/> />

Using a 3TJ swing arm with a 3HE axle & wheel

or

3TJ axle & 3TJ wheel with a 1WG sprocket carrier

BUT

both using the 3HE swing arm bolt

plus

Using a gsxr 600 rear shock as well

 

 

I must clarify why I have chosen such a convoluted modification. The previous swing arm mod which is documented elsewhere 3EN swing arm mod turned out to have a number of significant GOTCHA's.

Whilst they could be worked round quite easily if you used the original shock or one of a similar style, the swing arm bracing fouled on any modern shock reservoir. Since the original plan was to replace the original shock, the 3EN swing arm was not for me.

a footnote here is in order:-
The 3EN swing arm and caliper linkage do provide a SUPERIOR ride over the original rear end



3tj swing arm top

Starting with a look of the 3TJ Swing Arm from the Underside.



3tj swingarm side

A look at the 3TJ swing arm from the Right

As you can see it is a very beefy built swing arm.The swing Arm pivot bolt (the one that holds it in the frame) is 20mm diameter where the 3HE swing arm & frame take a 15mm bolt. It therefore requires that a sleeve be fitted inside the original pivot bolt sleeve of the 3TJ to further reduce the 20mm down to 15mm diameter.

3tj modded bush

The new inner sleeve inserted & tack welded to the 3tj original inner sleeve



3he bolt in 3tj mod bush

With the new inner sleeve in place the 3he bolt is a precision fit


 

So the 3TJ swing arm will slide right into the '92 FZR600 3HE model frame now without any further modification

Ok so now comes the trickier deal I have a 3HE 18" diameter * 4.0 wheel with a brand new tyre on it (the original blew out the day before 3TJ swing arm was due to be fitted and the 17" * 4.5 rim arrived ) I also now have a 17" rim etc.

OK, I decided that I would put the new tyre to work BUT all modifications to fit the 3he wheel must be temporary so the 17" wheel could be fitted at a later date

The problems are:-

1} The 3TJ axle is 20mm in diameter

2} axle slots in the swingarm are therefore 20mm wide

3} 3he axle is 17mm diameter

4} 3he 18" wheel has 17mm bearings & 20mm cannot be swapped in !!



To fit the 18" wheel & 17mm axle

Ok so lets take the problems in order the 3TJ swing arm requires a 20mm axle which cannot be fitted to a 3HE wheel since there are no readily available bearings with the correct outer diam and 20mm bore.

It therefor requires the 3HE 17 mm axle to be used and the 3tj swing arm be spacered out. Since the axle pullers are 20mm also, it is therefor simple to make a spacer that is a push fit into the axle puller but wide enough to fit the width of the swing arms axle slot.

These can be seen in the two pictures below:-

3he axle in 3tj arm 1



3he axle in 3tj arm 2

Since the caliper bracket will be used on both wheels at some point, I decided to bore out the bracket to 24mm and then double sleeve it. This has two purposes :-

A} allows the sleeve to be used as a spacer addition since the 3TJ swing arm is wider at the axle by 8 MM overall, so the sleeve is made 4mm wider than the caliper bracket but has a bore of 20mm that is additionally sleeved down to 17mm.

B} allows the spacer part to remain when the final conversion is done to 3TJ wheel and axle.

The last part of the conversion is to add 4mm to the sprocket side spacer so that the wheel is centralised and the chain run in a straight line

wheel alignment

The right hand rider foot peg bracket clears the swing arm easily but the slip on exhaust does NOT clear the swing arm entirely and will need awasher inserted between the can holder and the passenger footpeg bracket.

The leftside rider peg bracket is the real hassle, as you will see it required some very skillfull grinding to rear face of the bracket to match the curve of the 3TJ swing arm to enable it to be fitted.

lh peg close up

Well that is 18" wheel fitted in the 3TJ arm, the saga continues

Using a 17" 3TJ wheel & axle + 1WG sprocket carrier in the 3TJ arm

 

Put like that it sounds oh so simple, but like all things that look or sound simple they rarely are !!!!

