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The Definitive USD Fork Conversion for Sprints Thread

307K views 640 replies 85 participants last post by  UKEXPLORER 
#1 ·
Foreword:
Please note that this thread is only to offer some guidance for anyone who might wish to entertain a retrofit to their Sprint front suspension - this in no way constitutes any offer or solicitation to provide any parts.
The main focus is to provide some information on how to do this yourself. It also assumes anyone undertaking such a project has some mechanical engineering aptitude and decent knowledge of motorcycle mechanics with ability that goes beyond basic maintenance.
Do this modification entirely at your own risk & consequence.
Yet hopefully, there is at least one configuration that is quite readily available - and at reasonable cost - for execution by anyone with rudimentary skills and the appropriate toolset. I also caution that you validate any dimensional information for yourself and I make no specific guarantees on anything that follows! There are many different permutations and differences between model years - so all information does not necessarily translate universally!
Recognize that there will be geometry changes predominantly associated with the shorter offset of the triple clamps, resulting in longer trail.
See the tutorial later in thread on rake/trail dynamics.

I'd like to particularly acknowledge our very own OldnDumb who gave tremendous input to one of these projects (the first validation of the TLS conversion) and has provided many of the images you will see below.

Hopefully you'll read on!!!


After helping a few people through some USD fork conversions, I thought I might put some notes together for anyone who might want to consider this option.

Conversions I have personally been engaged in, include:
2004 Sprint RS with 06 GSXR1000 forks
2000 Sprint RS with 06 GSXR750 forks
2000 Sprint RS with Hayabusa forks
2006 ST Sprint ST with TLS forks
2005 ST Sprint ST with 06 GSXR1000 forks.

Note that most of the work in completing these bikes was done by their owners - I essentially provided the guidance & dimensional information & in some instances some special parts.

So we have a smorgasbord of Models across generations as well as both conventional & Radial Suzuki Front ends

Here are a few pictures from those listed above to give you an idea of how they at least look when completed, never mind perform: I think you'll agree that you would be hard-pressed to consider any of these looking any less 'finished' than original showroom configuration.

06 ST with TLS


00 RS with 06 GSXR 750


04 RS with 06 GSXR 1000


05 ST with 06 GSXR1000


00 Sprint RS (naked) with 05 Hayabusa
 
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#2 ·
First some fundamentals regarding different Suzuki forks.

For the purposes of this thread, we will focus on late-model GSXR Radial forks and the conventional braked TL & Hayabusa forks.

Here is a table of dimensions that was created on another forum




TL/Hayabusa Forks:
The main focus for this thread will be on these - the TL and Hayabusa make excellent donors for a very affordable conversion for a Sprint - one of the key assets for this kit is that it involves very few custom parts and you do not need to purchase brake calipers - the OEM Triumph calipers will bolt directly on to either of these variants!
Of course if you wish, you may also install the 6-pot Hayabusa calipers as additional feature - but it is not necessary as a pre-requisite. That can be added at any time competely separate of the primary conversion as/when the mood takes you or funds are more available.

The other big advantage over GSXR forks is that these use 320mm rotors so no radial spacing is required to accommodate a different size rotor from what they had when on originating equipment. Lateral or axial spacing is also much more easily accommodated without custom parts.

Hayabusa forks are the most readily available covering a wide manufacturing range from 99 through 07 with very little changes. Also more affordable in their own right versus the popular GSXR Radial forks which are being snapped up the TL and SV crowd in their quest for 'something different'

The TL's and Hayabusa Kayaba forks have minor differences but are dimensionally identical regards the retrofit perspective. The fork legs and Triple trees are intechangable with each other.
The three variants triples are all 32mm offset.
Hayaubsa and TLS are preferred for the lower triple clamp and would recommend against the TLR which is probably less desirable.

OEM Spring Rates are 740g/mm for the TLS;
850 for the 'Busa;
934 for the TLR.
(OEM Sprint vary by year - 750 for the earliest series and Progressive rate on the 05+)

All Tls (R & S) have silver outer tubes; Hayabusa are either silver or gold depending on vintage/model.

All forks are same dimensions, 50mm diameter at top clamp, 55mm dia at bottom clamp.

