SuzukiSavage.com - Death wobble

mpescatori

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Re: Death wobble
Reply #30 - 11/07/16 at 05:31:35

Nigel-in-SoCal wrote on 11/03/16 at 22:35:57:

oldNslow wrote on 11/03/16 at 07:58:32:

Quote:

I don't know about Sportsters, but Dyna and Touring bikes all share the same design fault: the rear fork is hinged not on the frame but on the gearbox.
Huh]

Take a peek at a Ducati Panigale. Steering stem and swingarm are both bolted to the motor/gearbox. Is that a design fault too,?

http://newatlas.com/ducati-panigale-1199-naked-fairings-frame-pictures/22035/

There have been, and I think there still are, MotoGP bikes that are built similarly.

The execution is likely more important than the design itself.

True! I think the front end, swing arm and rear sub frame are solid mounted to the engine on the Ducati. But the HD power plant is rubber mounted to the frame, I believe. That must be less stable.

I think somebody saw wrong...

That big fat triangular thing is the fuel tank, designed to act as part of the frame.
NOWHERE does it say that the steering stem and swingarm are bolted to the engine.
I personally had a Ducati 450, the biggest single Ducati ever made [library pic]
As you can see from this picture, the downtube of the frame connects to the engine case... certainly NOT to the head!

Furthermore, Ducati twins have the front cylinder flat horizontal, and the rear downright vertical BUT at the rear of the engine.
So there is no way you can attach the steering stem to the vertical (rear) cylinder.
Also, the rear swingarm is bolted on the apex of the upside-down triangle under the seat - a design copied by Willie Davidson 30 years later when he came up with the FXR.

Roll Eyes

Actually, yes... the last time I testo rode a Panigale it did have a little bit of wobble... but then I was doing 205mph !!! Cheesy

http://youmedia.fanpage.it/video/ad/VAnePOSwHTKu10U1

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Ruttly Serious Thumper Offline Thumpers Rule Posts: 5107 Manteca , CA Gender:	Re: Death wobble Reply #31 - 11/07/16 at 06:40:29 Yes Harley rubber mounts their engines That video looks like that Harley came out of a Jello mold Would never own any bike that handles like that
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gizzo Serious Thumper Offline SuzukiCabbage. It's Savage. Posts: 1318 Australia	Re: Death wobble Reply #32 - 11/07/16 at 06:52:37 Belt drive ducatis have the swingarm pivot in the back of the crankcase. But a normal steering head arrangement. The paralever BMW's are an example of a motorbike with no frame: everything hangs off the engine. They handle pretty ok. Never ridden a panigale and probs never will. That must have been some kind of fun.
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oldNslow

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Re: Death wobble
Reply #33 - 11/07/16 at 07:01:01

Quote:

Gone is the traditional Ducati trellis frame that usually wraps around the engine. The Panigale is famously the first production bike to abandon an ordinary frame altogether. One chunky piece up front joins the main front end headstem bearing races to the top radiator and the front and rear cylinder heads.
A pair of boomerang-shaped supports hold the seat and tail unit up off the engine's rear cylinder, and a similar boomerang shaped mount hangs the swingarm off the crankcase. The rear shock sits slightly beyond horizontal, attached to the side of the rear cylinder. The engine doesn't sit in a frame; the engine more or less *is* the frame.

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mpescatori

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Re: Death wobble
Reply #34 - 11/07/16 at 10:35:05

gizzo wrote on 11/07/16 at 06:52:37:

Belt drive ducatis have the swingarm pivot in the back of the crankcase. But a normal steering head arrangement. The paralever BMW's are an example of a motorbike with no frame: everything hangs off the engine. They handle pretty ok. Never ridden a panigale and probs never will. That must have been some kind of fun.

I beg to differ.

Up until my accident on 7/17/'15 I had two Beemers, both with telelever front suspension.

I can assure you there was a frame, it's just not your average everyday tube frame.

But it handled like a million dollars. Never have I had such a wonderfully Handling bike !

Incidentally, my "Big Blue" scrapes the pegs on full throttle and a full load - 90mph on highway bends on a 800 lb. bike is no easy feat, but I can do it on the Beemer Cool

(again, library pic)

Really ! I believe she is the only fuill dresser on which you can scrape the pegs and NOT fall over !

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Maurizio Pescatori, Esq.
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Mikuni BST40, K&N filter, Stage2 cam, Verslagen tensioner, Sportster muff, 120 proof moonshine, Pirelli MT 66 tourers... and a chain conversion too !

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Ruttly Serious Thumper Offline Thumpers Rule Posts: 5107 Manteca , CA Gender:	Re: Death wobble Reply #35 - 11/07/16 at 19:18:59 Looks like "A frame suspension from a car
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Kris01

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Re: Death wobble
Reply #36 - 11/07/16 at 19:40:40

gizzo wrote on 11/04/16 at 15:57:16:

Norton did it with the commando. Engine/transmission/final drive were all rubber mounted together to isolate vibration from the frame. Difference is, Norton understood how to build a fine handling motorbike so they got it right.

They called it their Isolastics system. From what I understand, it was hard to adjust properly. But when it was dialed in, it was a well-oiled machine!

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