Want to Convert Motorcycle to Woodgas, NEED ADVICE!

Projects
#1

Hello,
I am seeking advice to help build a wood gasifier around a motorcycle. That’s right a big-ass wood gasifier around a motorcycle, not in a trailer or side car. I DO NOT want to build a charcoal gasifier, I want to take on this challenge. I know it might be heavy and awkward looking but I intend to balance it as best as possible. I have built a wood gasifier before and have a series on youtube called “Wood Gasifier Build For Dummies” my channel name is TontoBob. I will document this whole build as well for public knowledge if I find that it is do-able.

I have been searching craigslist for the right motorcycle, I want it cheap enough to weld brackets on the frame and not care($1000-$2000), powerful enough to hold me (170 lbs) plus a wood gasifier with full hopper and all (200-400??? Lbs??), fairly fuel efficient for less wood consumption, lower RPM than 8000???, and if possible go 100mph on gas so I can hopefully get good mph on wood, not necessary though. So far I have found many 1980’s Honda Rebels, Honda Shadows, Suzuki GS bikes and things like that. I have not decided yet but here are the specs for a 1988 Honda Shadow VT800:
ENGINE SPECS

Engine Type: 798 cc, 4 Stroke - Liquid Cooled - V Twin
Engine Bore and Stroke: 79.5 mm x 80.6 mm
Valves 3 valves/cylinder
Claimed Horsepower: 74 hp (55.2 kW) @ 7500 rpm

Transmission type: 4 speed
Final Drive: Shaft

MISCELLANEOUS SPECS

Tire - Front: 100/90-19
Tire - Rear: 140/90-15
Brakes - Front: single disc

DIMENSIONS

Fuel Capacity: 12.5l
Dry Weight (without fluids): 225 kg (496 pounds)

I think this is a likely bike for me to choose or one similar in CC’s or HP and engine type.

So with that all said, can I ask for some advice on possible dimensions for hearth zone, reduction zone, air nozzles, biochar zone, and anything else that might help? I am planning on mounting the gasifier on the back of the motorcycle, 3 conical cyclones on the right side, an aluminum radiator on the front, 2 fire extinguisher filters and a final cyclone on the left side before snakeing pipe to a homemade carb into the engine.

I am open to ALL suggestions even if its telling me this will never work, but I want an explanation in that case to. The thing that trips me up on this is the high horsepower, high RPMS, and odd engine dimensions compared to a truck or small engine that gasifiers usually are built to run. Thanks!!

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#2

If you want to see the last video in my youtube series to judge my level of competence, here is a link to that:

I Intend on using a similar design for the main unit just shorter, want to use a large propane tank again as the outside shell which I will wrap in high temp insulation. Thanks!!

#3

Hi Brenton!

I see no reason why this shuldnt be possible to make! I am a big fan of small woodgas setups. With the technology we have today there is no need for big heawy gasifiers. My recent project is a gasifier for a car, mounted on a towbar, the whole settup (full gasifier, filter, cooler and platform) weighing 75kg (150 pounds). It has no problem pushing a 109 hp car down the road. You can check it out in the Project category, Leitinger wood gasifier.
Althugh a charcoal gasifier wuld be a much easyer, cheaper and practical way, a wood powered motorcycle is a chalenge for sure, but with the right settup this will be a great project!
First, you need to know your gas consumption. The simplest way is to test drive the engine. You can need to know what rpm the engine usualy drives at. Thain, based on that, you calculate your max gas consumption and gasifier dimensions. The other big factor is fuel. Chunks or chips?
Hope to see some progress soon! Be sure to post some pictures!

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#4

Welcome to the site Bob. 1st, I think I heard you mention fema, forget anything from a fema design, they are tar producers. 2nd, read everything you can on this site,lots of people here d.o.w. every day. 3rd invest in a premium membership to this site, you’ll never regret it.

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#5

I will check out your post on the leitinger wood gasifier. Do you have equations for calculating gasifier dimensions or are they in the FEMA handbook? Thanks!

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#6

I am definitely not going to build a FEMA, I plan on a fairly traditional imbert. I tried to look up past forums on woodgas motorcycles but found them not very useful as everyone just says “go with charcoal.” Thanks

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#7

Max Gasman has some very usefull equations for gasifier sizeing, there are allso some in the DOW library.

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#8

Hello,
The Honda Shadow VT800 has two carburetors, correct? Are you planning to remove those and build a manifold to go between the front and rear cylinder, with the required air and woodgas mixing valves? If so, then will you lose the ability to run in the gasoline only, or in the hybrid mode. Woodgas only on a very overloaded heavy bike might be hard to push home if something breaks loose and the system is no longer air tight. I noticed your gasifier(s) have not been making tar-free gas, and this has been sticking up the blowers, and blackening the filters. The big advantage of well made and properly sized charcoal is that the tar has been driven off in the charcoal retort, which leads to a much lighter system on the motorcycle with smaller filters, no heavy cooling racks, and perhaps only one cyclone.
Did you mention using bark in your wood gasifier? Bark (in my opinion) is best used to heat the retort that makes charcoal. Review the postings of Koen Van Looken, Gary Gilmore, Bruce Southerland, and Martin Payne (Honda Motofier on Charcoal). Making charcoal is an Art, and it is possible to make lousy charcoal. Gasification runs on charcoal, whether you make it on the fly in a wood gasifier, or make it in a retort and then sort through it and get it properly sized for a charcoal unit.
The specifications listed for the Honda engine is showing peak power at 7500 rpm, on a bike with only four speeds. Woodgas flame fronts can maybe handle 3600 rpm. I doubt it will do 7500 rpm. The 4 speed Honda Shadow will have a very high ratio 1st gear, and will need lots of clutch slipping to get a fully outfitted wood gasifier moving. It is too bad old Harley Davidson Motorcycles cost so much, because they have one carburetor sticking out on the side, heavy duty frames, and an antique engine that pulls like a tractor at low engine speeds. The 1949 Harley I owned even had a timing control on the left handlebar. The retarded timing was good for kick-starting a large displacement motor, so humans did not suffer from a sore leg.
I suggest a charcoal gasifier unit for a motorcycle because it can be much lighter in weight. Good luck, and keep us posted on your progress.

