Mounting the engine on heavy-duty rubber to reduce vibrations?
 

I used to work on a sailing boat for a while, and I rememeber the old diesel engine it had was rubber-mounted to dampen the vibrations when it was running (something that I know a few cars have too), and I was wondering if anyone has ever considered/done anything similar to their bike? Would it even be possible? I realize that it'd probably mean modifying quite a bit to make it all fit and such, although in the case of my motorbike (a Honda Dominator), most of the mounts (that I've been able to see) are not directly onto the frame, but rather the engine is bolted onto pieces that in turn are bolted onto the frame.

IF it would be possible (even remotely), any thoughts on what material I could use to do this? Anything I would have to watch out for or take into consideration??c?

If this idea of mine is simply insane, feel free to say so... personally I do have the feeling I might be missing a few screws... :wacko:

Nevertheless... if it worked it'd solve quite a few other lil' issues and problems, not to mention reduce at least some of the stress on the rest of the bike (lets face it, the big single isn't exactly "smooth")... not to mention my own rear end :tongue3:

Your mad.
you don't want the engine to move in the frame as the drive to your rear wheel doesn't have a lot of lateral play in it.
Honda built the frame to cope with any stress the engine will put on the frame.
the rear engine mount and the swinging arm mount use the same fixing and would make the job too difficult.
normally the option left is to rubber mount the operator ie rubber mount the handlebars and the footpegs you shouldn't need the seat rubber mounting as you have a thick piece of foam between you and the bike (unless your foam in the seat has collapsed).

Some Buells and Harleys do this, it might be a starting point if you're looking for more info. Some kind of tie-rods are in place to keep the movement vertical-only, so the wheels don't lose alignment.

How you'd add this to a bike that wasn't designed for it though, no idea.

Rubber mounts
 

An alternative method for calming vibration can be seen on the newest Ducati Multistrada. The bike's handlebars are rubber mounted. This provides some isolation from vibration for the rider while allowing the engine to be rigidly mounted in the frame.

Isolastic
 

Norton did this with the Norton Commando back in the late sixties .
The engine , gearbox and swingarm were rubber mounted and consequently independant of the frame so the rider would not feel any vibrations .
It works .
But the whole bike was designed with this in mind .
To retro fit this onto another bike would be very difficult .

Brainstorming...
 

:funmeterno: ah well... I'd probably just have ended up with a "garage" full of a bunch of non-functional bike pieces if I'd tried anyways... and me standing beside it all with a face something like :oops2:

hmmm... although perhaps... mount the "vertical" mounts (ie, where the screws are perpendicular to the ground) on rubber, and the horizontal ones... well, the rod thingy idea seems interesting... time to have another good look at how the engine is mounted to the frame...

Otherwise, perhaps... hmm... maybe if I can find my old book on materials science... see if there's something that could work. I knew I should've paid more attention in class... :sleeping:

Buggrit... I need to find a way to measure the various stresses on each mounting point. Or at least manage to make a rough guesstimate.

... ... ... ... ... ...

Somehow, I'm starting to get the feeling that 1. I'm using a bazooka to kill an ant and 2. I'm just gonna end up with a half-arsed system that will do nothing but screw everything up and break down all the time at best.

Perhaps I should try a gel pad and rubber mounting the handlebars first... and as far as luggage goes, rubber-mounting a rack should be much simpler than doing the same to the engine, although probably a lot less effective.

Anyone have any ideas for a more-or-less permanent solution to insulate luggage/equipment from vibrations? I mean aside from foam/gel wrapping it (which is, at best, temporary and would use up more space than I'm willing to sacrifice). Whacky/weird ideas welcome too :clap:

The Domi most probably uses its engine as something we engineers refer to as a stressed member. Lots of bikes do. Lots of other bikes don't and use either rigid or flexible engine mounts.

Rubber mounting a stressed member of the frame will sooner or later leave you with a cracked frame and perhaps with a couple of cracked bones too.

The reason why the boat's diesel was rubber mounted is it's got a crude chunk of cast iron as crankshaft web, is as heavy as the boat's anchor and lacks sophisticated features like balancer shafts which are abundant in your Domi engine.
The diesel would have vibrated the boat to the bottom of the ocean in no time would it not have been for the rubber mounts. Especially if you are talking fibreglass or wood for the "frame" with relatively thin and large sheets of aluminium or steel only being marginally better. Not to talk about ferrocement which is said to crumble all by itself ;)

If you think your Domi vibrates too much go and get a Fireblade or R1

Exactly.. nearly all engines are stressed members on bikes now.. Deffo on alloy twin spar and alloy tressil frames.. A steel "cradle" frame would probably be ok as the engine is just hanging on the frame but I still wouldnt mess with it..

As people have suggested, Rubber mounting your bars and pegs would do more and getting a gel seat too.... :thumbup1:

You've been given the solution already.