Heavy Vibration Issue

concours · Oct 12, 2023

My clutch hub center is all used up.
Not the splines, but the shoulder that accepts the bearing. BIG wobble.

Dellis · Oct 12, 2023

concours said:
My clutch hub center is all used up.
Not the splines, but the shoulder that accepts the bearing. BIG wobble. View attachment 110298 View attachment 110299 View attachment 110300

I did have a look at mine and it’s fine as it should be as I replaced it about 2,000 miles ago due to notching.

Dave

Torontonian · Oct 12, 2023

Dellis said:
I did have a look at mine and it’s fine as it should be as I replaced it about 2,000 miles ago due to notching.

Dave

Another guess is dry and tight rear isos .

KiwiShane · Oct 12, 2023

Check engine cradle fasteners

Onder · Oct 12, 2023

Check that the cradle isnt cracked...

Dellis · Oct 13, 2023

KiwiShane said:
Check engine cradle fasteners

Already checked.

Dave

Dellis · Oct 13, 2023

Onder said:
Check that the cradle isnt cracked...

Not thought of that so I’ll have a look.

Dave

Dellis · Oct 13, 2023

Torontonian said:
Another guess is dry and tight rear isos .

I’ll have a look but it’s not that sort of vibration, more like the feeling you get if you have a tight spot on a chain if you follow what I mean.

Dave

baz · Oct 13, 2023

Onder said:
Check that the cradle isnt cracked...

Are they known to crack?

cash · Oct 13, 2023

Dellis said:
I’ll have a look but it’s not that sort of vibration, more like the feeling you get if you have a tight spot on a chain if you follow what I mean.

Dave

If the problem is with the rear chain the vibrations will follow road speed, if its the gearbox/primary drive the vibes will follow engine revs, I would have thought.

Dellis · Oct 13, 2023

cash said:
If the problem is with the rear chain the vibrations will follow road speed, if its the gearbox/primary drive the vibes will follow engine revs, I would have thought.

Sorry I was trying to describe the type of vibration as in how it felt rather than the frequency.

Dave

lcrken · Oct 13, 2023

baz said:
Are they known to crack?

It's not uncommon for them to break at the thin area just above the right side lower engine mount bolt, particularly on race bikes. The usual cure is to weld it and add a reinforcing piece of some sort. In this picture of my cradle "collection" you can see three cradles that broke there and were reinforced by their owners. I've only had one break there, but I repaired it and it is still good after many years of racing. I don't know if they also break in other areas, but I haven't seen it happen.

Ken

baz · Oct 14, 2023

lcrken said:
It's not uncommon for them to break at the thin area just above the right side lower engine mount bolt, particularly on race bikes. The usual cure is to weld it and add a reinforcing piece of some sort. In this picture of my cradle "collection" you can see three cradles that broke there and were reinforced by their owners. I've only had one break there, but I repaired it and it is still good after many years of racing. I don't know if they also break in other areas, but I haven't seen it happen.

View attachment 110316

Ken

Wow
Thanks for sharing

Fast Eddie · Oct 14, 2023

lcrken said:
It's not uncommon for them to break at the thin area just above the right side lower engine mount bolt, particularly on race bikes. The usual cure is to weld it and add a reinforcing piece of some sort. In this picture of my cradle "collection" you can see three cradles that broke there and were reinforced by their owners. I've only had one break there, but I repaired it and it is still good after many years of racing. I don't know if they also break in other areas, but I haven't seen it happen.

View attachment 110316

Ken

You’re quite the collector Ken !

Very interesting picture, personally I don’t quite see how those strengthening mods actually strengthen the weak point ?

My hypothesis is that the cradles only break when another factor is added, ie loose engine to cradle fasteners.

concours · Oct 14, 2023

Dellis said:
Sorry I was trying to describe the type of vibration as in how it felt rather than the frequency.

Dave

cash is right, probing for more detailed description.

" I was getting a really heavy vibration through the foot pegs this was present in all gears"

Primary cover hitting the frame would be very low frequency.

Final drive chain lower but not as solid, nor a consistant.

Clutch basket is higher, but, in my experience, can come & go, dependant on how the clutch plates are randomly off center when the stack is clamped. (Clutch engaged)

kommando · Oct 14, 2023

Fast Eddie said:
You’re quite the collector Ken !

Very interesting picture, personally I don’t quite see how those strengthening mods actually strengthen the weak point ?

My hypothesis is that the cradles only break when another factor is added, ie loose engine to cradle fasteners.

They support the area of weakness by reducing the amplitude of the bending, this helps reduce risk of a fatigue crack despite not being directly at the thinnest point

Fast Eddie · Oct 14, 2023

kommando said:
They support the area of weakness by reducing the amplitude of the bending, this helps reduce risk of a fatigue crack despite not being directly at the thinnest point

Roger that.

But doesn’t it also create a potential weak spot between the stiffener and adjacent thin area ?

kommando · Oct 14, 2023

Fast Eddie said:
Roger that.

But doesn’t it also create a potential weak spot between the stiffener and adjacent thin area ?

As you suggest just welding a gusset where something has broken can just move the weak point to the edge of the gusset for a new cracking point. But in this case the extra metal is full height and supporting not just the top thin section but also the middle and bottom slightly stronger bolting points. By shortening the sections subject to bending it will probably be changing the resonance frequency out of a critical range as well.

MexicoMike · Oct 14, 2023

Belt drive...a solution for which there is no problem.

Yeah, even though CNW, which I have a huge respect for and have purchased many parts from, includes it as part of their E-start kit.

baz · Oct 14, 2023

MexicoMike said:
Belt drive...a solution for which there is no problem.

Yeah, even though CNW, which I have a huge respect for and have purchased many parts from, includes it as part of their E-start kit.

I agree
But I went to belt purely because of the difference in weight
There's nothing wrong with the standard setup

Heavy Vibration Issue

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