GSXR Radial forks.
The first differential is that the 600's and 750's are Showa and the 1000's are Kayaba. All since 03 (1000) and 04 500/750 have radial calipers.
We won't discuss non-radial GSXR forks from previous generations - the caliper mounts are different from their brethren above and consequently the Sprints, so not ideal donor consideration (although possible)
04/05 600 and 750 are identical, 850 g/mm springs;
06 + 600's are gold and have 850g/mm springs;
06+ 750's are black and have 1000g/mm springs;
03/04 1000 are gold and have 850 g/mm springs
05/06 1000 are bronze and have 950 g/mm springs;

Other than 03/04 1000 at 32mm offset, all the others have 30mm offset.
03/04 1000 and 04/05 600/750 use 300mm rotors - all forward use 310mm rotors.
All Sprints are 320mm rotors so this needs to be accounted for with a radial spacer between caliper and fork mounting. (more on that later.
06+ Showas have 53mm lower triple fork leg diameter - all others are 54mm - must be careful of mix n match between legs & triples! Also the stem diameter at the top clamp is different so again all are not common!

So here are some of the key features why the TL/Hayabusa variants offer much less complexity to install vs the GSXR:

Hayabusa/TL:
  • Same Rotor Size
  • Utilizes OEM Calipers
  • Same Caliper Mounting
  • Simple Axle/Caliper Spacers
  • Simple adaption of OEM TLS top clamp
  • Easy integration of axle with speed sender (through '04)

GSXR:
  • Requires Calipers as well as forks
  • Requires custom Caliper Spacers
  • Requires custom Rotor Spacers
  • Speedo drive (through 04) requires custom machining
  • Custom top clamp required


So when all that table is dissected and analyzed, The TL/Hayabusa option become the no-brainer option for the Sprint really
Affordable and no serious custom parts, just some simple spacers


Caution! Avoid the 97 model-year TLS forks - these reportedly have inferior valving.
(improved in subsequent years)

.
 
#3 · (Edited)
So here's what we're going to be working with:

05 Hayabusa forks/tree

749768








(Gold & Silver Busa are same specs - just colour difference only)

98 TLS forks/Tree



The silver TL and silver Busa forks look similar but actually have different specs (see the matrix)


Here is a crude dimensional drawing on how the 99-04 Sprint wheel works in a set of 'Busa/TL forks which accounts for the speedo drive in the right side of the wheel

749765


The first huge advantage we recognize is that both Triumph & Suzuki use 25mm axles which means the Triumph wheels can be readily installed on a Suzuki axle and we only have to worry about axial spacing to center the wheel on bikes mid-line.
No messing aorund with wheel bearing worries!

The right side wheel bearing is inset 8mm vs the left bearing and the length of the speedo drive is 35mm; net spacing on right side is thus 35 -8 +2 = 29mm; right side spacer will also net at 29mm.

In order to achieve this the OEM axle from the 'Busa/TL is first reversed so the collar is now on the right, rather than the OEM Suzuki configuration of the left (however the axle is symmetrical so all works out)
Our object is to use the right fork as the frame of reference and pull everything up tight against that leg to center the wheel.
Recognize that the left side spacer thus is non-critical as, regardless of whether spacer on that side is short or long, the axle will adjust accordingly to pull up tight on right side.

To accomplish correct centering, the collar nut is machined to remove 14.5mm from its overall length - this is a simple lathe operation. The net result should leave 2mm proud of the inside of the fork leg when the outside bushing surface is tight against the right leg.
For the left side spacer, ideal dimension would be 35mm OD (to fit the Sprint wheel grease seal) by 25.05mm ID (clearance for 25mm axle) 12.5mm (29 - 16.5) long - in reality, this could be anywhere from 10-15mm long. If you are stuck to have a new spacer made with the ideal OD for the wheel bearing grease seal, note that you could simply use the piece cut from the collar transferred to the left side! This piece is only 32mm diameter so will not be tight against the inside diameter of the grease seal but will correctly position the wheel regarding spacing.

749766


Note that you can just make a very simple spacer as per above
I took it a step further and created a 'sleeve' spacer (see image below) - the smaller ID section is 12.5mm long and the axle slips inside it (at the larger ID) and so aesthetically you have appearance of a single spacer. If overall length is 29mm then it correctly sets the right leg tight against it (I would actually go 1mm small so that you are not actually setting the right leg directly against that OD)

749767


749771


Late Model (05+) wheel spacing:

This one is also very easy to accommodate - on the 05+ wheel there is no speedo drive to contend with of course, so contrary to the speedo drive model, bearing spacing in the wheel is symmetrical.
I haven't done a drawing for that wheel, but here is the dimensional information:

The space between the St wheel bearing outer faces is 108mm. The space between the TL forks is 168mm.
The right and left TL spacers (axle & axle collar) are effectively 16.5mm each side.
Fitment of the ST wheel to the TL fork requires a total spacing of 60mm split for each side i.e 30mm.
Thus an additional 13.5mm spacer is needed per side vetween the wheel berarings and the built-in axle and collar nut spacers.
This means the axle spacer requirement is 2 each at 13.5mm long by a 25.05mm ID dimension.

