Calliper Swaps

Caliper Swaps

It’s been noticed recently that a lot of people want to know what calipers are a straight swap to upgrade their bikes with no problems, and without having to go to the effort of making up a set of adapter plates.

So if your bike is listed in the same section as another bike below, you can change calipers without any worries.

For ease I shall just call the calipers type 1, 2, 3, 4 and 5.

Calliper swaps

Fork Tube Sizes

Fork Sizes

A lot of site users want to know about fork details, length, diameter, etc. to allow easier swapping of components between models. I’ve compiled this list forks to help you get on your way, but if there’s any missing please let me know the appropriate dimensions so that I can add them in here.

A lot of site users want to know about fork details, length, diameter, etc. to allow easier swapping of components between models. I’ve compiled this list forks to help you get on your way, but if there’s any missing please let me know the appropriate dimensions so that I can add them in here.fork tube sizes

Fitting a 916-style Steering Damper

By Banoffee.

My slabby has a lively front end, so I’ve been wanting to fit a steering damper for ages. I even acquired the period Daytona fitting kit and damper however couldn’t get that to work with my USD front end. So, seeing as I wasn’t keen on modifying the frame to take a bolt-on side mounted damper the only option left was a 916-style fitment. Seeing as I’m running an Ohlins rear shock, the damper had to be Ohlins to match of course!

Basic theory:
Whilst steering damper manufacturers don’t list fitting kits for oldskool bikes, it’s actually a simple matter of taking the measurements and then doing some research to find a suitable kit (or parts from several kits).

The measurements: (Note – some measurements are taken with internal vernier edges, some external. These are just shown to illustrate, you should of course check your own measurements carefully!)

A: Yoke nut centre to tank front mount centre

AB: Top of tank mount to top of top yoke

BC: Between centre of tank front mount bolts

CD: Between LH lock and centre (then multiplied by 2)

DThe research:
I took a tape measure with me to bike meets, bike shops etc to measure up more modern bikes (with owners permissions of course when they were about!) and also bothered a few people selling kits on ‘that auction site’.

My bike:
(750G with 400gk76a USD front end)
A: approx 50mm
B: approx 60mm
C: approx 50mm
D: approx 60mm

Things to note:
On my slabby, the damper is quite close (5-10mm) to the tank. Double, triple check all measurements to ensure it won’t foul anwwhere.
Source the fitting kit before buying a damper so that you can mock up and modify if necessary. Setting a good search on ‘that auction site’ makes this surprisingly easy and cost-effective.
For the damper stroke, obviously err on the side of slightly longer but not too long as it will look unbalanced.

The result:
I picked up a 2000-model H*nda Firebl*de Harris fitting kit from ‘that auction site’ for a whopping �20. Measurements were near-perfect as a 1-2mm on the tank mount, etc. is just fine. Only slight drawback was 30mm lower ‘B measurement’ so I acquired a 30mm tubular spacer.

EMy ‘D measurement’ (remember to multiply by 2 of course!) meant an approx 60mm stroke damper so I ordered a 63mm stroke Ohlins damper from BikeStuff (cheers Rich!).
In the pics below you can see the finished result. I’ve lost a tiny amount of right-lock, however, eventually I’ll get a spacer made up to under the tank-mount part which will solve that. All-in-all I’m well pleased!


How-to fitting 3.5 GSXR front wheel into EF front end

Capitan Chaos site moderator, motorcycle mechanic and EFE addict shares some useful info on upgrading the front wheel on your EFE.

Here’s how:

– remove the bearings from the EFE front wheel, and take the tube which is in between them. Do the same with the GSX-R one.
– you will find out the EFE one is 16mm longer than the GSX-R one. It needs shortening 16mm.
– buy some bearings which fit in the GSX-R wheel and on the EFE spindle. I don’t remember exactly the sizes, but you need bearings with the ID of the EFE ones, and the OD and width of the GSX-R ones. They were off the shelf in the local bearings shop.
– the tubes in the bottoms of the EFE forks are now too short. Make some new ones which are 8mm (each) longer.
– the EFE speedo drive will fit after a little bit of material has been removed. Offer it up on the GSX-R wheel and you’ll see exactly where.

And now, with that nice 3-spoke wheel, it would be a shame not to upgrade the brakes as well.
The Slingshot Nissin 4-pots, and the later GSX-R models’ Tokico 4- and 6-pots all fit on the EFE forks, 90mm spacing between the bolts. But the Slingshot discs are too large.
Now Suzuki had thought about this and launched the GSX600F in the late eighties, this bike has brake discs that fit perfectly on the GSX-R wheel and are small enough to accept the more modern calipers when mounted in the EFE forks. All it needs is some small rings to space out the calipers a bit towards eachother.
Use the EFE caliper mounting bolts, they are longer than the GSX-R ones.

Captain Chaos

Discuss here

Making your GSX frame stiffer

Making your GSX frame stiffer
Written by Mr.7/11, inspired on earlier work done by Tony Foale, Arnout and Tinus.

It may be well known to anybody that creating a stiff frame has to do with connecting the headstock to the swingarm pivot as direct as possible, which is what modern “Deltabox” frame designs do. So the best possible solution is to weld f*cking huge bars from the headstock directly to the swingarm pivots. There is just one problem with that… there’s a huge mother of an air-cooled engine in between that hasn’t followed any diet …ever.


To keep the weight down we remove some before adding any.

