Smallest lightest engine?

[dsj1979]

Hi,

I was just wondering what the smallest lightest diesel engine you can get is? I have a Trojan Trobike which needs a new engine...... Although I'm 99% sure there wouldn't be a diesel suitable for it I thought I'd check as I'd love a diesel bike!

Thanks,

Daniel

[gilburton]

I think you are going to struggle there. Most of the 6/10hp industrial engines are about the same size/weight and although I think they have been fitted to minibikes before do you really want to damage such a historical machine as this lol

[dsj1979]

I think you are going to struggle there. Most of the 6/10hp industrial engines are about the same size/weight and although I think they have been fitted to minibikes before do you really want to damage such a historical machine as this lol

I figured it would probably not work.... but incase there was a tiny 3hp unit somewhere....

I've got a few Trobikes, I want to make one into a more useable bike. I still won't cut or weld any of the bike (wouldn't want to damage a classic), anything would have to be bolt in. I'm looking at mini bike engines at the mo, cheap cheerful and easily replaceable. The big problem is the drive is on the other side to normal - chain on the right side of the bike. I've found a gearbox unit which reverses the drive so hopefully all will be good. As I'd love a diesel bike though, killing two birds with one stone I thought it was worth a punt incase a tiny diesel existed.... not that I thought it likely!

[dsj1979]

I just realised I've been lurking on this forum since 1998.... and this is my first post!

Anyway.... if such a diesel doesn't exist (which is most likely), as this forum is full of clever / insane people; does anyone know any bike / stationary engines where the pto runs clockwise instead of the usual anti-clockwise which could be suitable for my trobike? Otherwise it'll be the mini bike engine with reverse drive gearbox unit.

[gilburton]

What engine is in it now Clinton?? Most of these minibikes seem to have the drive on the left. Can it not be just flipped over?? and maybe a bracket for the brake welded on?? It would make life simpler in your search as most engines are counter clockwise looking at the drive shaft. No doubt you'll get some info from someone.

[dsj1979]

Yes a Clinton... but not too reliable and part fairly impossible to get; that's why I like the idea of another bolt in engine. I could flip the wheel and weld on another bracket for it... but .... I really don't want to have to modify the bike. I have found a 49cc motor with a gearbox (mini moto one) that reverses the drive. It's a reduction gearbox which means trying to change that, and modify a new sprocket for it. Though if anyone knows of a reverse engine? Easiest would be to flip the wheel then anything would be easy..... but what's the fun in that!

[gilburton]

I've had a look at pics of the trojan and the brake plate just appears to be a bit of tube?? Surely if you're installing another engine anyway a small tube welded on the other side(leave the original on) would not be out of place and could easily be removed.Alternatively you could make up a clamp on piece of tube?? That way you have a vast choice of small mower type engines to choose from. Just a thought! Is the bike road legal or for off road use? If it's off road do you need a rear brake?? The original "garden" versions didn't have any brakes!

[pietenpol2002]

There are in fact plenty of small diesels built in China such as the 3 hp example below. Unfortunately, emissions standards likely precludes ever importing one. But, it would make for a great looking little sloper that might well fit in that frame.

http://www.12got.com/product/1079449719 ... sel+engine

[dsj1979]

I've had a look at pics of the trojan and the brake plate just appears to be a bit of tube?? Surely if you're installing another engine anyway a small tube welded on the other side(leave the original on) would not be out of place and could easily be removed.Alternatively you could make up a clamp on piece of tube?? That way you have a vast choice of small mower type engines to choose from. Just a thought! Is the bike road legal or for off road use? If it's off road do you need a rear brake?? The original "garden" versions didn't have any brakes!

I really didn't like the idea of modifying the frame.... not really sure why. But... that would make it so much easier; think I should get that out of my head. I can buy a mini bike engine new for £50

Yes it's a road legal bike! 1962! The last time it had an MOT the guy said he felt bad taking the money off me.... 2 mins and it's tested. No electrics, a bulb horn, no suspension, no bushes.....