(TL fork spread 168mm) - (ST wheel 108mm) = 60mm total gap
(60mm gap) - (Tl spacer total 33mm) = 27mm
(27mm) / 2 = 13.5mm additional spacing required ea side.

You have the option of either having two completely new spacers machined (35mm OD X 25.05mm ID X 13.5mm) or use the original ST axle spacers by turning them down to a new 13.5mm length. These are already the correct OD for the gease seal and ID for axle so this is an easy route to follow.

So regardless of whether old or new wheel is used, pretty simple lathe machining exercise to create the spacers required for the axle.

* There have been several questions/doubters on the new spacer dimensions because the OEM spacers on the '05+ are 'handed', with a wider spacer on the the left side.

The OEM left fork has a 2mm offset (or inset actually) - most likely to accommodate the ABS pulsar rotor/sensor - which is why the OEM left spacer is wider.
(OEM forks identical for ABS or Std.)
This is NOT the case for the conversion forks -
The TL/Hayabusa forks are symmetrical and the new spacers are identical on both sides.


Rotor/Caliper Alignment:

The next consideration is centering of the rotors in the calipers.
Regardless of old or new model Sprint wheel, the rotors are 129mm on center. The TL and 'Busa variants have wheels which place the rotors 134mm on center axially with respect to each other.
That means that with the Sprint wheel placed in the TL/'Busa forks with its own Suzuki triple tree, the rotors will be 5mm/2 = 2.5mm too far inboard (equally divided per side).

We have two ways to resolve this:
a) a 2.5mm spacer between rotor & wheel hub on either side
b) a 2.5mm spacer to move the caliper inboard.

Well this decision is no brainer - a spacer to move the calipers inboard is nothing more than an M10 washer, against making a rotor spacer would involve a custom milling operation.
(note that we can easily move the conventional caliper axial on its mounting versus the radial, which is easily spaced radially but impossible to adjust axially)
Note that this again is ideally 2.5mm spacer between the caliper and the fork mounting - however some tolerance to this is OK as the pistons will accommodate any discrepancy form absolute center. It is important however that you match up the thicknesses with a micrometer or caliper in order to ensure perpendicularity to the mounting. i.e. whether ALL are 2.0mm or ideally 2.5mm is moot, as long as they are matched.









The net result at this stage is we now have wheel/rotor/caliper/axle spacing all accommodated fairly with only some very minor customization.
 

Attachments

#596 ·
The OEM TL Spacers are incorporated into the axle and collar nut (i.e. these components each protrude inboard by 16.5mm from the inner face of each leg)

The space between the St wheel bearing outer faces is 108mm. The space between the TL forks is 168mm.
The right and left TL spacers (axle & axle collar) are effectively 16.5mm each side.
Fitment of the ST wheel to the TL fork requires a total spacing of 60mm split for each side i.e 30mm.
Thus an additional 13.5mm spacer is needed per side between the wheel bearings and the built-in axle and collar nut spacers.
This means the axle spacer requirement is 2 each of 13.5mm with a 25.05mm ID dimension.
You can cut down Sprint spacers or make from scratch
 
#4 ·
Next up is installing the Triple Tree in the Sprint Steering Head.

Again, the intent of this thread is to provide the dimensional information on what is required - I am not including specific instruction on how to remove your OEM forks and triple trees.
My premise is that you must be at least capable of this if you plan to undertake this retrofit, so I'll refrain from specifics unless there are some particular hints/tips that can be offered in the execution.

It goes without saying that some means of being able to support the front end of the bike is required, such that you are able to completely remove the triple tree. So any form of lift that relies on the forks or triples can only be an intermediate step.

If you have crash bungs this is a great support point however - lift the bike with a conventional front-end lft then lower it onto the crash bungs supported by axle stands on blocks.

It may not (likely not) be required to remove the fairings - that will come down to personal choice.

Remove the entire OEM front end - calipers/wheel/fender/bars/top clamp/fork legs/triple tree pretty much in that sequence

Then you need to remove the old bearing shells from the Triumph steering head.

Steering Head bearings.

The bottom bearing is actually the same size on all the Suzuki variants and the Triumphs - 30/55/17. The only difference is Triumph uses a tapered roller and suzuki uses ball races.

For the top bearing, on the 05+ the bearing is also the same as the Suzuki top bearing, again 30/55/17.

So to purchase new bearings for your late (05+) model install you can order bearings & dust seal kit for either the 'Busa/Tl or Sprint - will be the same parts.