And besides she’s so beautifully shaped that we wouldn’t want anything hiding those luscious curves from full view now would we? So we’ll have to resort to beefing up the frame we have as well as possible so the front wheel will keep in line with the rear during heavy braking/acceleration as well as big bumps in the road.

The GSX frame is of the “cradle” type which means the main frame tubes are routed above and below the engine. We haven’t got many options for reinforcing the lower cradle as there are exhaust pipes, oil cooler lines and the oil sump between them and we don’t want to create problems while performing regular maintenance.
So we leave it alone with it’s primary task to keep the engine in place concentrate on the part of the frame that runs above the engine.

Take a look at the picture below.
The weak point of the frame is the green section between the headstock (yellow) and the swingarm pivot area (blue). If you look at early GSX-R frame designs you see that on race bikes they have allways tried to beef up that area with additional plates. There’s also a rumour this is what Yoshimura used to do with their GSX superbikes.  Suzuki have allready paid lots of attention into making the headstock as stiff as possible so the effect of additional bracing here will be minimal. If you intend too keep the standard airbox and the battery in it’s original place then options for bracing around the swingarm pivot will be minimal too. So if you would like ot improve the stiffness of your old dinosaur I’d make modification C. first, and consider dumping the airbox in favor of separate K&N filters to be able to add D. and E. When you’re at it you might as well go along and add braces A. and B. but I don’t consider them to be essential.

Be warned that reinforcement C. can hit the inside of the tank if you make it too big and will also make it hard to find enough space for the air filters! You should make all reinforcements from cardboard first anyway to check that they don’t interfere with anything.


A. these tubes support the headstock against torsional movement. The plates B. support the frame tubes to prevent them from bending due to the load created by tubes A.

The cross-bars D. stiffen the area above the swingarm pivots. The tube connecting both sided is placed at the same height as the engine mounts to keep the engine in place under acceleration. If we replace the cross-bars with a pyramid D1. we add even more stiffness to that area and prevent the swingarm pivots from moving back and forth in addition to up and down. It may look a bit awkward and I question if it adds anything as you must not underestimate the strength and function of the rear subframe.
This might be why Yoshimura adds gussets to the subframe on the Katana 1135R, but they have also changed position of the shock mounts considerably. They probably did this because they use a very short swingarm to decrease the wheelbase and so improve steering into corners and if they kept the original mounting point the shock would be too upright making them too hard.


Examples of frame braces on the Yoshimura Katana 1135R

The connecting rectangular tubes E. help to distribute loads from the swingarm pivots to the rear of the frame, as well as providing a mounting point for the rear brake amongst other things.

F. There’s very little room to triangulate the space in front of the cylinders because of the exhaust pipes but it is possible. You may need to dent the tubes a little to make them clear the exhaust pipes but this is better than making the V smaller. Tightening the two center exhaust clamps will prove difficult too.

Gussets © Tony Foale

Gussets © Tony Foale

Now that the headstock and swingarm pivot areas are beefed up the connecting tubes are supported by plates C.

You should also consider making B. and C. box sections, so placing a plate on both sides of the tube with a strip in between to close the box. Or use rectangular box-sextion like I did (60×20)

Tubes only need to be around 16mm in diameter with a 1mm wall thickness. Box sections need to have 1mm wall thickness and single gussets 3mm.

Below are images of a braced GSX1100S Katana frame.
The bracing is designed by Mr.7/11and welded by Postma Motoren from Haarlem (NL)

Usually I don't get horny from stiff objects but this is a completely different matter...

Usually I don’t get horny from stiff objects but this is a completely different matter…

You can allmost feel the flow of the forces trough the frame tubes

You can allmost feel the flow of the forces trough the frame tubes

The big cross means "no airboxes allowed" and will probably be painted red

The big cross means “no airboxes allowed” and will probably be painted red

The use of rectangular beams in the subframe means it's easier to bolt stuff onto it like electronics, brake pumps, nitrous solenoids etc.

The use of rectangular beams in the subframe means it’s easier to bolt stuff onto it like electronics, brake pumps, nitrous solenoids etc.

GSX-R engine mounts for GSX frames

Below are drawings of engine mounts to fit an early air-cooled GSX (round frame tubes) or EFE (square frame tubes) with a GSX-R engine. Both place the engine in the middle which is aesthetically best but may cause some problems with the exhaust headers interfering with the frame downtubes, which can be solved by using spacers or modifying the headers if necessary.
Engine mountsEnginemounts1 for a GSX1100 frame to take a GSX-R engine.
By “jonboy”




A Katana with the above engine mounts installed…









Engine mounts for a GSX1100EFE (GS1150) to take a GSX-R engine.
By “GJG”

Below are drawings from the engine mounts, as I used them a few years back. I built at least two EFE’s using these plates. They mount the engine pretty straightforward, like in the Katana I send you pics from a few months back. I also included the cutting contours in .dxf format, that could straight be fed into a laser.

Parts description:
PL-105 and 106: Take front rubber engine mount, and lower below crank. Need shims or bushes to compensate for offset.

PL-107 and 108: These should be welded in with the engine or cases in place, mounted with the previous mentioned plates. PL-108 is a bit long, and could do with a brace, taking sideward loads to the cross tube from the shock. The stock plate should be removed. The lower cross tube in the frame will need some cleaning up and removing of the stock lower rear plates, before taking PL-107.

PL-110 and 111: These make the removable, welded upper rear engine mount taking loads to the stock bolt holes/bushings welded into the side of the frame.

GSX1100 Laser drawings