[gilburton]

If you made up some engine mountings that would bolt to the original mounting plate it could easily be returned to original if required

[dsj1979]

There are in fact plenty of small diesels built in China such as the 3 hp example below. Unfortunately, emissions standards likely precludes ever importing one. But, it would make for a great looking little sloper that might well fit in that frame.

http://www.12got.com/product/1079449719 ... sel+engine

That's excellent! Anymore like that? Do you know anything about size, weight etc.? How do you start it? I just thought.... if it's two stroke diesel, then it could run anti-clockwise or clockwise? Maybe? I wonder what the fuel consumption is like?

Great find!

[gilburton]

Don't forget it's in China and you'll have to pay postage and customs(assuming it's any good of course)

[gilburton]

You're in luck if the price is ok??? It's a 4 stroke though so you'd still have to flip the wheel.
http://www.ebay.co.uk/itm/168F-3Hp-RECO ... 53eb62252d

[dsj1979]

Don't forget it's in China and you'll have to pay postage and customs(assuming it's any good of course)

Disposable mini bike engine engine for £50 is easiest... also the lightest.

4 Stroke would be good... but heavier and engines probably too big.

Diesel above is great as... it's diesel.. but probably bloody heavy and don't know how big it'll be... and most expensive.

[dsj1979]

You're in luck if the price is ok??? It's a 4 stroke though so you'd still have to flip the wheel.
http://www.ebay.co.uk/itm/168F-3Hp-RECO ... 53eb62252d

Another good find! I'll have a measure up and see if it'll fit......

I knew this was the right forum to ask!

[gilburton]

The dimensions are on there and these guys also do pit bikes so might be sympathetic to your quest?? Some nice little petrol engines on there which might suit . Cheaper as well!
http://www.ebay.co.uk/itm/2-5Hp-LT154Q1 ... 416c655a74

[dsj1979]

The dimensions are on there and these guys also do pit bikes so might be sympathetic to your quest?? Some nice little petrol engines on there which might suit . Cheaper as well!

I'm going through them now, great find thanks! At those prices I'd much rather have a 4 stroke than a 2 stroke. The diesel is surprising though, only 20kg!? That's very good!

[gilburton]

You'll need a clutch as well!

[dsj1979]

That's the one hopefully easy thing, a go cart / mini bike centrifugal clutch!

[gilburton]

Good luck then and if you go the diesel route maybe you can post some pics?

[dsj1979]

I must say, my favourite is that 168f engine - great find! It's light enough and I'm sure I can make it fit. I think I'm going to have to give that a go unless measurements are completely off...

[dsj1979]

Well.... I've done some measurements and I think the diesel is probably just a bit too wide .... One the Trobike the middle plate has a width of 19 cm, the pegs are 37 cm wide. It would take up the whole frame mostly but length and height is doable, it's the width. The width of the engine is 36.5 cm.

[gilburton]

It does say "shipping size" so I presume the engine is actually smaller?? You could email them.One other point can you get a 25mm clutch?? most of the ones I've seen on ebay are 3/4" or 19mm?? Just a thought.

[dsj1979]

Despite spending a lot of time looking at it, I didn't pick up the shipping size. I'll email them and check! I've tried to look on google for full specs etc. but to no avail...

The PTO will stick out further than the wheel sprocket so I would have to make a heath robinson style set-up anyway; I suppose a 25mm sprocket on the PTO, turning another shaft rearwards on the bike, maybe a clutch on this shaft and sprocket to connect to the rear wheel sprocket. Now, if I wanted to keep the wheel sprocket on the right side of the bike (like it currently is), how best to reverse the drive. I guess two shaft / sprockets together would do that - do you know of any bits or parts that could be cannibalised to do that?

[dsj1979]

The 168f engine isn't on their website, I've asked if they have the specs, size etc. and if they have any smaller engines or have access to.... will be interesting to hear their response.

[gilburton]

maybe you could use old cycle parts??
If you enter bike jackshaft in to google and look at the images you will get lots of inspiration. Unfortunately a lot of minibike stuff is in the US.