For the 99-04 models, the top bearing is a different size however;
but there is a custom bearing available that has the required 30mm ID for the Suzuki stem and the 52mm OD required for the Sprint Steering head. This bearing is an NTN 4T-CR-0643 (30 x 52 x 16) which is speciality item not readily available - but is at the source mentioned following.

I recommend AllBallsBearings for your Tapered Roller Bearings

All Balls Better Bearings & Components
Power Sport Inustries, Inc.
P.O. Box 437
822 N Reading Ave
New Berlinville, PA 19545
Ph: 610-473-0505, 888-228-3323
Fax: 610-473-8411, 888-552-0557
www.goallballs.com

As aforementioned, you can easily order these on-line if you have a late model Sprint by simply specifying the Hayabusa kit - these come compete with dust seals and bearings.

For 'Busa, this is simply a 22-1003 kit on a late model Sprint

For 99-04 Sprint,
(Bearing / Dust Seal)
99-3519 / 33-1003 (30-55-17 mm)
99-3521 / 33-1005- equivelant to NTN 4T-CR-0643 (30 x 52 x 16)

This is actually available as a kit for a Yamaha model, kit # 22-1050:

Go to http://www.goallballs.com
Do a 'product look-up' on 2008 Yamaha RoadStar Warrior
Steering Bearing Kit is 22-1050.


You can buy directly on-line - the 22-1003 for late model bikes is $33 and the 22-1050 for the 99-04 is $37 (each is plus $7 shipping)


Bearing Removal from TL/'Busa Steering Stem:

This is probably the most onerous part of the whole job!

Again, particular credit to our own OldnDumb for the procedures and pictures on removing & installing bearings:

You can use one of two methods:

One is to press the steering stem out of the bottom triple - in the action of pressing it through the bottom, it presses the bearing off the stem. One of my my good friends swaers by this method - but then he has a press in his shop!

Alternatively you have to pull the bearing from the stem in situ.
This can be aided by cutting through it with a dremel - need to be careful to not cut the stem of course!
Start by using a tapered chisel between the dust seal and bearing, working around the perimeter to start it up the stem.



I actually managed to get my 'Busa bearing off without using a puller, just using progressively bigger wedge levered under the bearing - on others I have not been that lucky!!!

Bearing Installation Tips:

1) Seat the new bearings in the steering head both top & bottom;
Use a threaded rod, long enough to extend all the way through from top to bottom,* a washer over the bearing and nut at each end; then simply tighten on the nuts to pull the bearings into the seats. This ensures that you pull them in square & also get them seated fully. Then remove the inner bearing races until ready to install the tree.

2) To press the new bearing onto the stem, use a similar technique - this time however, slip a length of conduit pipe over the stem pressing on the bearing center; again, slip the threaded rod up through the stem, place washers & nuts* and tighten down again to fully seat the bearing.

Important note: REMEMBER TO INSTALL THE DUST SEAL BEFORE PRESSING THE LOWER STEM BEARING!





One item you can use under the conduit to press the stem bearing is the old race - cut a slot in it first so it doesn't get pressed on too! (You can also see that detail in the picture above)



With the bearings on the stem & the outer shells in the steering head, you can go on & install the complete triple tree, fork legs, wheel, axle and calipers at this stage.

Follow protocols for tightening head bearinsg of course
Note that there is a washer that installs between the load nut and the lock nut of the steering stem.

That concludes the first main part of integrating your 'Busa or TL forks into your Sprint frame.
 
#5 ·
Top Clamp:

There is one ideal candidate for top clamp for the Sprint and that is from the Suzuki TLS model.
It of course is perfect spacing & offset for any of the TL/Hayabusa combinations but additionally has a center igniton mount that can be readily adapted for the Sprint.



This one above has also been drilled to accomodate upright bar risers (See Post # 39) - this one will be on a 'naked' style Sprint. Note also that it polished up really nicely to a bright finish beneath the original anodizing which was sanded off.
Note that most of these will also have a threaded hole in the top: this is to accommodate a recall on the TLS whereby a steering damper was utilized. OnD made excellent use of that to install a RAM mount for GPS (the 4 images per post limits including that here but I'll show that in a later thread among other considerations/options)

There are however some modifcations that are required to both the TL clamp and also the ignition assembly itself.


First off, is aligment of the ignition in the clamp.
There is a different spacing between the ignition ring and mounts (with respct to the steering stem) on the Sprint versus TL clamps.
Although the difference is 9mm even 5mm removed will provide adequate clearance.
Also, the ignition mounting posts are longer on the TL clamp which places the ignition well below the top surface. This dimension is not a critical one, as the lock 'stop' is a vertical bar on the steering head; so the the ultimate vertical position of the lock is not critical, just so it looks good aesthetically.

