Triumphrat

Avatar · 06-25-2006

While leaned over in a turn I encountered a terrain change. The road went from one type of pavement to another. The seam was lower than the current surface I was cornering on. The bike felt like it was flexing. I'll try my best to describe it. Imagine two giant hands grasping the front and rear wheel. Now both hands are wringing the bike like a dish cloth....the x axis of each wheel was being skewed oposite of each other....

Is there some sort of suspension adjustment I can make to alievate this?

I've noticed this same behavior when the pavment seam is higher than the current surface as well.

JWoodsie · 06-25-2006

All bikes flex. Most of us arent good enough riders to be able to percieve it. I would be looking at swinging arm bearings, headset bearings, fork oil level and triple clamp security.
No suspension adjustments on a Legend I'm afraid. Check your tyre pressures as well.
Hope this helps.

jimmyj900 · 06-25-2006

Check your tires and pressure too.

Jim

Avatar · 06-25-2006

Thanks for the tip.

I have linked compression and damping adjustment on the rear monoshock ( hagon ). Anything I could do with that to help?

Rincewind · 06-26-2006

I have felt a sort of 'flexing' feeling when pushing it in some corners and I've been associating that with the old-school steel backbone frame. Correct me if I'm wrong, but that style frame is more susceptible to flexing than the newer aluminum perimeter frames popular on sportier bikes. Though the steel backbone itself is quite thick, it makes for a very thin overall structure for the bike without much left-right support.

I get some wallowing and bucking sometimes in corners, and that I associate with the suspension (or my poor riding), but the flexing I think is the result of the frame.

[ This message was edited by: Rincewind on 2006-06-26 05:27 ]

MickMaguire · 06-26-2006

I am not convinced the frame is at fault here. I know thew wallowing feelings you are talking about and I no longer get it with my suspension / wheel change. It was also greatly reduced if not elimated by the race tech upgrade I did to the stock forks (before I went to th eZRX items) and the swap to the TBS rear shock. I think its largely a problem of squishy damping coupled with soft springs.

The stock classics are not really "sports" bikes but more in the soft riding cruiser mould and as such they have cheap supensions. the exception to this is the TBS which is much improved over the other models (though still not Daytona performance).

[ This message was edited by: MickMaguire on 2006-06-26 06:48 ]

jimmyj900 · 06-26-2006

I pretty much agree with Mick here in that I don't think it's a frame rigidity problem. In the Classics the engine is a stressed element of the frame which makes it very rigid overall. The headstock bracing is also good as is the 'outrigger' arrangement on the rear of the frame.

JWoodsie is also quite right about checking the headstock adjustment and front suspension condition.

In addition to the tires I'd also look at the rear suspension and shoot some grease into the swingarm fittings.

Beyond the mechanical condition of the bike, I'd also point out that transitioning a change in road surface height is going to result in a momentary loss of traction and an equally momentary change in steering geometry as the contact point of the the tire is shifted by the change in road surface. That will produce a brief 'shake' in almost any bike that's different from a frame flex.

Frame flexing feels more like a wobble and is more protracted than the brief wiggle you'll get from a road surface change. That's based on personal experience with a CB-350 twin and a Kawi 750 Mach IV. The CB is pretty soft and I need to do some welding and bracing, but the Mach IV was like riding a snake through turns -- no where near as sure footed as the new Triumphs.

Jim

06-26-2006

I'm sure all the components on modern sports bikes help reduce this kind of flex (or at least limit it to non-problem orientations). But ours are not sport bikes. Personally, I prefer the clean look of my T'Bird to having some eiffel tower type structure along the side of my tank.

My T'bird is much better in this regard than my previous bikes (mostly '80s kawasakis with Norton style double front frame tubes, and rubber mounted engines) so I agree with Jim that the stressed-member design is basically pretty rigid, even if swapping out some suspension parts for better (more expensive) items might make a difference. On the Kawa's though, the particular tyre brand/model and pressure (particularly in the rear) made a big difference to this effect so its definitely worth looking at simple (not to mention cheap!) solutions, particularly if your tyres are getting worn. Even a couple of pounds pressure either way made a noticeable difference.

[ This message was edited by: davidoc on 2006-06-26 19:18 ]

Slinky · 06-27-2006

Avatar, I wonder if what you are experiencing is wallow.

I used to get some wallowing in bends at about 80mph or above, or even 100mph or so in a straight line. It could get pretty scary at times.

A change of tyres and heavier fork oil cured it, I don't seem to have any problems now.

I would have to agree with the others, the frame with engine as a stressed member is a very stiff arrangement, and the 43mm forks are pretty stiff too.

Rincewind · 06-27-2006

Alright, it appears my comments on the frame were way out in left field. After all, this is the same frame that the early Sprints, Speed Triples, and Daytona's used, right? At least that's what it looks like from my Hayne's manual. So, the frame is a pretty sturdy design.

:hammer: