put one on my tractor! Anyway, here is some close ups of my mower. No trumpets.



This shows the engine, exhaust manifold/system (header), which was made out of an old chrome chair frame. The steering set up can be seen, more pics to follow...



Here can be seen the steering uprights which are forward facing. This was the only way I could get clearance for the tie rods and go as low as I have. I'm aware there is room for improvement, this is my first build and was an excellent learning experience. The front axle was originally on a buggy I built, I used bits from an old Westwood front axle I bought off of Ebay.
I had to lower the front end twice as the first time it wasn't low enough and sat too high, a further 2 or so inches were removed. The front steering upright have had extra steel plate welded on, this sits inside the rim with very little clearance. The only way I could achieve any sort of Ackermans angle.



This picture shows the foot throttle. This was originally the height adjustment lever from an old Murray 8/30. Pretty crude spring mech. but it works. I used a bicycle brake cable with an extra return spring on the carb. You can also see the extent of bodywork removal needed to get any decent lock on the front wheels. I don't know if anyone has a picture of an unmolested Lawnflite they could post? I didn't take a before and after unfortunately.



Another angle also showing the silencer/muffler. Definately not a trumpet.

I pulled the mower into the shed and lifted the front for some undercarraige shots. Here is the rear axle/disc brake. The brake is from a 110cc pit bike and the cable operated caliper is from the rear of a mini moto. I also have a horrendous oil leak from the gearbox. I foolishly filled it with oil thinking it would be a good idea. I have learnt that peerless gearboxes arent like those on a car and arent oil filled! This brake set up works best when sprayed with brake cleaner first! It still isn't the most effective brakes as I'm asking a lot of such a small brake caliper. It was all cheap however and does work reasonably. You can also see part of the extra subframe which was made to carry the axle. Ths was made up of inch square box, recycled school table frame! I'm a High schoolTechnology teacher and there are probably 3-4 broken tables thrown in the bins each week. I can't see all this steel go to waste.



Here's my clutch mech. Scratch built, rather crude, but works really well. It has a rod linkage throughout as I couldn't seem to get a cable to work. I tried to use an old car handbrake cable running inside a speedo cable outer (bit like a hardcore bike brake cable!) there was too much stretch (I think) Annoyingly I just couldn't get it working. I wanted to use some kart pedals but they weren't man eough for the hefty cable and ended up using the original MTD pedal. It's a combined clutch/brake. I'm using a 2 1/2 inch pulley on the gearbox and I think it's about 5 inch on the engine. I had to buy a new belt.



A full length shot showing the full exhaust. The pillow block bearings can just about be seen. The rear track was narrowed by about 5 inches to allow for the wheels to sit in the mudguards.



Here's my gear lever & linkage to the peerless gearbox. The battery was the single most expensive part at £37! The mower was £30 off of ebay. The linkage (and nearly all the project) was made up off bits and pieces from my mini scrap heap.

Another shot of the front upright. You can see the plate welded on to achieve Ackerman angle. The pushrod from the steering wheel/rack has about 1/2 inch clearance under the exhaust pipe. More recycled school table leg can be seen!



This is my fuel tank which was made from an empty mig welder disposable gas bottle and some old heating pipe. Please don't laugh at my welds. I double then triple welded the join as I wanted to ensure no fuel leaks. I have (and I bet you do too) heaps of these gas bottles which they wont take at my local tip as they are pressurised. They tell me to put them into landfill. I have found several uses for these. Bender's eyes on my barbeque grill!



Guys, please be very very careful if you sre going to start cutting any pressurised gas bottles. Do your research and don't just stove into it with you grinder! If in doubt, don't do it!



This is the 'saddle'. The 'choke' button is the start button. The 'throttle' is the choke and yes that is a spring loaded gate bolt I have used as a reverse gear lock out. I needed something pretty quick as I was taking the mower round to my mates house as he has a huge garden. I didn't want any of my mates wrecking my gearbox by slipping it into reverse whilst going forwards. Obviously! I popped a spring in the end and welded a tiny plate to hold the spring. Works a treat! The grey steel started life as part of a filing cabinet I rescued from the school bins! Why pay for steel when you can get it for nothing!



Here is a side view. If you look at the original decals on the side, this looks like it should be a 5 hp mower. That is the '.5' off of the original 12.5 decal. I had to move the rear body section forward about 3-4 inches so the rear wheel didn't foul the bodywork. The original gearshift gate can be seen.