To accommodate the fitment, two machining steps are necessary along with some simple rat-tail-filing of the ignition mount bracket.
1) Machine 5mm off the locking barrel and lock pin - this allows the ignition to clear the locking bar on the steering head
2) Modify the holes on the ignition mounting tabs - these need to be elongated inward and forward to position the ignition to be both centered in the ring and at correct spacing to bolt onto the TLS top clamp.
3) Machine 10mm off the ignition posts of the TLS clamp - this allows the ignition to come up flush with the top surface of the clamp





Note that even with machining 5mm off the locking pin, the steering lock will still function in the new configuration.
So for those concerned about security, this will continue to be a completely functional feature.

.

See posts 37 & 38 of this thread for futher detail on the ignition & top clamp modification

.
.
 
#6 ·
Next Up is consideration for steering stops

The simplest method of all may as trivial as just a rubber bumper pad on the frame and letting the forks to frame be the actual steering stop.
Now recognize that a steering stop is nothing more than an element to stop the bars contacting the tank in normal operation - the stock ones on a lower triple don't do a whole lot in a wreck and you'll frequently see them sheared off on forks for sale on EBay - even when the forks themselves 'appear' undamaged! (which is reasonable - a small cast nubbin is not going to withstand much load in a front collision and you'll have bigger things to worry about) No they're only there for parking maneuvers and low speed drops.
A quick test fit on DaBrew's RS showed that the upper fork legs will contact the frame with nothing else getting in the way.
So I think a pad to simply cushion the metal - metal contact between your forks and frame would suffice quite nicely.
In his case actually, there will be some delrin lamp brackets on the legs and these will actually be first point of contact on the frame - so these will be an inherent stop without actually even adding anything specifically for the purpose!


Here is another method which may be the best solution:

This method will relocate the steering STOPS away from the top of the steering head, to operate at the bottom triple clamp.
This will leave the fixed frame stops at the top of the steering head redundant for this purpose.

Here are the stops I designed and installed on my TL - it will be essentially the same for the Sprint.
These simply operate against the rear edge of the lower triple clamp.
They were designed with an offset mounting hole, which allows adjustability

Only difference for the Sprint is that there were pre-existing tapped holes on the TL frame (for the horn mount), although I took these out from the original M6 to M8 for additional strength.
It will be the same on the Sprint, except the holes will need to be drilled & tapped.
Means of course complete flexibility in where you position them.

You should be able to get these from Zoran at TWF, along with the axle spacers.




As you can see from the picture below, there is a lot of real-estate to work with on the Sprint - unlike on my TL (above) where it was a compromise because of the radiator!



.
 
#7 ·
Fender:

More options here for personal choice/taste.

If you look back to the TL and Hyabusa pics earlier in thread, you'll see some subtle differences in the fender mount.

Now - anyone who has seen a Hayabusa fender would not dream of putting such an ugly piece of plastic on a beautiful Triumph Sprint!
All personal taste of course, but take a look at 'Busas and make your own mind up.

Now for TL forks, it is a straight simple choice of getting a fender to match the forks - TLS look a little more streamlined than TLR, but either will fit. Of course you can use OEM sourced new or used off EBay or go with after-market Carbon Fibre

One excellent choice as displayed on OldnDumb's gorgeous completed specimen is by Coerce, Japanese company.
Even with shipping from Japan I believe he had it in hand in less than a week!



You can also see from image above he went with the optional Gold Hayabusa 6-pot calipers - but again this is purely personal - the OEM Sprints will be a direct bolt-on.

This is OEM TL fender with rattle-can paint job.



For the 'Busa forks, you can either go with the Hyabusa fitment - some of the after-market variants may not be quite so bulbous - or you can modify the fork bottom to take a TL mount fender.
This is approach we are taking for DaBrew Sprint with the '05 'Busa front end.

You need to trim the top mount (this is unused if using the TL fender) flush with the mounting arm and create a new bottom mount by drilling/tapping an M6 hole. The original bottom mount is unused and may either be cut off or left in place - it does not interfere with the TL fender.



 
#8 ·
That now leaves bars as a personal selection choice.

Bars:

Simplest option of course is to simply bolt on Suzuki clip-ons - all Suzuki bikes with USD forks utlize 50mm clip-ons. They do vary somewhat from model to model with subtle differences in the orientation/angle of the bar.
Hayabusa are the exception - they use a unique system that is similar in some ways to the Sprint with bars that mount directly to their own specific top clamp. It may be possible to integrate this system instead of using the TL clamp but you'll need to figure that one for yourself.

You can see that beyond the base configuration there are several permutations of options (fork choice/stops choice/fender choice/bars choice) so it is unlikely two bikes - even of the same model - will end up identical.