Ok so the bike is a FZR600 3HE 92 model and it has been fitted with a 3TJ (fzr400) alloy swing arm BUT still using the 17mm pivot bolt from the 3HE to hold the swing arm & the old 18" wheel for which good modern rubber si not redily available.

In the interest of getting sexier compounds for the tyres I decided to go with a 17" * 4.5 rim from the 3TJ which came with the rear disc but no sprocket carrier( Ebay sellers ??? ). I waited 6 months no sprocket carrier so i asked around and came up with thw 1WG model which was alledged to fit.

Alas like all things "well it should fit" it was almost a fit. the outer diameter was good & the cush drive fitted (3he is way too big and different cush drive fit entirely), the hassle was the 3TJ has a20mm axle and the 1WG has a 17mm axle so the cush drive bearing is too small or so it seemed. On closer inspection the bearing has a 20mm bore but has sleeved spacer internally that reduces the bearing bore.

By pushing out the spacer/sleeve the bearing is good to go.But as always there is a GOTCHA, the cush drive needs to be spaced off the wheel bearing. so the larger diameter of Yamaha's spacer/sleeve has to be duplicated and used between the wheels bearing and the sprocket carrier / cush drive bearing so the wheel & carrier do not rub on each other.

wheel axle with sprocket

The 1wg Sprocket carrier on the 3TJ axle with the new spacer and the 3TJ wheel with cush drive in place.


To fit this new 17" wheel in the 3tJ swing arm it now only remains to remove the axle puller sleeves that were installed for the 3HE 17mm axle, together with the inner sleeve of the caliper bracket (leaving the 4mm spacer part in place) and fit the new wheel axle assembly as normal.

A foot note:- 3HE sprockets fit directly on the 1WG sprocket carrier no mods AMEN.
Using the GSXR 600 rear shock with all of the above

The GSXR 600 rear shock is just like the FZR shock in that it has a forked lower fixing (unlike R1's etc) but has a 50% stiffer spring rate and after market spring replacements if that is still too soft for your taste.

It is gas/oil controlled & has the usual preload adjustment which is not the usuall 6 or so settings but is infinitely variable. (you do need the special "c" spanner for this and some good arm muscles ). To match this it has rebound damping and compression adjustments both of which have clickable settings for easy memo taking when trying out your new ride (you do take notes don't you?)

The Gsxr shock will work with the 3HE fzr600 / 1wg FZR400 / 3TJ FZR400 BUT NOT THE 3EN model FZR 400 or any other FZR with a braced swing arm (FZR1000's) as the gas resevoir will foul on the arm's bracing.

Ok so what is likely as a GOTCHA:-

A} The shock is 0.5" longer

B} The top bushing is only 10mm diam NOT 12mm as on the FZR

C} the top bush is 10mm narrower than the FZR

To keep the ride height correct and compensate for the shocks extra length you need new "dog bones" (shock linkages) that have the mounting holes @ 138mm centers.

You will also need stepped bushes(2 pieces) that will have a 5mm thick 17 mm diam section with a further section 12mm diam (bushing section to fit inside the FZR frame shock mount) that is 10mm long and the thro hole is 10mm.

You will also need a 10mm diam bolt to replace the 12 mm diam FZR version


shock top with bushes

It is worth noting that the bushes in the picture are reversed the big diameter is supposed to be against the shock head. This will then allow the bushes to slide into the frame bracket holes !!

shock top in place

Gsxr shock top in place

shock bottom on trilobe

Gsxr shock bottom inplace on the 3HE trilobe

Battery box + shock

Gsxr shock when it is all put together and just how tight it all is



Well I hope that helped you out some I can be found here or on the
Online FZR community

For further details E-Mail:- KGB-Racing at Saltmine dot Org dot UK

Get Adobe Reader Join the Blue Ribbon Online Free Speech Campaign
3D Animated Flags by 3DFlags.com

Back to:- Project FZR


This Page Sponsored by The Saltmine Org. UK
 UK flag animation  ©  Geo of K.G.B. of T & T.   UK flag animation