LowStandards builds a Mini Bike - RRG24 Toilet Transport

[LowStandards]

I figured I'd best start a new thread for this

I've shelved the Mini Mini Scamp for the time being to concentrate on the actual Scamp as what I have planned will take a fair bit of fabrication

But I still need toilet transport

I really enjoyed knocking about on the Tomos, 2 wheels really smoothed out the rough ground, so I figured a motorbike it should be.


But you know, motorbikes are boring, mopeds are obviously much cooler, but still, you can just buy them, also I really wanna build something.


Which brings me to one of these, a Mini Bike.  As popular in America as shooting up a primary school, but weirdly not over here






I just so happen to have a 75cc Suffolk Punch engine as you do.  It's got a nice vintage look to it, probably because it's pretty vintage




It makes exactly fuckall power, but it pop pop pops along whilst doing so, so it's ideal


Mini bikes appear to mostly use 10inch barrow wheels, so a good place to start is to buy some of them.

But hold on, driving up the road the other day I spy this dumped along with some other bits of steel on someones driveway.  I of course stole it





What I have there is a Wolf Garten Scooter

What that means in reality is I have 4 10inch barrow wheels, 2 of them are attached to an axle with a differential, the other 2 handily have roller bearings

I also have a working 190cc engine and a Peerless 3 speed/R gearbox, but they'll get sold for cash money


The choice now is, build a 2 wheel Mini Bike as above, or use the axle to build a Sidecar Mini Bike like this





I kinda like the fact i'd be able to stop and leave it somewhere without it falling over if it was 3 wheeled, plus it makes it eligable for the Sunday track run, so lets make it 3 wheeled.


The 'Scooter' died for this, but i'm not bothered, it was an odd thing and it was free anyways















Let me have your thoughts, persue with the sidecar (it wont have a cooler on it) or make it 2 wheeled?

[Jonny69]

I’ll just leave these here just in case.

[jimi]

Three wheeler gets my vote less mainstream than 2 wheels 👍

[93fxdl]

Hide the engine inside the cooler, have a hamster wheel where the engine would normally be, for extra mayhem, connect the wheel to the axle, so it turns as the trke moves, with a fake hamster inside it
Ttfn Glenn

[LowStandards]

Calm down lads 😂


It'll do about 10mph, not sure Punch engines are known for putting out huge horsprs.


A hamster wheel?
Can I have some of what you're having 😂

[LowStandards]

There is another option

Use the 2 barrow wheels and build an ever cooler version of the Welbike ParaTrooper bike




We have a 140cc PitBike engine, so it would be hilarious, proper 5 speed, manual clutch jobbie

I've played with PotatoShop and I reckon with short bars and maybe a cafe seat it would be nuts





Yeah, it's not quite the vintage mini bike, but If we kept the frame tight around the engine and use the 10inch wheels (pretty sure the Welbike has 12s) it would still be tiny

[slackerTHEpinstriper]

Like this Lambretta sprinter with "rear set" pegs and brake set up on the rear axle

[slackerTHEpinstriper]

[LowStandards]

Right!

The plan has been made

I'm building a vintage 'Tom Thumb' mini bike using the Suffolk Punch engine


The frame we'll be copying




Now my wheel and tyre combo are a little bigger than the ones shown. They're still 4 inch wheels, but the tyres are a little bigger in diameter and width

Vintage bikes seeming use an 8.5 inch tyre with a 2.5-3 inch width, the ones I have are 10 inch diameter and 4 inch width. So it will still look the same, but i'll have a bit more comfort and ground clearance.


I've 'mocked up' the length i'd like it to be - I say mocked up, place a wheel either side of an engine isn't taxing - and hopefully I can keep the axle centres at 600mm like they are here, or hopefully even shorter.




Some pictures of the powerhouse, no doubt just for my reference, but hey.









