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* THE "CARL CLAMP" CLAMPING DOWN ON BENDING AND FLEXING FORKS ...
 * UNDERSTANDING WOBBLES, WEAVES & SHAKING ISSUES.

mar 2007
UNDERSTANDING WOBBLES, WEAVES, SHAKING,  SNAKING, FISHTAILING AND HANDLING ISSUES

Frame and swing arm
When you really start putting power to the rear wheel the swing arm and the frame flexes. The solution brace the swing arm ,brace the frame , stiffen the frame by replacing the rubber engine mounts and fit radial tyres....standard bias ply tyres belong on trucks.


Take a look at figure 2.

Front fork
The generally accepted handling fix concerning the tightening (or loosening of the steering bearings) generally works. I  say generally because it solves the standard wobble that occurs at about 35-45 mph when you accelerate or slow down in that speed zone.
Wobble motion

The weave occurs at around  115mph either in a bend or on a straight road and is generally a scary event causing you to slow down for fear of loosing control .
Weave motion

 I need to stress that it is very important to have your steering head bearings checked and adjusted. Just as importantly is to ensure that the big locking nut is properly tightened. If that nut is loose (even a little) it can cause sufficient movement that can set off a wobble /weave ...I speak here out of personal experience. Fitting a steering damper also works however it adds incremental stability and also is not a cure all solution and should be seen as a series of modifications to the entire package.

Done all the mods ?
 I think so ,except for the fork brace that is offered for sale by many Vmax aftermarket vendors. This device seems a thicker version of the standard device that hangs the front mudguard over the front wheel. The idea is that it braces the front fork adding stability....maybe it does ,I have never tried it.

Take a look at figure 1.


This flexing of the fork occurs in braking, accelerating, cornering or in combination of both. It seems as though the flexing occurs on the stanchion in the area below the triple clamp and above the fork slider. Modern bikes have much thicker (read less flexible) forks and it now seems clear why upside down forks do not flex (as much )as conventional forks since the USD forks are mounted in the triple clamps on the sliders and not on the stanchions. USD forks seem  better suited to high performance motorcycles.

Can we try to stop or minimalise fork flex ? 
Well short of fitting USD forks (costly), the other option is not to ride hard, brake hard or accelerate hard-something which is near impossible on a Vmax. I have a design for a possible cure for fork flexing which I am having machined at this very moment. When it is completed I will fit it, test it and submit my results for your consideration. If I can achieve this the Vmax will handle even better in corners and high speed stability.
I am optimistic that this will work on the standard Vmax fork in making it more sturdy and hopefully much less flexible. Also I have not seen such a device fitted by any Vmaxer anywhere on any web page and this may be a "Boerepatent" that may work for me and also for other Vmaxers.
(see follow-up article below)
Vmaximus maximus 
Carl Talbot

 

apr 2007
FOLLOW UP ARTICLES; UNDERSTANDING WOBBLES, WEAVES, SHAKING, SNAKING, FISHTAILING & HANDLING ISSUES

CLAMPING DOWN ON BENDING AND FLEXING FORKS ...THE "CARL CLAMP"

In my previous article  I concluded:

"I am optimistic that this will work on the standard Vmax fork in making it more sturdy and hopefully much less flexible.Also I have not seen such a device fitted by any Vmaxer anywhere on any web page and this may be a "boerepatent" that may work for me and also for other Vmaxers."

My Results

See attached the pictures of the device that I dreamed up and had machined .

The idea is to strengthen and brace the fork stanchions themselves, in the section directly below the clamps  up to just above the fork slider when the forks are completely compressed,thus restricting them from bending and flexing under  the immense forces of acceleration,braking and cornering.

I repeat again that all the previous modifications turned the Vmax into a better handling cruiser than it has any right to do.This is true insofar that Mr Max weighs at least 100 kg more than a sportsbike.Yes a sportsbike has aerodynamics ,is superior at speeds above 150 mph and also in very tight consecutive corners.In the real world Mr Max (piloted by a competent rider)will however embarrass many rookie(and intermediate ability) sportbike riders.This hooligan  packs enough muscle in the power cruiser arena to back up its looks...a heavyweight cruiser that handles like  an agile middleweight on steroids....a power sportcruiser. 

What did I set out to achieve with the clamp modification:

-to make the Vmax even more stable at high speeds

-to make the Vmax more stable at tight cornering , braking and acceleration

-Have I succeeded........the answer is  yes and apart from the clamps  functionality it really looks the business.

I therefore introduce to all South African(and overseas Vmaxers) a modification that has (to my knowledge) never been thought of or actually done before............................therefore beef up your fork and clamp down on bending and flexing with a  "Carl Clamp". 

ps.I  have lowered the handlebars on my Max and now have lower flat straight drag bars which are more conducive to faster cornering and high speed straightlining.It still looks and sits like a bad ass power cruiser and can turn from big lazy cruiser into mean hot rod at the drop of a gear and the twist of the throttle...a real Doctor Jeckyll and Mr Hyde. 

