The MagBike

[Rhynri]

I decided to move this discussion to its proper location, instead of my introductory thread. After speaking with Curtis in Texas, we are looking at the FJ1200 as a possible source bike. It has a modular frame built to support a rather massive air-cooled engine, with lots of room on every side. In addition to this, the bikes are known to last north of 200k miles so you do not have worries about the longevity of the parts. It has a high curb weight, and is designed to carry that weight well. The concern now is to find if the 1.6l or 1.9l VW engines will fit in the space vacated by the stock 1200cc Inline four. If anyone would happen to have dimensions on either of theses engines as well as weight, that would be appreciated.

Here are some pics of an FJ1200 stripped down to the frame and engine from this site. It is a chain drive bike.

• Wide Shot
  Closeup
  Frame Empty

Some of gallery pictures are interesting from a mechanical standpoint for anyone curious about engine construction.

[Rhynri]

Wow. Just Wow.

So I was looking around ebay to see what major parts for the FJ1200 go for nowadays. They were often parted out for the engines (for mini stock car racing) and frames seem to run about 350$... except for this one. I was looking at the listing thinking about how that frame looked a little beat up for a bike "in great condition for it's age" with "no evidence of a crash" when I scrolled to the bottom and saw a picture of the whole bike.



That is my old FJ1200 in that photo.

After picking my jaw up off the ground I start to get angry. THERE IS A BULLET HOLE IN THE FRAME for Pete's sake (fourth picture down you can see it on the far side above the the join between the top rail and the first member traveling down in the front of the bike). How can they list the parts as "Never crashed" when I WAS IN THE CRASH THAT TOTALED IT. Or rather, a victim of the crash. There is a reason they have to take a picture from that side of the bike. The other side is missing some parts, never mind the anti-dive unit that fractured off the fork or the destroyed side of the cowling. So I did what any reasonable person would do and wrote a very polite letter through my teeth asking for a list of other parts from that machine because I am working on a project FJ1200. And then I will report every single one of them and deep six this guy straight off of the face of the internet.

Grr....

[coachgeo]

What is the dimensions of that 4cyl compared to the VW 1.9 and 1.6?

And glad you survived the bullet holed bike tumble!!!

[Rhynri]

That is what I am trying to find out. I kind of eyed out the build Mouse did, and did PM him concerning the dimensions (at least I think I remember to mention the dimensions!), as well as ask a few EBay'ers if they had the dimensions of the engines they are selling (hah, good luck), so once I find that out I'll have a better idea of how to proceed. The stock engine in that bike is huge (you'll note it goes clear to the upper frame members) so I have my fingers crossed. We shall see though.

[pietenpol2002]

I think it's safe to assume you're not going to shoehorn the V-dub into that FJ frame - even with a liberal dose of vaseline. The 1.6/1.9 is no small engine by bike standards. Stephan Sanderse's 1.6 is a favorite of mine. Viewed below if you haven't seen them before.

http://1.bp.blogspot.com/-jEBa3C-nU_4/T ... igzark.jpg
http://2.bp.blogspot.com/-a7D3CDDua3c/T ... toduda.jpg
http://3.bp.blogspot.com/-4A0UNg3VdYU/T ... toduda.jpg
http://2.bp.blogspot.com/-a7D3CDDua3c/T ... toduda.jpg
http://2.bp.blogspot.com/-0tXKXiNqniw/T ... toduda.jpg
http://4.bp.blogspot.com/-8fcB3H1SlNs/T ... igzark.jpg
http://3.bp.blogspot.com/-b0LXa4TpZwg/T ... igzark.jpg

And then his earlier rendition, which looks nearly identical to his first.
http://farm2.static.flickr.com/1350/134 ... c008_o.jpg
http://www.youtube.com/watch?v=XFyPyA5vVSc

As much as I love the VW, I'm with Coachgeo on this one - go with a 3 cylinder. The Daihatsu/Briggs is not real plentiful here in the states and typically comes at a rather dear price. Don't rule out the range of lowly Kubota's. Numerous current production 3 cylinders from which to choose with parts available just down the street at your local Kubota dealer.