This picture shows how little clearance there is between the top of the wheelarch and the tyre. It's about 3/8 inch, not much anyway! I really couldn't have gone much lower! I decided at an early stage to leave this as a 'natural rat look' I left all the bumps, scrapes and rust as it was. I really like 'actual' rat look. I'm not a huge fan of 'artificial' rat look. I know myself too well to start going for any shiney paint jobs, I'm way too clumsy and would scratch it in no time. I would like to do a metal flake ride on mower one day though!



This is the sprocket for the drive, the axle is from a Murray 8/30 and has a diff. The sprocket was originally going to be inside the chassis, but I couldn't get the axle narrow enough, so it had to be place outside the chassis. More of the axle carrier frame can be seen. If I could change anthing about this build, I probably try to make it lighter. I haven't weighed it, but it's well heavy! It is defo over engineered in places.



Rear view, not much to see here. I left the single reflector in place as this is how the mower was when I got it and it fitte with the ratty look I was going for.

Overall I am really pleased with how it turned out. I learnt heaps on this, my first build and really enjoyed it. There are a few things I want to improve. I may swap back to the 12.5hp engine, at least whilst the 8hp is rebuilt. The 8hp is a 1988 unit and quite tired. There are a few bits of tidying such as the steering uprights. If you have any questions please ask. Please don't correct any UK/US English spellings, you just spell some things differently!

I am looking forward to entering next years build off. I have an excellent idea. Not sharing!

that trumpet thing is a NASCAR thing, and I find this a really sweet looking rig, by any chance have you chatted with TD? he's from norway I believe?

If I remove all the baffles and glassfibre packing from my silencer I'd pretty much have a trumpet then? I do like the idea of an unsilenced/muffled engine, however I dare say my neighbours wouldn't!

I've not spoken with TD, I've only been on this forum for a few days so hopefully I will get round to it one day. Is he the fella building the speed mower which is being built to race car standard?

jonnya wrote:

I don't know if anyone has a picture of an unmolested Lawnflite they could post?

Hi Jonny I think this is what yours started out like if you`d like it for reference:

Nicely done with this thing. I should spend more time looking around on here, I'm missing all the cool pics. Front axle is pretty neat welded up like that.

Thanks for the big ups!

Look what I was given a few weeks ago by a bloke from work. I'm a design and technology teacher and have photo of my slammed mower on the workshop wall for the students to see my handiwork. One of the teaching assistants saw my photo and said he had a similar standard mower sitting in his garden doing nothing which I could have. I swapped it for £9 worth of biscuits (cookies)! A good swap methinks! He was pleased with his biscuits, everyone's happy. It isn't exactly the same model but very close and demonstrates how much I have taken out of the ride height. Not sure what I'm going to do with it yet? I'm thinking a monster mower as I have 3 ATC (Off of a Honda big red I think?) wheel/tyres without a home. Just need a fourth though. What ever happens to it won't be happening this year yet as I get married in the summer so have heaps of planning and other stuff which will take up my time.

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Man i cant get over how cool that looks. You slammed it like 6 in. How fast does it go?

So I've been in the shed doing some bits to the rat rod mower. I've done an engine swap. It now has a 12 hp instead of the 8hp. I've modded the exhaust.
The 8hp engine never seemed to run too well, could do with a rebuild. It got very hot whilst running, often overheating and refusing to start untill cooled down. I think there were several issues:
1. I think I'd geared the engine too high for the size of engine/me! This caused extra strain on the engine causing it to run hotter.
2. The exhaust header/pipe going into the muffler/silencer had no heat shield and was causing the engine compartment temperature to get very hot, therefore the engine only having hot air to suck in to cool the engine, causing it to run hotter.
3. The silencer/muffler was off of a 125cc bike and didn't flow enough exhaust gas, causing it to hotter.

The mower always ran better when the hood was removed and driven without it. Tis would obviously have an effect too.

So the bits I've done so far are:

1. Opened up the silencer/muffler and removed all the baffles to increase gas flow
2. Used the standard 12hp exhaust/muffler assembly, this still feeds into the bike muffler.
3. Used the exhaust shrouding/heat shield which should help remove heat from the engine compartment

It's not quite running yet as I purchased a new belt which was the wrong size and I want to do a little work on the steering gear as it's a little wobbly at present. Fingers crossed the new engine will resolve my problems!

Any feedback/opinion on my mods/reasons for are most welcome. Every day is a school day!

And I'll get some pics on here soon too. Not much to see to be fair though!