smallest engine First post

[gordon160]

Hi all hope somone can help?
I would like to make a bike useing a small diesel engine along the lines of a moped.
Does anyone know the smallist usable diesel engine I was hoping about 100cc what make & how to obtain one would be helpfull
If not a moped may be some thing like a VELOSOLEX if you dont know what a VELOSOLEX looks like check out http://www.bullnet.co.uk/
check out technical information less than one hp or 0.58kw please can someone help here,s hoping? gordon160

[Stuart]

Hi Gordon.
Y'know I've been to the Bull Electrical shop a few times over the years. It used to be in Portland Rd, brighton right? Very interesting shop if I remember correctly. Forget what I bought there.

A small diesel will give you so little HP that it will hadly be worth using. I seriously doubt you'll get any usable power out on anything as small as 100cc. We do have the odd scooter on the site if you look hard enough.

But yeah, if you wanna go the bicycle route then maybe you could swing it with a micro engine...

Regards

[Byrdman]

I believe the Yanmar L48 is one of the smallest, industrial, air cooled diesels out there. It's rated at 3.4 hp and that's barely enough power to use as a starter for other small diesel engines!

Why are you trying to go so small?

[gordon160]

Hi I am looking for a really light weight bike because I am disabled I have a bad back
However a small diesel engine should get high miles per gallon a good enough reason in its self to try and make one
Hi I am looking for a really light weight bike because I am disabled I have a bad back
However a small diesel engine should get high miles per gallon a good enough reason in its self to try and make one
In the past there used to be two stoke diesel engines about although nearly all now seem to be four stroke Perhaps its possible to convert a two stroke motorbike engine to diesel maybe a BSA bantam 125cc or similar
If all else fails I was thinking about converting a trippi with about the size engine you mentioned in your reply,
A trippi can be found at http://www.nippi.co.uk/ thanks for your help and interest gordon160

[Rick-II]

Somewhere along the way, I cam eacross a news article (online) about a guy in India building up micro-diesel engines. As I recall, they were down around 30-40cc. His intent was to be able to put them on bicycles and get REALLY great mileage out of them. I think they only made around 1-1.5 hp .

[gilburton]

the diesel Lohmann was only 18cc and was an autocycle or cyclemotor

[Byrdman]

Hi I am looking for a really light weight bike because I am disabled I have a bad back
However a small diesel engine should get high miles per gallon a good enough reason in its self to try and make one
In the past there used to be two stoke diesel engines about although nearly all now seem to be four stroke Perhaps its possible to convert a two stroke motorbike engine to diesel maybe a BSA bantam 125cc or similar
If all else fails I was thinking about converting a trippi with about the size engine you mentioned in your reply,
A trippi can be found at http://www.nippi.co.uk/ thanks for your help and interest gordon160

Gotcha. I understand the reasoning and it makes even more sense now. A diesel scooter type bike would be fun, especially running on a vegetable oil blend!

I think a gas - diesel, two stroke conversion would be a fun project but it might be more work than you realize. Obviously component strength is the first concern as diesel cylinder pressures are two to three times what a comparable gasoline engine endures.
The second obstacle would be the fuel system. Somehow rigging an injection pump would be tricky to say the least.

Maybe grafting that small Yanmar to the automatic clutch? That might be the safest plan.

[andrewaust]

I also think a small Yanmar, or one of those small Yanmar clones would be even better as they are really well priced and seem to offer the same performance and reliability.

You could rig it up to a small scooter with a CVT and away you go. Guess the top speed would be good for 60 K/hr / 38 m/hr.

I think the Yanmar/clones start from around 200cc's and would give you the power similar to a 125cc petrol engine.

I don't think you'll ever be able to convert a 2 stroke petrol engine to diesel and have it run reliably, the crank, big end etc just won't handle the stress. Then you have the problem with lubrication etc.

I think your best bet would be a little 4 stroke.


All the best with it!




Cheers


Andrew

[LocomotiveBreath]

Maybe look for an old complete Lohmann set up, but they are quite rare but show up on eBay from time to time in the $800-$1500 dollar range last time I looked.

http://my.opera.com/bhtooefr/blog/show.dml/91951

Good luck,
Dave

[stormcoat]

If I recall correctly, the Lohmann engine was not dissimilar to the model aircraft engines of the time. It was, in effect, identical to a two stroke petrol engine, even down to a crude carburettor, which only had provision for fuel control, not air.

The compression was variable, controlled by a screw arrangement in the head, with which the person operating the engine could wind, up or down, a counter piston, thus varying the size of the combustion chamber. Fuel/air mixture, complete with mixed in lubricating oil, was sucked in to the crankcase and transferred into the combustion chamber by the descending piston, as in a normal bike two stroke. Ignition occurred largely by virtue of a sufficient quantity of nitrate additive in the fuel itself. In other words, the fuel/air mixture detonated under pressure, in the same way that a petrol engine would "run on" with the ignition switched off, if it was coked up or being run on paraffin. The term "Diesel Engine" was really a misnomer, for none of Dr Diesel's patents were incorporated into either the design or the principle of these engines, save for the lack of any means of ignition other than the temperature increase generated by compression. Also, the fuel mixture used was comprised of petrol, paraffin, nitro methane and castor oil, not diesel fuel in the conventional sense.

It is still possible to obtain small engines of this kind, for model aircraft. Today, most of them are of the glo plug variety, and do not incorporate the variable compression screw. However, I am sure that it would be possible to incorporate such an engine as an assister to a pedal cycle, if you were determine to. The obvious advantage over a petrol engine is the absence of any electrical apparatus. Even glo plugs only need to be energised while starting.

Richard Powis
Essex, England.

[gordon160]

Hi thanks for your help
40 years ago I had a 2.5 cc ed racer diesel engine, which I bought for a model aircraft I crashed that aircraft and another but kept the engine this kept me fascinated until my first motorbike it was then forgotten about.

I used to start it at least once a fortnight for years
I fitted a lock nut on the compression screw, which had the effect of setting the compression
To peak revs
Leaving just the needle valve for the fuel to adjust
However each new can of fuel required the compression screw to be adjusted for peaked revs again, too much compression slowed the engine down, as did not enough compression

To answer a few points in the letters you can run two strokes or four stroke petrol or diesel
Engine with a carb or fuel injection all the engine needs is the correct amount of fuel to air mixture
If you was worried about component strength of a 125 cc 2-stroke engine you could make a 175cc bantam
Engine into a 125cc engine by sleeving the 175cc engine down to a 125 piston

You would have to cut out clearance in the sleeve for the con rod of course that’s presuming the piston height above the gudgeon pin is correct it may pay to fit an extra compression ring, as well

Perhaps a better idea would be to try to convert a 50cc 2 stroke mini moto engine to a semi diesel they are plentiful and cheap unfortunately I have enough projects to do for at least two or three years
If I make one work then ill send an email to tell you about it don’t expect it for two years at least
If you’re interested in semi diesels try the following link

Link http://www.bolinder-engines.info/ click enter
Click vintage engine enthusiasts
Click profile Andy Talbot
Click semi diesel bolinders [images]
Scroll down to seventh picture to see silver white blow torch used to start engine
Or try this if it links http://www.bolinder-engines.info/enthus ... iesel.html
Also of interest
http://en.wikipedia.org/wiki/Internal_combustion_engine tells you about five and six stroke engine etc


Thanks again gordon160

[oldbmw]

Think what would be ideal is a diesel wankel engine. would do away with much of the vibration, and probably have enough power for a bike.