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#9

Hi Brenton,
As you mentioned traditionally a wood fired gasifier for motorcycle is placed on a sidecar or they use a trike. The weight distribution of that mass will be difficult. I think closest to your goals would be Stephen abadesses Victoria type hearths. He has some good dimensioning on his pages. Having said that if the goal is to make it work well not just function you really should reconsider charcoal. There is a remarkable weight difference between the two systems and an ease of use. Driving the bike you have a lot on your mind without worrying about a dramatically changed centre of gravity and overall mass. My atv, koen’s trike and a few more are already here. Having said my peace good luck. I’ll look in with interest…
David Baillie

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#10

One other thing… lt might be a good idea to consider puting the settup on the side of the motorbike. I wuld put gasifier on one syde and filter/cooler on the other, to lower the gravity point. Sort of like those motorbike traveling cases. If made right, many wuldnt eaven notice there is something different with the byke

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#11

I do not own a Honda Shadow and have honestly never checked one out. If it has two carbs then I would have to do some stupid stuff to make it one one air mixing valve but I would do it. My main problem with building this gasifier is the 7500 rpm thing. A normal four stroke for almost any other vehicle or tractor maxes at 3000-3600 rpm in my experience. With an engine burning that man cylinders of gas does it affect the needed dimensions of the internals of the gasifier that will be for that hp of engine? By “woodgas flame fronts” what do you mean? The speed which the gas burns in the cylinder? I will look up max gasman and see what I can find I guess, Thanks everyone

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#12

Ok, I have been sitting on this simple gasifier, designed and used by Joseph Monty.

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This was designed for a 8 hp engine but ended up used on a Ford which I think was 2000 cc. It would be a simple build and I think a proven design. You would have to come up with a cyclone and filter and on the Ford he did end up putting son a small cooler. I do not like burning pellets, but recently on Youtube there have been a few postings for making solid wood chunks/ pellets that I think would work great for this project. Hope you get something from the pictures TommC

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#13

The more I see other peoples gasifier dimensions, the more it seems that if you just build a gasifier undersized it will still work for a larger hp engine to a certain degree. If this was built with a 3" reduction zone it should be in theory built for a small engine, like 15 to 20hp. A 2000 cc engine should be around 100 hp or more if you use the general rule that 13cc to 17cc ~ 1hp. So since my engine is probably going to be somewhere around 70 hp and 750cc should I just build with a 3" - 4" reduction zone and hope it works? Doesn’t seem like a very good bet to me…

#14

hmmmm, built for a small engine yet runs a car just fine? The FEMA handbook recommends a much larger gasifier for 2000cc engine. Thanks for the pictures for proof, but now I am just confused.

#15

Hello Brenton and welcome to the DOW sir .

Where are you located ? Sure wish you could drop in on one of our gasifier events or if you are close to Alabama visit me.

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#16

You are right about that statement! It is a general rule (that l found only recently to be true) that its better to be undersized thain too big.
The main question still remains. What is your fuel size?

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#17

Wow, hey Wayne! I’m in Indiana, is there a place I can view the upcoming events on DOW? Maybe I can ride the bike down to AL when I get it done, haha.

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#18

As far as fuel size goes, I would like to run it on chipped up small sticks, that is what I have availible to me. I know it is very poor quality with low btu/ Lb but anything other than that is going to almost be a waste of energy to acquire. The fuel I am envisioning is about 1-2" in length and twig to 1/2" in diameter, and all mixed hardwoods with bark still on the ~10% water, dry sticks.

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#19

This looks like good fuel. Just be sure there isnt much small long twigs in there to give you bridgeing problems. I dont have much experiances with such small wood (exept pellets-terrible) perhaps others culd help you.
So lets say you have a 800ccm engine driven at 3000 rpm. On Maxs formula this gives you 0,8l x 3/1000rpm x 3 = 7,2l/s of max gasflow. Based on the fact you will use small fuel, the hearth will be wery small. For other info you have to wait for the chip kings to wake up :wink:
The min cooling surface on a nother Maxs formula is 1,7m2.

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#20

Hmmm, 7.2 L/s means very little to me, I think I might just be overthinking this. For a 750cc engine that runs 7500 max rpm, would having say… a hearth zone of 6" diameter x 5" height with 5 tuyers each .3" diameter at the top of the hearth zone, with a reduction zone 3.5" across, and a cylindrical biochar zone approx 4"-5" deep and 4" wide with the ash grate below, be working dimensions for this hypothetical engine?? I get lost in the equations. Also this may all be in vain because I am yet to even OWN a motorcycle. The purpose of this forum is to first figure out what qualities I am looking for in a bike, buy that bike, THEN critical dimensions of the reactor that correspond to that bike. Thanks for all the info