The engine dimensions (again for reference)

310mm from engine mount to top of sparkplug
300mm width from pull start to end of crankshaft
270mm front to back (including carbs and exhaust)
110mm engine plate width, you can set the engine between frame rails to a depth of 18mm to lower engine
36mm crankshaft length

The engine is 75cc and makes roughly 1.1hp at 3000rpm

They make the most awesome sound at idle as can be heard in this video @ 35 seconds in




I think it will probably do around 12mph - perfect

[brachunky]

Please stop filling my head with this  I have a 5.5hp side shaft motor on a rotorvator which is would do

[LowStandards]

Sept 12, 2023 20:09:41 GMT brachunky said:

Please stop filling my head with this  I have a 5.5hp side shaft motor on a rotorvator which is would do

Certainly don't Google tiller racing

[LowStandards]

Was having a look online as you do and was marveling at how short these things are, mine at 600mm is larger than I wanted, but it just wouldn't fit any shorter.


Hold up, i'm an idiot, lifted the engine up to its final height and rolled the back wheel under the carb


I've now got an axle to axle length of 540mm - sweet

[OAY842F]

Nearly finished then! Excellent, love your "little" builds!

[LowStandards]

Managed to grab a quick ten mins at lunch and did all the CAD work


And by CAD work, I do of course mean, laying everything on its side on an old piece of kitchen worktop and drawing round it




I then looked at the picture of the frame i'm making. Nice curve at the back, what do we having in the garage, ah the Scamp steering wheel.

Drew round it to get the main shape of the frame, then filled the other bits in with a ruler.




So, it's tight, real tight, but these bike are meant to be.

I'll have to get creative with the jackshaft location to gear it down, but I think we're good to go

[Davey]

Just as a heads up.

I am the boss man for the below, if you want to explore sizes let me know. (Special RR Discount of course.)

www.bigtyres.co.uk/tyres.html?rim_size=836&stock_only=1

[merryck]

Nov 7, 2023 13:18:35 GMT Davey said:

Just as a heads up.

I am the boss man for the below, if you want to explore sizes let me know. (Special RR Discount of course.)

www.bigtyres.co.uk/tyres.html?rim_size=836&stock_only=1

*Clicks on a link to a site called Big Tyres*

*Is shown a lot of very small tyres*

Hang on a minute...

[Davey]

Nov 7, 2023 13:44:25 GMT merryck said:

Nov 7, 2023 13:18:35 GMT Davey said:

Just as a heads up.

I am the boss man for the below, if you want to explore sizes let me know. (Special RR Discount of course.)

www.bigtyres.co.uk/tyres.html?rim_size=836&stock_only=1

*Clicks on a link to a site called Big Tyres*

*Is shown a lot of very small tyres*

Hang on a minute...

You are quite right, we should be called ALL OF THE TYRES!

Better?

www.bigtyres.co.uk/tyres.html?rim_size=520

[grizz]

Nov 7, 2023 13:18:35 GMT Davey said:

Just as a heads up.

I am the boss man for the below, if you want to explore sizes let me know. (Special RR Discount of course.)

www.bigtyres.co.uk/tyres.html?rim_size=836&stock_only=1

I wonder if glenanderson would be able to use your knowledge and access to weirdness’s

[Davey]

Nov 8, 2023 11:07:14 GMT grizz said:

Nov 7, 2023 13:18:35 GMT Davey said:

Just as a heads up.

I am the boss man for the below, if you want to explore sizes let me know. (Special RR Discount of course.)

www.bigtyres.co.uk/tyres.html?rim_size=836&stock_only=1

I wonder if glenanderson would be able to use your knowledge and access to weirdness’s

My knowledge and weirdness is open to the entire RR community. Oh. I can also help you out with tyres...

[glenanderson]

Nov 8, 2023 13:34:26 GMT Davey said:

Nov 8, 2023 11:07:14 GMT grizz said:

I wonder if glenanderson would be able to use your knowledge and access to weirdness’s

My knowledge and weirdness is open to the entire RR community. Oh. I can also help you out with tyres...

I am aware of the BigTyres website. I’ve had a bookmarked page for tyres for my Austin for a while. I was not aware that the boss man there was a resident here though; that’s good to know. 👍👍