[dsj1979]

Looks like there's all sorts of things off the shelf for jackshaft..... that's my next hour sorted on google!

[gilburton]

A lot will depend on what engine/clutch you get and cost /how much engineering you can do! If you can lay your hands on a small engine cheaply inc a clutch eg goped/pit bike/mower then to be honest I would go that route and either add a jackshaft to take the drive to the right or just flip the wheel. What size is the clutch on the Clinton?? Could you re use that?? I know it wouldn't be diesel but simple is best!
You could even use a complete Honda C50/70/90 engine or one of the chinese clones which gives me an idea!!
Plenty of these on ebay and it's all there.This is 4 stroke but there are some 2 strokes as well!

http://www.ebay.co.uk/itm/Motorised-Bic ... 4ac1e6caf5
this is on sale now but appears to have a shaft??
http://www.ebay.co.uk/itm/300871283159? ... 1423.l2649
Also if you could get hold of a Jawa moped the drive is on the right!
http://www.ebay.co.uk/itm/121078413150? ... 1423.l2649
http://www.ebay.co.uk/itm/171001128437? ... 1423.l2649
And finally I suppose the drive direction is wrong??
http://www.ebay.co.uk/itm/321084830964? ... 1423.l2649

[dsj1979]

Thanks for the links. I'm certainly no engineer (unfortunately), I just like playing... Unfortunately the clinton engine is the wrong way version.

I bought a mini bike before hoping to use the bits for mine, I stripped it down yesterday but it doesn't help as much as I hoped it would. The engine rotation is Anti Clockwise but a reduction gearbox reverses the drive - perfect! I stripped down the gearbox yesterday and I can't alter the reduction ratio of 5:1. This means I would need a 60T front sprocket which wouldn't fit... bugger.

The engines are these:

http://www.petrolscooter.co.uk/spare-pa ... gines.html


Next option, reversing the engine. A few ways to do this....

1) Reposition the flywheel or crankshaft keyway so in reverse the magneto would be correctly timed, or reposition the ignition coil to do the same. I don't know how easy it would be to make a new key way..... I assume just slow and fiddly. That would work, but in reverse the fins wouldn't aid in cooling the engine. I don't know how vital that is?
I would also need to get the starter to turn it the other way - hopefully easy enough.

2) Leave the engine running as is, but (somehow) move the starter to where the clutch currently is, and (somehow) take the driver off the starter end of the crankshaft. The engine would be running in the direction it was intended, I'm just not sure the crank would hold up to having the drive taken from the wrong side?



Other than that, it's swapping the wheel round, or using a jackshaft. In that case, I would rather then use a 4 stroke petrol engine - or a diesel! No mixing of fuel and more reliable. The guy who sells the 168f also sells:

http://www.ebay.co.uk/itm/5-5Hp-LT160Q1 ... 41700e1987

http://www.ebay.co.uk/itm/2-5Hp-LT154Q1 ... 416c655a74

http://www.ebay.co.uk/itm/2-5Hp-LIFAN-1 ... 417011bdbb

[gilburton]

Well I would take the easy route and use a shaft. If you made up a flat plate type mounting(similar to the bicycle kit) but make it a bit longer with upright supports each side at the rear to take a shaft/bearings. This could then be mounted on top of your original mounting if you want to keep the bike original?? Looking at the bicycle kit it looks to have a small shaft protruding out with the sprocket.Maybe you could get something similar but extend this shaft a bit using a small coupling designed for electric motors?
I find http://www.bearingboys.co.uk to be very good for bearings/sprockets/bushes. You can get most stuff on Amazon as well and obviously your local bearing factor. You could try kart places for shafts etc. But I actually got my jackshaft kit from the US as you don't seem to be able to get them over here. You can get them made up though.
Enter kart jackshaft kit and once again look at images and wonder at how lucky the US is.
This is on ebay UK but still the US. It's similar to mine but I used pillow block bearings as I needed something stronger should be ok for you though? http://www.ebay.co.uk/itm/5-8-35-Jacksh ... 0983873882