When you say the burn area do you mean the size of the nozzle nozzle pipe ? is so then 1 or 1 and a half inch would be fine for a flute type nozzle ’ what size is your container going to be on the bike ? do u have any pics of the component’s your going to use ?
Dave
I’m actually referring to the combustion area, I’m wanting to put it on the bottom of the tank, so that I can just feed charcoal through the fill point on the tank. I haven’t actually started on it yet, but I’m wanting to figure out what dimensions I have to utilize for it to work. And I’m wanting to use the gasifiers intake air as the first cooling point.
Sorry mate not sure i can follow that idea , ( i’m bloody old ) the way your explaining it sounds like your expecting to feed charcoal into the system as its running dropping fuel in the top allowing it to flow to the bottom where the air intake cools the gas . lol please if you have a drawing or a sketch of what you mean or maybe wait till the over side of the world is awake there is a lot of smarter people over there .
Dave
Lmao, sorry! I wish I knew how to explain it better, but It’s 1 in the morning here, so brain ain’t working right. I’ll try to make a drawing tomorrow to better illustrate what I’m saying 
What i can say is this i have seen a few motorcycle gasifier builds from old black and white movie reals that look like they have ammo boxes on either side of the rear wheel 1 being the gasifier the other the filter box , so they look like a set of saddle bags , one was even from here in Victoria AU .if u have not seen that video i can try find it for you .
Dave
You could do it with a unit like Bryan Whites. New charcoal gasifier build. You would have to insulate the reaction area with ceramic fiber blanket with a sheet metal skin over it. You could also look up Goran’s mini-bike build. I don’t think you are going to get much distance out of a small unit on a high reving engine like that no matter what you do but with an updraft charcoal unit you should not need extensive cooling plumbing. It will be interesting to see what you come up with.
The more you preheat the more exhaust gas or water drip you can use.
The carbon and water in engine exhaust gas is free potential fuel, why not use it I say. Both EGR or water drip also stop the nozzle from eroding by cooling it down.
The best preheating for a charcoal gasifier is with a basic form of the ‘‘Kalle’’ (Källe) style with an intake nozzle going from the top of a hopper to the bottom and produced gas traveling back to the top. This way countercurrent heat exchange is achieved with nothing but just a length of pipe.
The Kalle style is very hard to replicate with store bought materials.
Also exhaust gas can work to keep nozzle temps low, but it doesn’t add the power that atomized water or steam can add.
The advantage I find with the flute style updraft is water drip has time to vaporize and the steam can rise into the glowing charcoal. Sort of self metering based on how hot the flute gets, water won’t prematurely be added to the reaction. The only other simple way to ensure the water is added as a fine mist is to replicate what Matt Ryder has done with his nozzles.
No need to make the complex Kalle style, as in no need for the automatic ash cleaning and such. I think Gary Gilmore has made a simplified one with his own name on it.
As for the water drip, pressure is what determines if water is pulled in.
In a top to bottom nozzle the water would have plenty of time to vaporize from contacting the hot walls before it touches any of the charcoal.
The reason to use exhaust gas is that it’s very simple to set up and does not need refilling. Don’t get me wrong, water will always make a more potent product gas by displacing nitrogen and that’s just a fact. Hence I said on purpose that either will work for taking advantage of preheating surplus heat.
Yes, if you use heat to expand the intake air this is less nitrogen. This will make more powerful gas while increasing velocity. Is this worth the added complexity. For me, no. If it works it works, you can spend time using your gasifier or spend a lifetime improving it to death.
The Kawasaki has a 3.7 gallon fuel tank, which I’m wanting to add the gasifier to the bottom of it, kind of like this.
I think I could also add another 2-3 gallons to its capacity if I can remove the carburetor.
That’s way too small.
You’d be best mounting it where paniers would go in the back.
You could turn the gasoline tank into a water drip tank if you’re wanting to go 100% Charcoal.
Is the capacity too small, or the gasifier? Cause I think I could double the gasifiers size without too much issue. I’m mostly trying to keep it hot with the charcoal, and use water for most of the fuel. It gets 78mpg right now, so what do you think it’ll get on a cubic foot of charcoal?
For a 250cc engine you’re best off with a gasifier that has at least a 9" circular footprint. You also require a particulate filter. You need the fuel to act as the insulation for the gasifier to prevent burning you. The way you’ve drawn it up you’d melt your coinpurse and jewels.
If you mount the gasifier in the rear, where a saddlebag would go on one side, you could balance the bike back out with your filter on the opposite side.
The only other way you could mount the gasifier is in a sidecar.
I’ll draw something up in a minute to flesh out the idea.
Here’s a video showing a bike that’s at least a 350cc and more likely a 500cc.
This is probably a Pederick hot plate updraft gasifier.