 Vmaximus maximus ,long live the power sportcruiser
Carl Talbot

----- Original Message -----

From: Carl Talbot

To: Hans

Sent: Thursday, June 14, 2007 4:42 PM

Subject: Clamps and Fin Maxers

 Your handling remarks between Hans V's HD and the Vmax is interesting insofar as the fork goes and the rubber mounts and I agree.

 On a  HD though the rubber mounts are there to dampen the vibrations.On a Vmax the engine is counterbalanced(hence hardly any vibration) and solid metal engine  mounts serve to make the engine an internal part of the frame and stiffen it up(frame brace too). If you ride a Vmax to the same limit as the HD's maximum performance then the standard Vmax is ok and should not show signs of handling problems.If memory serves me the engine performance from a Hog at 1450cc makes about 65 hp at the crank and a lot higher torque figure.Horsepower is what causes acceleration.The higher you rev the more the horsepower increases and the torque decreases. 

 Trucks and tractors don't have lots(relatively speaking) of horsepower or high reving engines. Torque is what trucks and tractors use to pull heavy weights like ploughs and trailers.A Vmax without Vboost makes about 85 hp(at 8500 rpm) at the rear wheel(about 100 hp at the crank and probably more torque than a HD). A Vmax with Vboost makes 145 hp(reving at 8500 rpm) at the crank and about 116 hp at the rear wheel.....that is approximately  two times as much horsepower than a Hog.The Vboost Vmax makes about 130 Nm at the rear wheel(at 6000rpm).The max has a relatively flat torque curve from 2500-6000 rpm whereafter it starts to drop as the revs increase.

 Obviously the HD frame ,fork and swing arm(and tyres) never has to cope with those types of power delivery....ever.Power delivery ultimately ends up in the tyres.Braking and cornering ability also depends on tyres.As I have said before if the Vmax is ridden like a slow lazy cruiser no mods at all ever need to be done.The problem is that the engine overwhelms the entire package of fork,frame,swing arm and tyres when the throttle is really twisted.The HD never has to face this problem.Most handling problems are more noticeable when you start pushing the higher levels of performance.

 I am very pleased that your Max now handles beter for you.If you do  ride beyond 4000rpm through the gears then radial tyres are better in terms of keeping the power controllable.Also if you live in a area of wide open spaces(with no hills)the standard Vmax is great.I have also  reached a point that my Max now handles and performs (excuse the pun) to the max and for me I am pleased at the result. 

 Regarding the web site I am extremely pleased.I somehow believed that things would snowball and get even beter...great news Hans.  

As regards the Fins it was very interesting.

 What I also noticed from the pics was that most of them did not have handling mods although one Vmax with many handling mods and also NOS.

 Carl


----- Original Message -----

From: Hans J P Knop

To: Carl Talbot

Sent: Thursday, June 14, 2007 6:50 AM

Subject: CLAMPS and FIN MAXERS 

Hi Carl

It seems to me that the weakest point always has been the flimsiness of the fork. My friend Hans' Harley, a heavy 300 kgs + bike, has thick USD forks and ordinary, simple, thin, old fashioned Cross Ply tyres. The engine is rubber mounted.When I had a ride on it recently, it felt solid, comfortable, with a good roadholding as well.

I am now happy with my Maxes' roadholding and don't find it necessary to make more improvements.

----- Original Message -----

From: John van Nieuwenhuizen

To: Hans Knop

Sent: Monday, April 30, 2007 1:47 PM

Subject: CARL CLAMP

Hi Hans,

I trust that you are well, I must compliment you on maintaining the site. I find myself going back more often. I keep an eye open for the date last updated.

Hans I have fitted the "Carl clamp" and can strongly recommend it. One must bear in mind that Carl and I have the "older" model having the 40 mm front forks with the single pot caliper.

I fitted the clamp this past week end and took Mr MAX on a trail run. The difference in handling is felt immediately. I have not done heavy braking so I cannot comment on the braking at this stage. I would normally encounter a slight twitch or noodle under acceleration through the V-Boost nearing the top end.

Not so with The 'Carl Clamp" I found the Brute gentle and very smooth all the way until I ran out of road. You can use your knowledge and imagination of the VMAX power and its capabilities to determine the speed involved during this exercise. I have as you know done most of the frame brace conversions and can recommend this clamp to all other VMAX owners.

Next on shopping list.Laser Jammer 

Till we chat again

VMAXIMUS GREETINGS

JOHN

PS keep one wheel on the tar.

Saturday, 9 June , 2007.

