Café Commando build thread
- Thread starter Jeandr
- Start date
slimslowslider said:
The interesting bit in that Buell's patent describes four links - the three link solution is presented as a bare minimum. Three is kinematically incomplete as I said before - it means that engine vibes are transfered into a screw-in motion of the drivetrain against the frame and put an additional and undefined load on the remaining rubber link which is the shock absorbers (which sort of spoil the party on a Commando anyway). Eventually to do it right it would be four links and feeding the rear suspension loads into the cradle.
Tim
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I to want to see it together or at least with both the front and rear wheel on.
Tintin said:
Maybe three links are better than the ISOs with their built in looseness, at any rate, it is something I wanted to try. It is worthy to note that the new Nortons are solidly mounted, the vibrations being taken care of with an ofset crank and a balancer. Harleys on the other hand really shake their booties, but are not known for razor sharp handling.
Jean
Made my top link...
I will change the plate bolted to the head to steel instead of aluminum, this will give a bit more room and prevent any contact to the gas tank. Before adding that third link, I could move the engine/transmission with ease sideways, after the third link, rock solid. With a pry bar, I could move the engine/transmission up, down, front and back. This is looking good.
I can see how a good head steady can improve a stock Norton, the stock little rubber bumpers can move every which way, that can't be good for handling.
Jean
I will change the plate bolted to the head to steel instead of aluminum, this will give a bit more room and prevent any contact to the gas tank. Before adding that third link, I could move the engine/transmission with ease sideways, after the third link, rock solid. With a pry bar, I could move the engine/transmission up, down, front and back. This is looking good.
I can see how a good head steady can improve a stock Norton, the stock little rubber bumpers can move every which way, that can't be good for handling.
Jean
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That sure doesn't look like much clearance. Might just be the photos.
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Here is a question from a non-engineering type guy (Dammit, Jim, Im a DOCtor, not an engineer): since the engine is now rock-solid and basically integral with the frame, I can see the likely handling benefits, I can imagine that the entire bike might shake more at idle (or will it?), and I can imagine that the frame/links/mounting hard points might have some risk of fatigue. Here's my question, and sorry if it's dumb or naive: how does this affect the engine internals? If you take away the stress-dissipating connections thru the rubber isolastics to the frame, are you taking away the engine's opportunity to, well "relieve" itself of those stresses through vibration? Does this add any stresses to the engine internals, or is it built to take that stress anyway? Just curious, cause you all know a heckuva lot more about this stuff than I do. But man, it's fun learning this stuff here. And Jean, your engineering is pretty slick, I keep getting more impressed with each new addition. Good luck!
P.S. let the "Norton relieving itself" jokes begin...
P.S. let the "Norton relieving itself" jokes begin...
Look more closely. It's attached to the frame on one end of the rod, to the motor on the other. This gives full motion forward
and back, but Zero side to side. So it allows the motor to vibrate as it will on the isolastics. But keeps it perfectly centerlined.
and back, but Zero side to side. So it allows the motor to vibrate as it will on the isolastics. But keeps it perfectly centerlined.
askdoctorday said:
Rock solid from side to side, I still have the rubber "biscuits" allowing the motor-transmission-cradle to shake in a vertical plane. I guess there is always a risk when something from a factory is modified, but then again if you look at the first frames that Norton made for the Commando, dubbed "the widowmaker" you find out that they don't always bat 1000, many times at our expense.
And Swoosh, the picture doesn't show the full clearance, but after making another piece bolted to the head there will be more clearance.
Jean
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Ah, that makes sense that the engine/cradle can still move. So it's not about eliminating movement, it's about controlling and redirecting the movement in a predictable way rather than the "Dutch Roll" that the stock mounts allow. Very cool, gentlemen- see, I learned another new thing. Now I know my next modification. Thanks!
Jeandr said:
Technically speaking no as the Isos do not introduce this screw-in motion which only the fourth link would take away but that is probably a bit academic. However the Isos if they are allowed (and consequently made) to work in the intended way are a really sensible idea and there is no reason not to use them IMHO. Rod link solutions always need a certain degree of flexibility in order to replace these but the relatively soft Commando frame (especially the lower rails) allow for that - but they are certainly not the answer to all Isolastic prayers.
Fair enough. :wink:
Tim
Made a steel top link to give me more clearance between the bottom of the tank and the fixing screw
Sorry for the bad picture, now I have good 5mm of clearance. I tried to pry the engine up and I could not get it to touch the bottom of the tank
I had time to weld in a plate to cover the ampmeter and switch holes in the headlight shell, I will fill it with Bondo and paint it.
Jean
Sorry for the bad picture, now I have good 5mm of clearance. I tried to pry the engine up and I could not get it to touch the bottom of the tank
I had time to weld in a plate to cover the ampmeter and switch holes in the headlight shell, I will fill it with Bondo and paint it.
Jean
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Small progress, teasing everyone, making us want more with nice pictures showing just enough of the project to entice those who read the thread to keep coming back for more.
britbike220 said:
Looks like little steps, but its not like picking stuff from a catalogue, I cut the flat parts from stock, shape them, make sure they line up, turn the round stuff to the right dimension, weld the two together. Just plugging up the headlight shell took a while to form the metal to fit inside, then carefully weld it in. I also fixed up my swing arm (not shown) to plug up the hole in the tubing. Then there is the pondering time when I just sit and look at what I have done to be sure I did it right and if not then think about what to do next to fix it. To top it all, I had to clean the garage, working steel is really messy.
Jean
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It's great stuff to help stave off the winter madness Jean 
britbike220 said:It's great stuff to help stave off the winter madness Jean
That is why I do it, keeps me sane. While the project seems to go in very different directions, it is like a movie shoot where they record scenes out of order then the director asembles the whole movie in order so the story makes sense. Some of the things I do are in order, but some are not at the end of the day, the whole thing will come together and (I hope) it will look good to me and to others too. My goal is to bring it to the Norton rallye next summer.
Jean
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