Also I would get a bigger sprocket to go on the rear wheel. Play around with your gear ratios.
I see! I should also mention that I’m trying to make it a downdraft, so it takes the heat away from the hooper, unless it starts running low of course! You can’t really see it in the last photo, but I have over a cubic foot of additional space in there, if I can replace the carburetor
I’m wanting to use this for doing doordash, so I need to have a 140+ range is all, if possible!
That would be a challenge.
Even with my 55 gallon hopper on my Mazda’s charcoal gasifier I would be lucky to get 60 miles on a refill, and that’s almost 100lbs of charcoal when full.
Updrafts don’t require much gas cooling, if you use metal lines for the routing it will be plenty cool. When the gas begins to get hot you’ll know to refill.
The fuel efficiency of the engine certainly plays a factor, but you only get so much distance per pound.
For a small engine like that 250 I honestly think to save weight an updraft would be best.
In terms of raw wood, Auburn University found that 16lbs is equal to 1 Gallon of gasoline. I suspect Charcoal would be equal to that or I would use that as my rule of thumb provided you used good hardwood charcoal.
Volumetrically it would take more space to make up that 16lbs than raw wood.
Downdraft charcoal gasifiers are a tricky business. They require durable nozzles to not melt away. With an updraft built like Koen’s central bottom entrance or Kristijan’s Flute style the heat will be away from the nozzle than a side entrance Simple-Fire.
Another benefit that an updraft will have for a motorcycle is you have virtually an infinite Turn-Down Ratio, i.e. a minimum and maximum RPM that the gasifier could feed. Those Kawasaki engines love their high RPM.
OK i now see why we were on totally diff idea’s if it was me forget using the gas tank for charcoal or water , leave the tank for petrol and leave the carbs in place , then go look at Matt Ryders Ammo can gasifier . this would be the best way to go if you want a downdraft and a range and if its short on range just hop off and top up the gasifier in seconds , as Cody says you don’t want to risk yer crown jewels for a few miles of free motoring or anything else come to think of it .
Dave
Do those bikes have an electric starter? I wouldn’t want to have to start up on wood gas with a kick starter. You will also need a battery operated suction blower like Tone uses on his tractor, to get workable gas until the engine can take over. You may be able to get a 140 mile range if you had the gasifier beneath about a six foot tall, one foot diameter hopper strapped to an 60’s style sissy bar. Even that would probably not be enough.
While I did suggest using the fuel tank as a water tank, I know how delicate the one way bearings on these Kawasaki engines can be. I had to replace them twice on my Vulcan 500. Not fun.
Starting on gasoline would be easiest and then switch over to charcoal. Then you could use the engine as a way to prime the gasifier, on an updraft charcoal system this isn’t an issue. I never used a blower for the updraft on my Mazda.
If I crunched some numbers and used propane tank bodies for the gasifier, a reasonably tall system you might get away with 15 gallons or 3 20lb tanks welded together. Or use an old air compressor tank around the same diameter.
Assuming you start to get hot gas after it goes half empty with an average 6lbs per 5 gallons density of fuel(my average), that’s 18lbs of charcoal filled to the brim, 9lbs per refill if it goes half empty.
With my Mazda that would take me 18 miles. Let’s assume you manage double that economy with the Ninja 250, that’s 36 miles of combined economy driving in a town. My Mazda got 2~ miles city driving per pound of charcoal.
With 4x that efficiency you’re looking at 36 miles before needing to put another 7.5 gallons or 9lbs of charcoal back in.
I ran a mixture of wood species in my charcoal, you might be able to get a better density if you only use dense hardwood for the charcoal stock. But then it’s only percentages of gain that I personally consider diminishing returns in the search for wood to burn. If you can source a lot of hardwood then it would be worth it.
To put into perspective how tall 15 gallons at a 12" diameter tank would be you’re looking at something about 3 feet tall minimum. 20lb tanks are 1ft by ft.
The rectangular ammo cans are a good candidate, and you could extend the hopper horizontally so as you lean in the turns it will jostle some fuel into the hopper, but I want to say the most reasonable sized ammo cans I’ve found only hold about 10 gallons, I’d have to measure the ones I’ve bought to figure that out.
A downdraft charcoal gasifier won’t get you better mileage, only the insurance of accidentally adding bad charcoal to the mix and not making tar. They’re heavier on average and the nozzles burn away very quickly if you don’t use a material like silicon carbide. All the space used up for one takes away from hopper capacity as well. With a car or truck it’s worth the weight and size difference but on a motorcycle I personally think an updraft is ideal for the weight. That’s just my opinion though it isn’t backed up with any particular empirical evidence.
Edit: to put things into perspective here’s one of those ammo cans. It’s 32" tall and just barely over 9 gallons in capacity.