As shown in a previous post, on the naked bike (and this will work equally well for faired bikes) the TL top clamp is drilled to take conventional bar risers. There you have infnite choices of bar riser heights and bar bends.
Either conventional bars, or these from Suburban Machinery might be one option. These are very popular with the SV guys.
A little higher than clip-ons yet not as high as upright bars.

These clip-ons from Swatt Motorcycle are very affordable and come in a variety of rises. They will place you quite a bit forward or normal position of course.

And of course there are other variants of riser clip-ons like Convertibars, Gilles, ABM etc.

Here are some examples:

Convertibars



Suburban Machinery




Upright Bars





So there is a lot of individuality when it comes down to the selection of bars and really that is going to be personal preference in terms of taste, comfort and budget.


That pretty much wraps up the basic guide.
This should be readily do-able for well under $500 total with modest investment in the after-market department.
Of course you can easily blow that upwards when you add calipers, carbon fibre, exotic bars etc but you don't have to bite all that in one go just to get functional and like any other progress of mods, enhance it as/when your budget dictates.

You also open yourself up to further tuning options to enhance the forks even further with valve kits etc which are much more readily available for these units; and of course you have the tunability of compression & rebound damping as well as pre-load adjustments.
Again those are later considerations if you feel you need them - you should instantly notice a considerable improvement versus the OEMs without doing much other than installing and dialing in to suit your own preferences.


Minimum Project List:

Hayabusa or TL forks complete with Triple Tree and axle
TLS Top CLamp
Fender
Clip-ons or bars/risers
Steering Head Bearings
4 x M10 Washers for Caliper Mounting
M8 bolts/spacers for Steering Stop
Machining of Ignition and Top Clamp.
Machining of collar nut and axle spacer(s) (depending on Year/Model)


ABS Brakes

And last consideration is accommodation for ABS Brakes on the late model Sprints.
The ABS control system will work with any caliper - whether OEM or Hayabusa replacement 6-pots.
The key control items at the front end are the Pulsar ring and Pulsar sensor which detect the front wheel speed compared to the bike's overall speed.
(Detects locking situation)

OEM set-up:



From service manual (14.64), the pulsar spacing to the ring should be 0.1-1.5mm.
And of course the pulsar needs to be centered in the ring slots.
Design criteria therefor is to create a mounting bracket for the pulsar that positions the sensor accordingly.

I conceived the following design to accommodate mounting the pulsar onto the TL/Hayabusa forks.
Incorporated in the design is capability to accommodate adjustment for the sensor spacing.

Acknowledgements to dclarson for his measurements and prototype build work from my design.





.

Happy to answer any questions at this point.

.
 
#9 ·
Excellent thread DEcosse & thanks to OnD for the pics.

Not that i am 'going' to try this myself... (although I am sorely tempted!!!)

Are there any issues with using the 'donor' bikes original wheel?

Cheers, G :D
 
#10 ·
..Are there any issues with using the 'donor' bikes original wheel? ...
If I understand your question correctly G (I would define donor as the Suzuki - source for the forks) , perhaps you misunderstand - you use your own Triumph Wheel - whether early model or 05+
Early to late is slightly different but that is accommodated in the axle spacer design as noted in post #3 & post #4
 
#11 · (Edited)
Hi DEcosse,

I did see the post about the spacers...

I have never liked the design of the standard '05+ Sprint wheels and figure they would weigh more than the GSXR's for example...
so was just curious about using the donor bikes original wheel (assuming same size as Sprint) guessing/assuming that it may be lighter than the Sprint's. it may also allow the option of an aftermarket wheel that my reduce unsprung weight even further...

Cheers, G :D
 
#12 ·
...so was just curious about using the donor bikes original wheel (assuming same size as Sprint) guessing/assuming that it may be lighter than the Sprint's...
OK - understand your question now. Good question.

You could adapt to the late model Sprint but earlier would not be an option because of the speedo drive.
Early GSXR wheels or Hayabusa/TL would be straight bolt in and easier to adapt re axle spacers using OEM Suzuki parts - however just as heavy if not heavier than the 05+ Sprint wheels.
Late GSXR wheels - which are lighter only have 310mm rotors so special race rotors would have to be purchased to match up with the 320mm caliper mounting.
Another issue of course if matching up a rear wheel - not a fan of mis-matched wheels personally.
For aftermarket of course then by all means a Hayabusa front fit and Sprint rear would be the perfect combo and no customization of spacers regarding axle/calipers required.