Here's an example of the kind of used engines that can be found on Craigslist (although I might be inclined to go with the 905/1005 or 1105 for more power.
http://wyoming.craigslist.org/pts/3054467927.html (edit: link no longer available)

You might even find an example that would fit the FJ frame. They're pretty small. For example the 722 is 17" long, 16" wide and 22" tall. And those are the manufacturers dimensions which can often be reduced with a bit of repositioning. The one thing the FJ frame can tolerate is heigth.

You'll find numerous examples of Kubota fired bikes here on Dieselbike.

My $.02

[Rhynri]

The stock FJ1200 is 90 inches long, has 5 inches of ground clearance, and the same bore as a 1.6L, the stroke is a good part of an inch shorter, true, but like you said, it tolerates height. The FJ's motor is entirely air cooled with some rather large fins, and the entire config winds up being quite large, most of the 600+lb weight of the bike is engine, the other components are pretty light. The A and B lower frame members remove, and the rest is pretty modular. I just need to know the dimensions of the 1.6l and 1.9l before I can go say it's not possible. As I have described, an engine pushing 25hp won't cut the sauce where I live, especially when it's making less torque than the original powerplant. That is a beautiful build though, and thank you for your input! I'll go to the kubotas and such if I absolutely have to, and then it will likely be inside some sort of very light tall dirtbike-frame. If the FJ won't work, I'll just find a bike that will.

EDIT: some other information - the FJ is 30" wide (fairings in front) so much so that the fairings get integral sliders on them because they hit before the handlebars do. As the second picture on this page shows, height is not an issue if you are willing to modify the stock tank. All we need to know is width, either side to side or front to back if you can mount it sideways.

[dethmachinefab]

I would build a 3 cyl, and you can keep the bike weight near 600lbs somewhat easily. Driveline set up seems much more easy. A 1000cc engine can make very good power with some boost and fuel. 50hp is no big deal with most of them. My caterpillar powered bike 3cyl will go 120mph (runs out of gear) without issue, and get there fast. I put together a driveline for a customer with a small d722, more fuel, rpm, and made 15psi manifold pressure. When that turbo spooled the bike accelerated quite good. I can not wait to finish my 100hp 3cyl build.

[Rhynri]

Which engine did you use for the build? Also, what did you wind up getting for fuel mileage from the bike? I'm curious to know details of that build, if you could help, I would love to hear them. You could post or PM them if you wish.

[Rhynri]

Found out today from a helpful ebayer that the FJ1200's engine is approximately 220lbs (dry) so anything in that neighborhood the bike is already tuned for.

[dethmachinefab]

I have done builds with:

-yanmar 395 (958cc i think.)

-cat c1.1 aka perkins 403 (1113cc)

-kubota d722 (719cc)

current build - kubota d1005

next build- deutz 3cyl, Neat little engine. Overhead cam with unit injectors.

[Rhynri]

I love deutz, so I am interested in which one you are using. I know they have some small yet powerful 3 and 4 cyl engines GEHL uses in their skidloaders. I have also looked at the Kubota 1105 turbo, which seems like a good option, if a bit pricey. What would you recommend?

[dethmachinefab]

The deutz is a f3m1008

[pietenpol2002]

Indeed, the Deutz has the power. But, outriggers required.

[zarquon]

The deutz is a f3m1008

And thats a rebranded Lombardini LDW903.
If I'm right this one is in Daves Tiger, too.

[dethmachinefab]

The deutz is a f3m1008

And thats a rebranded Lombardini LDW903.
If I'm right this one is in Daves Tiger, too.

Yes, thats it. I have not had time to look into it, but it should be able to make good power if the fueling is there. Don't worry, i will post a build thread.

[Rhynri]

The smart engine really seems to be the engine of choice if you can manage to find one. shame they don't sell them in th US. Like i said, we really need a purpose built bike diesel.

[Rhynri]

I found some more information on a possible engine to look into, the 1.6L turbo VW. The man I contacted at GEX gave the dimension of their GX 10853TH rebuilt VW motor as 23" high x 18" long x 13" wide which should fit although it may require modifying the fuel tank, which is acceptable. The biggest issue is drivetrain. The irony is that the stock drivetrain would work just fine if it wasn't built into the engine. Things are looking up, though everything will have to wait until the Army figures out what they are doing with me. I know now I am being medically retired for certain, at least.