 

I have also fitted 2 Carl's Clamps to my Max ,and I must say, they perform well.

When you look at the pic of the lateral displacement effects you will understand that Carl's Clamps should make an inexpensive alternative to an U.S.D fork, and will be a great improvement to the fork's performance.


hans knop

----- Original Message -----
From:
marius swanepoel
To:
Hans J P Knop
Sent: Sunday, June 10, 2007 7:22 PM
Subject: Re: VMAXWORLD eNEWSLETTER No 18 (J-T) - CARL'S FORK CLAMPS INVENTION

hallo hans
i bought a 2002 v-max as you can see on my profile at v- max world.my previouce bike was a zx600ninja,it was a pretty good preformar in corners.i drove the v-max just as hard in corners but never ever experienced the flex u guys are talking about.is my v-max allready reinforced or is it just something everybody have in their heads about a v-max?

----- Original Message -----

To: Hans
From: Carl Talbot

Sent: Wednesday, June 13, 2007 8:42 AM

Subject: Clamps
Hans
Carl Clamp
I am pleased that the clamps are doing what they were intented for.The fork stanchions where definately bending and flexing in all directions under braking, cornering and acceleration.Thanks for the kind words from you and John.In my opinion  the clamps also look good on a cosmetic level.

After doing all the possible mods I had done,I realised that the front fork was a huge problem.John van Nieuwenhuizen and I debated USD forks however I was not prepared to spend almost R20 000 on a usd fork from the UK. I sat for many hours staring at the forks and came up with the idea of the fork clamps.It was merely a question of understanding the problem and finding a suitable cost effective solution.It is such a simple device and I doubt that it can be improved or simplified.I guess it can be cosmetically changed however the principle remains the same.

When I designed and fitted the clamps it was simply my intention to improve my bike.If other fellow Maxers want clamps that is fine.As I said previously it is possible to commission any machinist to make the clamps.I am just not sure that they can be made for cheaper than what my machinist charges.The price is R550 plus R30 for registered mail or R 90 for overnight via Speed services courier.I will take orders (if anyone is interested) in the same way that I did yours and John's.

Marius Swanepoel

As regards to Marius Swanepoel I am tempeted to  answer:

Welcome to the Vmax world and the ZX600 Ninja is certainly a very good example of a plastic sport racing bike and vmax can in all likelyhood never handle better than any modern technology lightweight machine.The vmax is just too chubby for that.That does not mean that the Vmax cannot handle around corners.At the Vmax rally there was a Vmaxer(I cannot remember his name) who cornered so hard that on both sides both his foot pegs where worn away.

Please read the technical tips page,it is loaded with all sorts of mods that according to several local Vmaxers and also legions of Vmaxers overseas, improve and enhance the Vmax even more.That said please remember that even in its most modified form the Vmax is essentially a heavy power cruiser on 23 year old technology.If you want the fastest top speed bike and the best track racer, purchase a new plastic racer every two years because next years bike will be faster.Weight is a big factor and Vmax will remain heavy,even if you chop as many things off as you can it will still be 80 kg plus heavier than modern bikes. 

No motorcycle jounalist would even dream of putting a 2000 model of any bike against a 2007 model of the same bike...the 2007 model is just too technologically advanced in all regards..the Vmax  cannot outbrake a lighter bike into corners..it cannot outperform a light sportbike around very tight corners and chicanes...it is not faster than 240 km/h top speed.It is however a Vmax..a legend ..an icon ...a bad motherf#@*r .Some of us who ride them, have improved them by 100% in handling without touching the engine.I know what a standard Vmax rides like(rode it like that for almost 2 years for  25 000 km) and I know what an improved Vmax handles like(I have done the mods one by one and can feel the difference and have done a further 46 000 km since).Why do I still ride a 23 old bike....because I can...because it is a Vmax.

I am pleased that you enjoy your Vmax and that it performs for you as well as your old bike.I also accept what you say namely that many people dismiss the Vmax as a bad handling bike and yes it probably does when unfairly compared to the handling of a modern bike.Ask yourself the question..."how many people are out there on the road on a 23 year old bike ?".

No one sneers at Mr Max.It might not be the fastest (anymore)but in 1984 it was and there was nothing like it.It started the craze for bikes that were exceedingly fast and the idea of a fast chopper cruiser hotrod is only now catching on.The Vmax was way ahead of its time. 

No your Vmax is not reinforced if is still standard and I assure you that in standard form it does flex in the swing arm,frame and fork.Furthermore the cross ply tyres on standard Vmaxes are truck tyres and are nowhere near the perfomance to be obtained from radial tyres .When you are on radial tyres the grip and performance improves and the flex of all the parts mentioned is more noticeble.Anyway welcome once again .
 Cheers
Ok Hans regards
Carl


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