Anyone added an engine to their MTB?

Bike-Rich

Was a bit unsure where to post this, did a search but could not find much.

I see engine kits for 26" wheeled bikes are becoming popular now, 80cc kit is priced at around £160 and apparently includes everything (apart from bike) needed.

I know it would not be legal to use on road but I have a couple of old bikes just laying around so i'm thinking i might give it a go,

Anyone done one?

thistle_

I saw it done on an Apollo Slammer about 7 years ago.

It wasn't a purpose made kit, rather an interesting old fellow who had attached a motorbike engine between the down tube and the top tube to 'give him a bit of a boost on the hills due to the shrapnel in his leg from the war'

cooldad

I built one in the 70's using an old WW11 motor that used a drum to rub on the back wheel, although we didn't have actual MTBs in those days. It was just an old bike, with the seat tube chopped out and the motor used as a structural member (as used years later F1 cars and other fine vehicles.)
It was a laugh for a while, but really rather sh1t.
I've looked at the bits on Ebay, but I think they'd be rubbish off road, illegal on road.

PashleyRider

Me and a mate did this when we were 11, got an old strimmer and a shopper bike, welded on some engine mounts and a bmx sprocket onto the NDS of the rear sturmey and away we went! Pedal to get it going then open up the throttle and whizz around!

A proper engine on a MTB does sound like a cool idea though, I would quite like to try it

cooldad

Or one of these
http://www.ebay.co.uk/itm/MATTEL-VRROOM ... 2ec550bf4a

MTB noob

I am thinking of making a road-legal(ish) one. I have a 2200W (2.9hp) 24V DC electric motor which offers a huge amount of torque in my garage and am thinking of adding it to my scrap bike. I will have a dial to restrict the power to the legal limit of 200W for road use and back to <2200W when i'm off-road.

Has anyone ever done it with an electric motor yet?

The Rookie

cooldad wrote:

I've looked at the bits on Ebay, but I think they'd be rubbish off road, illegal on road.

Illegal in any public place unless you have third party liability insurance....which you may find hard to get

twonks

MTB noob wrote:

I am thinking of making a road-legal(ish) one. I have a 2200W (2.9hp) 24V DC electric motor which offers a huge amount of torque in my garage and am thinking of adding it to my scrap bike. I will have a dial to restrict the power to the legal limit of 200W for road use and back to <2200W when i'm off-road.

Has anyone ever done it with an electric motor yet?

I'd have a think about batteries and cabling to run that sort of motor.

2200W @ 24V will need around 100A and a battery to provide that for any length of time to deem it useful for a bike will be massive and weigh a tonne.

bobs bikes

have a look at www.conv-e.com
they have the road legal kits for any bike.

we had a guy come in with a petrol engine on his mtb a while back. he used it to rag about his farm on!
i have a pic here, ill try and get it uploaded.

MTB noob

Ive done the math now and if I use my 2200W motor (roughly 10kg) and if I use two 13Ah batteries (4kg each), I can run it at 200W for just over 3 hours. However if I use two 30Ah batteries, I can run the full power at 40 minutes if I ever need it. It doesnt sound much but thats nearly 30 miles on one charge at full power on the flat. If I run it at 1000W (sufficient to hold 30mph) it can run for 46 miles. All I need to do now is to make the frame to attach it.

The Rookie

Check the legality though.....most vehicular rules apply in any public place, as yours is too powerful to be an assisted bicycle it would then be classed as an electric vehicle requiring third party liability insurance as defined in the road traffic act, not 100% if it will apply off road, but you want to be sure - 6 points and a £200+ fine isn't nice!