Cafe Racer Forum banner

1 - 5 of 5 Posts

·
Registered
Joined
·
1 Posts
Discussion Starter #1
Hey everybody! I'm new to this forum, but no stranger to motorcycles! I have always had a passion for bikes, up until 2 years ago when I high sided my Ducati 748 and slid back first into a metal sign pole, paralyzing myself permanently from the waist down. Bummer! I was restoring early 70's Honda's in my free time then, mostly cl350 scramblers. I wound up with a few extra parts. I'm looking at building a cafe racer that I've had in my mind for the last half dozen years or so with them. It's about time to start buying the parts I need, so I thought I would sign up here and get some advice, so I don't wind up doing things twice! Hopefully you guys have some good information for me.

The overall look I'm going for is basically a cafe racer crossed with a MotoGP bike. I'm looking at putting a superbike front end on it (forks, hub, triple tree, clip ons, brakes), custom glassing a tank that has a motogp feel to it, but minimal like a cafe. I want to swap to a rear mono shock, like a motogp (I already have a Showa from the Duc). I'm going to have some fairings, but very very minimal, so I don't lose the cafe spirit. And overall, just have the bare minimum on the bike as possible, with everything hidden that I can hide. Get the idea? Great!!! Now on to my questions!

The engine I'm using is the 748 Twin out of the Ducati I crashed. My biggest concern is finding the right frame for it. I have a 1972 honda cl350 frame, but I'm worried that the Duc motor will be too much for it. I was thinking maybe a mid to late 70's Honda cb750 frame and swingarm? I'm no stranger to welding, and although my TIG days are over, I have access to a very nice MIG machine that will definately get the job done. So reinforcing a frame to handle the 748 motor is definately something I can do. I just need to know what frame I should look at that can handle the motor, as well as make the front end swap as easy as possible, as well as the rear mono shock conversion!

What forks should I look at swapping onto the frame that you just suggested? I'm looking for lightweight, and inverted. GSXR 750? Something from a liter bike? R1, zx10r, cbr1000 etc?

The rear mono shock conversion! Should I keep the swingarm that went with the frame or is there a swingarm that makes this easier? Or maybe pluck one from a 600cc superbike? Not really sure what to do here. The more I read about rear shocks, the more I realize this needs to be done very precise, as any slop or play in the suspension can lead to big trouble, as well as the correct geometry to ensure a decent level of performance. I suscribe to the "you gotta go fast before you can look good" mantra, so this baby needs to be mean on the track, just not for show!

I'm thinking of building a one-of-a-kind complete carbon fiber exhaust. I'm talking about a metal-less exhaust here, something I've never seen before. My real job is custom composite repair on aircraft at the local airport in town, so I'm kind of a pro working with the carbon fiber. I've thought about this extensively, and want to use this build to test my idea out. I'll basically be buying some wax that's used for this type of thing, in the diameter that matches the current diameter of the exhaust on the bike now. Then I will use a heat gun to warm the wax up to bend it in the appropriate places (after the rest of the build is completed, of course) and route the exhaust using this method. I'm thinking under the seat, coming out of the subframe fairing I make. Once the wax is shaped and bent to my satisfaction, I will then wrap it with prepeg (the resin infused in the carbon fiber) carbon, much like you would wrap the exhaust with heat wrap. once that is done, I will bake it to melt the wax, and harden the resin in the fabric. Once it's hardened, I will tape the outside to protect the look of the carbon, then I will take it to have it dipped several times into a tank of liquid ceramic. This stuff is so nasty the tank its in must be stirred every 10-15 min or else the entire thing hardens. It's on a special circut that if the power cuts out, it gets back up power from a bank of batteries, then a generator. Its the same stuff they use on the tiles on the bottom of the Space Shuttle. So that should be it, you have a pair of carbon tubes, that are bent to match how the exhaust needs to be run, with a serious coating of ceramic on the insides to protect the carbon and the resin from the severe heat of the exhaust. Super lightweight and just plain baddassery.

The rims are the last thing I need to think of. I wouldn't mind running basically two fronts from a literbike, or even have the front rim skinnier by an inch or whatever. I want to make the cafe/motogp blend harmonious. I don't want it to be unbalanced, where it just seems like a stripped down track bike, or a cafe with superbike forks. I want the thing to have SOUL, man. Like, serious soul. Something every motorcycle guy would look at and nod in appreciation, whatever their particular taste in bikes is.

So, I'll be documenting the build on here, updating periodically as I get things accomplished. I'll be taking a lot of pictures, drink a lot of beer, spend too much money, swear a lot of cuss words.... you know, a typical build haha. I'm looking forward to this build, what will most likely be my last, as being around motorcycles is just really bittersweet for me, and I'm going to have to move on after this last one. But with your help, I'm hoping to make this one special, something that will turn heads and be talked about at shows and bike nights. Something I can really be proud of.

Thanks in advance!
Eric
 

·
Registered
Joined
·
2,936 Posts
Sorry to hear about the accident but I think a 750 Ducati motor into a 350 frame would be a disaster. I'd be looking at something more modern and lighter and stiffer. What about a BMW K series frame as a sort of bevel 750SS clone? Might be easier to find than a bevelk frame and probably cheaper, but that's just speculation on my part.

For a MotoGP meets Cafe Racer look maybe look at say an FZR1000 frame. It's not exactly state of the art but it is reasonably long and rigid and not too fat in the middle. I have one buried in our outside storage so it's not accessible - otherwise I'd drag it out and take any measurements you might need. There have to be other slim options but few that could handle the torque of that motor. What about another modern Duc chassis with a blown motor? Is that a possibility?

I'm guessing that a suitable NCR frame is out of the question.
 

·
Registered
Joined
·
6,583 Posts
Maybe a TL1000s or (1st gen) SV650 frame? Monoshock ready and alloy - but still with a nod to a trellis design. I'm with Teazer on the 350 frame being a bad choice.

For the front end you may as well go for the latest USD radial caliper model you can get your hands on. There's very little difference between 600 / 750 /1000 fronts from a spring rate perspective. Most of the new hyper sportsbikes weigh within a few kilos of each other regardless of their brand or cc.

Sorry to hear about your accident but great to see you are still enthused about building.
 

·
Registered
Joined
·
23,286 Posts
can you weld? There was a company that used to sell 900ss replica kits for rubber band motors. It used their own frame design. Here is what I suggest, use the 748 stock frame and modify it to accept bevel Ducati mike hailwood replica bodywork. That is the best of both worlds.

Ducati engines belong in ducati frames. You are not smarter than a ducati engineer.
 

·
Registered
Joined
·
1,859 Posts
Baines Racing used to make a 900ss kit for later models.
twowheelclassics.co.uk sell some very nice looking frames and body work.
I'll repeat what Teazer and Hillsy said sorry to hear about your accident.
 

Attachments

1 - 5 of 5 Posts
Top