You can adapt anything if you have a mind to it. But one of the main purposes of this exercise however was to provide a cost-effective suspension alternative with minimal additional requirements to the original equipment other than necessary - but of course it is possible to open up the scope beyond that to whatever the ultimate desire might be.
 
#16 ·
Ken, after what I went through with the 06 sprint fork swap I think that Im all set for a while. However my constant need to tinker and improve will eventually lead to a USD upgrade. Pops probably wont be to happy letting me use his garage again (kinda just dropped in when he was on time last time around) but when I get my own garage the wheels may start rolling again!:D
 
#17 ·
Excellent fork swap thread! Thanks DEcosse, OND and everyone else who contributed ideas and pictures. I have a set of tls forks in the garage and thought it would be much more complicated than it is. Great pics and instructions. Cheers, Maury.:D
 
#18 ·
Hi Maury - thanks for the nice PM

We'll look forward to seeing your forks come together with the bike!
Keep us updated on the progress! With pics of course!
If there are any specifics you need further clarification on, be glad to help if I can.
The TL's of course mean the 'good' fender just bolts on, no mods to the legs required. :p
Do you have idea about your bar choice yet?
 
#21 ·
tls swap

Ken, thanks for the offer, I may take you up on it. I'm going with convertibars or maybe lsl with risers. have seals and bearings coming. it will be a few months before i get all the parts together. will take pics as i go along. You have made it so i can get everything ready to install with much less downtime for the Sprint. Cheers, Maury :)
 
#22 ·
... I may take you up on it. I'm going with convertibars or maybe lsl with risers. ...
Do you have the TLS top clamp already?
Or just forks & Triple Tree?

If the former, you might save the money on the LSL kit - I simply drilled the TLS top clamp as you'll see in post #6.
It is about 7mm thick there so plenty of material to work with & be substantial.

Then all you need to add are risers and bars of your choosing - you can even go with Fat (29/22 Conical) Bars if you like (LSL clamp kit has only 22mm, no choice there).
I have Rizoma bars & risers on an OEM GSXR top clamp on both my TL & SV (well actually the SV is a 'std size bar on OEM SV risers while the TL has the Rizoma risers and bars) Risomas are super nice (have them on all three bikes!) but they are expensive.
At BikeBandit - where you can use our TriumphRat -10% coupon! - you can get ProTaper Risers and Renthal or Protaper Contour or Protaper Evo bars for already discounted prices less ANOTHER 10%!

Of course the Convertibars - like OnD's have the advantage of adjustability. Not cheap though!
OnD won't mind me saying - he already had made the Convertibar switch with his OEM forks.
So his delta for the fork conversion 'only' involved the new 50mm fork clamps which he was able to buy stand-alone
(nice feature by Convertibar to allow this without having to buy full new kit!!! )

.
 
#24 ·
While I appreciate the kind words, DEcosse deserves all credit. He was the one that did the computations that determined the TL set would fit. All I did was the grunt work and the money.

While I did replace the fork seals, I left the springs as they were to determine a baseline for future enhancements. I played around with the settings until I arrived at something that suited me around town. I am not a suspension guru, but I know that it was a big improvement over the ST forks as regards keeping the rubber in full contact with the road.

I have done two track days with the stock TL forks and am satisfied with them. The first 30 minutes had me a bit concerned, but after playing with the adjustments I was confident enough to get edge to edge use of the tires. A better rider would benefit from a re-valve kit, and would drop their lap times. But since I am not an expert rider, I am happy with it as is.

My hat is off to DEcosse for his efforts and willingness to share his research, computations, and advice. :thumbsup:
 
#25 ·
DEcosse said:
.... one of the key assets for this kit is that it involves very few custom parts ...
I'd like to revist this statement from the opening post, which will help define all of the requirements for customization.

Actually there are a sum total of ZERO parts that have to be made from scratch, or even need the complexity of any mechanical drawings!

There are 4 parts that do require some minimal machining work - I would estimate all four should be readily done in an hour by anyone with access to a lathe and a mill.
(can even be mini bench top tools or simply take them to a machine shop).

So take these parts for execution all at the same time - they can even be done while your Sprint is still intact (unless you utilize your original Sprint axle spacer(s) as donors) other than the time you need to remove the ignition - which can be re-installed again, even modified.

These parts and their modification:
1. Ignition Assembly
Machine 5mm off the locking pin (both pin & housing)
Elongate the mounting holes with a file to fit the TLS clamp posts.

2. TLS Top Clamp
Machine 10mm off the mounting posts
Optional - add holes for bar risers.

3. Axle Spacer(s)
One required for early model (12.5mm long)
Two required for late model (13.5mm long)
Either sacrifice the original(s) from your Sprint or buy new ones if you want to keep your bike operational. ($11 for new spacer)
In either case, just machine to length.

