Petrol powered mountain bike legallity?

[W124Bob]

I spotted a fairly ordinary mountain bike recently fitted with a very small petrol engine , aprox 1litre petrol tank on the crossbar but the engine was tiny(but audible). The rider had no helmet , no lights and no reg plate. So what is the legallity of this ?

[CAPP0]

Zero, I would think!

But whether (s)he gets stopped or not is another matter.

There used to be something called a Cyclomotor (sp?), there were two types, one had a tiny engine in the frame but looked just like a regular pushbike, the other had the whole thing built into the rear wheel - very neat. But I'm pretty sure they had a number plate so they must have to be insured etc as well.

Edited by CAPP0 on Saturday 4th November 12:36

[TooMany2cvs]

It has an internal combustion motor below 50cc, it's a moped. It needs to be registered, it needs to be insured, the rider must have a licence and helmet, etc etc. All the usual legals, exactly the same as next door's suicidal 16yo's Kymco hairdryer. If it doesn't, then it's as illegal as any mini pitbike.

If it's electric, then there's a specific exemption below a certain power level, but that doesn't apply to internal combustion.

[gazza285]

Cyclemaster.



Probably no faster than a modern e-bike.

[TooMany2cvs]

gazza285 said:

Probably no faster than a modern e-bike.

I have a VeloSolex. It's slower (and stter in every possible way) than anything pedal-powered yet, legally, it's a moped.

[InitialDave]

There was a guy round here I saw with that kind of setup, but not seen it for a while. Not sure if he's broken it, crashed it, or plod have had a chat with him.

Not at all legal, but he was nowhere near as annoying as the scummy kids on field bikes that you occasionally see blatting wherever they want. Actually, not seen one of those in a while, either, so maybe the police did something about the issue.

[anonymous-user]

I road a Solex around the Luberon in 1983. It was rubbish but cool!

[Vaud]

Breadvan72 said:

I road a Solex around the Luberon in 1983. It was rubbish but cool!

I rode one round my French exchange students garden in 1987.

I say “rode”. I mean, “went fine in a straight line and then crashed it into a wall”

[Cold]

[Red Devil]

https://www.youtube.com/watch?v=OjiOmdS3yNA
The engine is a KJ-66 micro gas turbine engine.
Designed by Kurt Schreckling and Jesus Artes (hence KJ)
Mainly used by model engineers in RC aircraft and boats.

If you're going the powered assistance route, don't be a pussy.
Live dangerously. - https://www.youtube.com/watch?v=bKHz7wOjb9w

[TooMany2cvs]

Red Devil said:

If you're going the powered assistance route, don't be a pussy.
Live dangerously.

Well, quite.

https://www.youtube.com/watch?v=YamiV2DR_r8

[grunge]

W124Bob said:

I spotted a fairly ordinary mountain bike recently fitted with a very small petrol engine , aprox 1litre petrol tank on the crossbar but the engine was tiny(but audible). The rider had no helmet , no lights and no reg plate. So what is the legallity of this ?

its a motorbike

[Prizam]

Serious answer.... it depends. but probably not.

There is provision in law for mechanically assisted bicycles to be legal. however, they must only be assisted (Be able to pedal still) and have a power output no greater than 2,000w. Unlikely for any engine bigger than about 20cc.

[TooMany2cvs]

Prizam said:

Serious answer.... it depends. but probably not.

There is provision in law for mechanically assisted bicycles to be legal. however, they must only be assisted (Be able to pedal still) and have a power output no greater than 2,000w. Unlikely for any engine bigger than about 20cc.

They must only be ELECTRICALLY assisted. Internal combustion is explicitly excluded from that. My Solex is 0.75bhp, 560w, and is definitely pedallable (as you have to to at the first sign of a hill) - and must be registered/taxed/insured etc.

Also, the electric assistance power cap is much lower than 2kW - it's only 250w.
https://www.gov.uk/electric-bike-rules

[foxbody-87]

I had a Honda GX35 on my pushbike (so much quieter than these nasty eBay kits) but yes definitely not road-legal. Fun though!

[Boosted LS1]

Are the regulations different from off road or on road or in a field etc?

[TooMany2cvs]

Boosted LS1 said:

Are the regulations different from off road or on road or in a field etc?

The only regulations are those that apply on a road.

You can build and drive/ride whatever the hell you like off the road. Providing, obviously, you have the landowner's permission to be there.

[Vaud]

TooMany2cvs said:

The only regulations are those that apply on a road.

You can build and drive/ride whatever the hell you like off the road. Providing, obviously, you have the landowner's permission to be there.

And it must be private land, closed off from "public access"?

[TooMany2cvs]

Vaud said:

TooMany2cvs said:

The only regulations are those that apply on a road.

You can build and drive/ride whatever the hell you like off the road. Providing, obviously, you have the landowner's permission to be there.

And it must be private land, closed off from "public access"?

Not necessarily "closed off from", but certainly with no expectation of public vehicular access, else RTA applies.

I think you'd be fine in a field with a footpath through, but not down a green lane.

[Decky_Q]

Even stricter in NI, there are no exceptions here so even a 1w electric assisted bicycle is classed as a motor vehicle, and have all the associated obligations.