After experiencing ill Handleing on many bikes over the years and in particular on my Lemans 1000 and California Stone.I thought i would share my experience as others i talk to and read about suffer the same dreaded Tonti weave while cornering.
My Lemans would gradually loose its renound stability from time to time.I would check the usual culprits,worn tyres,head stem bearings,fork action,swing arm bearings and tightness of all frame bolts etc
1 i have found that steering dampers,in particular the std black friction type fitted to many Tonti,s can cause bad handleing.They become worn and grabby,inconsistant friction,with age and dont allow a smooth steering action.Transferring unwanted forces back into the chassis.
In my opinion no Tonti(except maybe those with 16" front wheels) needs a steering damper.I have thrown all my dampers in the trash and have never experienced a tank slapper.Daytona included.
They dont improve handleing,they hinder it.If you insist on using one it would be wise to use a good quality oil damped type.
2 Badly worn,squared off rear tyres gradually decrease stability.
3 The most common cause of the dreaded Tonti Weave for me has been worn head stem bearings.
Too tight,can also be a problem.A little loose is not a problem.
This is not always obvious.Jacking the front wheel off the ground and rotating the steering stem,either by grasping the fork legs or handlebars doesnt always show a problem.
I have learnt to become very sensitive to feel for this check.
I hold the handlebar ends lightly with two fingers,close my eyes(it seems to help me for some reason) and very slowly rotate the steering from left to right, close to centered.
I am feeling for the slightest notch which will be felt with the wheel pointing straight ahead or a slight looseness as it centres followed by slight tightening just off centre in both directions.
Any abnormality felt,however small will indicate wear on the steering head bearings races.
Improved handling will be gained by replacing both bearings.
Dont be tempted to cheat by replacing the outer races only.They can be tapped out of the head stock easily,while the bottom inner race with rollers is a little more difficult and must be pressed,cut or pulled off.
Failing to replace all components wont resolve the problem as indentations will also be present on the inner races under the rollers.I tried being lazy,only having to do it all again.
The outer races will probably show dark vertical lines (as pictured above)where the rollers impact while the steering is centered.These can often be felt with your fingernail.
Replacing worn bearings will always improve handleing.
When cornering we turn the bars slightly until the required lean angle is achieved.The steering is offset slightly to retain this arc.If we have slight grooves in the bearings the steering wants to return to this looser worn spot,the steering straightens,but we want the bike to keep cornering so we make slight adjustments to the steering and it wants to slip back into its worn groove again........
This is my theory atleast.
If you are experiencing cornering flex or wobbles and havnt replaced your head stem bearings in say,the last five years or dont remember ever replacing them.
This is often the No 1 overlooked cause.
I replace my head stem bearings between 3-5 years and always notice an improvement.
My ill handleing 2001 California?
I rebuilt the forks with cartridge emulators,rebound mod and the correct weight oil.
Fitted new tyres.
Replaced Ikon shocks with Hagon Nitro,s.
These all improved the wobble but...
The biggest improvement i got in handleing was replacing the head stem bearings.
Yes,i have a short memory....
Fresh steering head bearings are the key for stable handleing Tonti,s
My Lemans would gradually loose its renound stability from time to time.I would check the usual culprits,worn tyres,head stem bearings,fork action,swing arm bearings and tightness of all frame bolts etc
1 i have found that steering dampers,in particular the std black friction type fitted to many Tonti,s can cause bad handleing.They become worn and grabby,inconsistant friction,with age and dont allow a smooth steering action.Transferring unwanted forces back into the chassis.
In my opinion no Tonti(except maybe those with 16" front wheels) needs a steering damper.I have thrown all my dampers in the trash and have never experienced a tank slapper.Daytona included.
They dont improve handleing,they hinder it.If you insist on using one it would be wise to use a good quality oil damped type.
2 Badly worn,squared off rear tyres gradually decrease stability.
3 The most common cause of the dreaded Tonti Weave for me has been worn head stem bearings.
Too tight,can also be a problem.A little loose is not a problem.
This is not always obvious.Jacking the front wheel off the ground and rotating the steering stem,either by grasping the fork legs or handlebars doesnt always show a problem.
I have learnt to become very sensitive to feel for this check.
I hold the handlebar ends lightly with two fingers,close my eyes(it seems to help me for some reason) and very slowly rotate the steering from left to right, close to centered.
I am feeling for the slightest notch which will be felt with the wheel pointing straight ahead or a slight looseness as it centres followed by slight tightening just off centre in both directions.
Any abnormality felt,however small will indicate wear on the steering head bearings races.
Improved handling will be gained by replacing both bearings.
Dont be tempted to cheat by replacing the outer races only.They can be tapped out of the head stock easily,while the bottom inner race with rollers is a little more difficult and must be pressed,cut or pulled off.
Failing to replace all components wont resolve the problem as indentations will also be present on the inner races under the rollers.I tried being lazy,only having to do it all again.
The outer races will probably show dark vertical lines (as pictured above)where the rollers impact while the steering is centered.These can often be felt with your fingernail.
Replacing worn bearings will always improve handleing.
When cornering we turn the bars slightly until the required lean angle is achieved.The steering is offset slightly to retain this arc.If we have slight grooves in the bearings the steering wants to return to this looser worn spot,the steering straightens,but we want the bike to keep cornering so we make slight adjustments to the steering and it wants to slip back into its worn groove again........
This is my theory atleast.
If you are experiencing cornering flex or wobbles and havnt replaced your head stem bearings in say,the last five years or dont remember ever replacing them.
This is often the No 1 overlooked cause.
I replace my head stem bearings between 3-5 years and always notice an improvement.
My ill handleing 2001 California?
I rebuilt the forks with cartridge emulators,rebound mod and the correct weight oil.
Fitted new tyres.
Replaced Ikon shocks with Hagon Nitro,s.
These all improved the wobble but...
The biggest improvement i got in handleing was replacing the head stem bearings.
Yes,i have a short memory....
Fresh steering head bearings are the key for stable handleing Tonti,s
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