4. Collar Nut (Early Model Only requires this - late does not)
Machine collar nut length to remove 14.5mm.
Leaves new length (from inside face of flange) at 58mm, new net will be 43.5mm

5. Bottom Triple Mod (Optional)
If you're going to the machine shop anyway, you may wish to get the OEM steering stop 'nubbins' removed from the bottom triple. This is not necessary unless you choose to use the option mentioned to mount the new stops on this component.
Regardless, it could be done at home with simple tools - file alone even - but I throw this on the list in case you would like to have it done in a mill.

6. Hayabusa Fork Mod - for TL fender (Optional)
This does not need to be done on TL forks (obviously!) and only done on 'Busa if you wish to use TL fender rather than 'Busa.
It can be done at home - does not require sophisticated machining.
Tools required - hacksaw, file, 5mm (or 13/64) drill and M6 tap.
Trim the top (original) front fender mount down flush with the mounting bracket; add an M6 threaded hole per the picture above.
Note that this could still be utilized for a 'Busa fender simply by adding spacer to replace the material removed in the first step.

Once you have the parts above ready to go, the actual 'swap' project can easily be accomplished in an afternoon or plan for a leisurely weekend project.
 
#36 ·
....
There are 4 parts that do require some minimal machining work - I would estimate all four should be readily done in an hour by anyone with access to a lathe and a mill.
(can even be mini bench top tools or simply take them to a machine shop).

So take these parts for execution all at the same time - they can even be done while your Sprint is still intact (unless you utilize your original Sprint axle spacer(s) as donors) other than the time you need to remove the ignition - which can be re-installed again, even modified.

These parts and their modification:
1. Ignition Assembly
Machine 5mm off the locking pin (both pin & housing)
Elongate the mounting holes with a file to fit the TLS clamp posts.

2. TLS Top Clamp
Machine 10mm off the mounting posts
Optional - add holes for bar risers....

Let's revisit this part again:

In the process of preparing the parts for DaBrew's Sprint Hayabusa conversion, I thought I would modify the top clamp & ignition using only hand tools. If you have access to machine shop / machine tools then great! But this shows this part at least can be done with simple tools - these are extremely non-critical dimensionally.
(However don't do this for the spacers - you very much should have these done on a lathe and have a caliper gauge to validate the final dimensions)

Here are the tools I used - a vice of course is also a major asset.



Even the Dremel is a 'luxury' - the hacksaw actually makes quick work of both the ignition mounting posts on the clamp and the lock pin and barrel on the ignition. Plus a couple of files for dress-up.

Hacksaw
Bastard File
Mill File
Rat-Tail File
17/64 drill
M8 tap
Safety Glasses
Metric Rule (no precision device necessary here)
Dremel Tool (optional)

As shown earlier, the ignition posts are too long and the ignition sits low relative to the top plane.



What is required is to remove 10mm from the ignition posts. This was done simply with the hacksaw and files to dress them up & finish to same height and perpendicular surfaces.
This is a very quick operation - the aluminum does not offer much resistance to the file. Remember that you can't put it back so go easy!

That leaves the depth of the threaded a hole a little shallow, so drill it deeper then re-thread with M8 tap.

That should give you a completed modification to the top clamp assembly.
(Earlier I had drilled holes for bar-risers - this is optional step depending on what your intended bar solution might be)




Now we can move on to the ignition modifications:

The first step is simply to enlarge/offset the holes to center the ignition in the ignition ring of the clamp with the rat-tail file.
No dimensions here, just file a little and try it for size as you go until you're staisgfied with the placement.
You will have to generally enlarge the hole to take the larger M8 bolt you will use for the TL clamp. Also extend the holes slightly toward the center.
In this case you can afford to be slightly oversize, then you can adjust the ignition for center before tightening up the bolts.

 
#28 ·
thanks for the great information ! i notice that both the tl and 'busas have oem steering dampers.do you know if these were used in any of the conversions? i never felt the need for one on my RS,however if the usd forks were designed for a damper,i'd be inclined to use one. your thoughts .........
 
#29 ·
None of these conversions from first post had steering dampers.
It should not be necessary - the trail will actually be slightly longer with the shorter offset of the new triple clamps; therefor if you didn't feel need for it previously, you certainly won't after.
With my Speed Triple (approximately same geometry) I absolutely needed the damper with the OEM triumph front end - did not even bother with it after the conversion. There is no tendency to head-shake whatsoever - very stable, yet still responsive to steer.

The steering will certainly feel different - you will likely find much improved feel in cornering, that the bike will stay in the lean you put it in, without tendency to either sit up or fall in adversely.
 
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