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RZ350 FZ600 SWINGARM/FZR WHEEL CONVERSION

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   ATTENTION!:  There once was an RZ owner named Stace Scoggins. He had posted his FZ600 swingarm/FZR Wheel conversion on a site called 2stroke.cc. Since then 2stroke.cc has folded and the conversion was lost. Attention: this page is not exactly like the authors original creation. I think there are a few pictures missing at the end and the text is misaligned in several places. I did almost the best I could just cutting and pasting text. To only be used as reference material and not a 100% guide to these modifications.

FZ swingarm conversion with FZR 18 x 4  rear wheel

 

DISCLAIMER:  I take absolutely no responsibility for whatever you do in the comfort of your garage.  I had no control over Yamaha’s manufacturing tolerances when these bikes were manufactured and therefore what may have worked on my bike, may be too big or too small for your bike.  Please recheck all measurements and all fitments. Modifying the suspension can have adverse effects on the handling of your motorcycle and by doing so you assume all risk involved in these modifications.   Remember that motorcycling is an inherently dangerous sport and can result in serious injury and even death.  It is your responsibility to make sure that your bike is roadworthy and safe.

 

This is a proven conversion that has been done by numerous RZ owners.  It keeps the same wheelbase as stock and allows you to run up to a 150/60 tire.  The downside is that the rim is an 18 inch rim and the tire selection is not as great for an 18 inch rim as for the 17 inch rims.  Hopefully this write up will give you a good foundation and serve as a good basis for your conversion.  I have done this conversion about 4 times and had success each and every time but I did not take these measurements as the gospel – I only used them as a guideline as each bike has it’s own nuances.

 

 

Parts needed:

FZ swingarm  (46X-22110-01-00)

FZ swingarm pivot point dust covers (47X-22129-00-00)

FZ shock linkage (Left 46X-2217M-03-00 Right 46X-2217N-03-00)

FZ axle and nut

FZ chain adjusters

FZ or FZR brake caliper mount

FZ or FZR brake torque arm

FZ or FZR brake line stay (46X-25876-51-00)

FZ Chain slider (46X-22151-01-00)

FZR rear brake caliper

FZR rear rotor

FZR 18" x 4" wheel

FZR sprocket carrier/cush drive

FZR cush drive rubbers

FZR wheel spacer (sprocket side)

NEW swingarm bearings

520 rear sprocket to fit the FZR sprocket carrier

 

Reuse from RZ:

          RZ Pivot tube

          RZ Pivot bolt and nut

          RZ relay arm (from frame to shock)

          RZ shock  (see recommendations below)

          RZ brake line

 

Highly recommended:

          FOX shock with ride height adjustment

NEW FZR wheel bearings and sprocket carrier bearings (See Appendix)

NEW 520 chain

 

STEP 1:  Narrow the swingarm

Remove your RZ swingarm and either take the measurement of the RZ pivot point OR remove the RZ pivot point tube – this will give you the width that you need the FZ swingarm narrowed to. 

image1.jpg

FZ pivot tube (bottom) vs. RZ pivot tube (top)

 

You must remove  the swingarm needle bearings

before machining. You need a long drift to knock these out

(a drift is a long piece of rod – I typically use brass as

it is soft enough to not do too much damage) or you

can pay your machinist to do it.  Plan on buying new

bearings however, because pounding them out

basically ruins them.  You must also remove the hard

plastic bushings and seal for the shock linkages

(I used a socket the same size as the face to knock

these bushings out.  I then took the bare FZ swingarm,

the RZ pivot tube, and a dust seal to my machinist

and told him to narrow the FZ swingarm to the width

of the RZ pivot tube and to machine the area for the

FZ dust seal. (see pictures below)

image2.jpg

FZ pivot tube (bottom), RZ pivot tube (middle) and narrowed swingarm.

image3.jpg

Nice view of narrowed swingarm with the dust seal area machined.

 

 While the arm was at the machinist, I had him TIG weld some lugs on the underside of the arm for race stand spools using 5/16 diameter 6064 aluminum rod.  He drilled and tapped the rod for an 8 mm bolt that is used to secure the spools (see picture below).

image4.jpg

Mounting lugs for race stand spools.  Make note of the weld on the inside of the swingarm leg, we will discuss this in a later section.

 

 

 

 

STEP 2:  Making space for the wheel

NOTE:  What follows are notes from my conversion process using the FZR 18” x 4” wheel.  These specs may work for the 18” x 3.5” inch wheel, but I do not have direct experience with it – also stay tuned, I am searching for an 1988/89 GSXR 17” x 4.5” wheel that I have been told works in the FZ swingarm.  No matter, which wheel you chose,  I think the largest tire that will fit in the FZ swingarm is a 150/60 – any wider and the tire will hit either the swingarm, the chain, or the brake torque arm.

 

The goal is to center the FZR wheel in the FZ swingarm, do not worry about chain alignment at this point – this will be covered later.  If you do not center the wheel, then the tire may hit either the brake torque arm or the chain, plus you handling may be affected.  To get the FZR wheel to fit, you have to remove equal amounts of material from the wheel spacer on the sprocket side and the rear brake caliper mount (you can use the FZ or the FZR – they are the same).  The wheel spacer is hardened steel and can not be easily milled.  The stock width is 14 mm.  My machinist actually had to grind it down to a width of 9 mm.  So we removed 5 mm from this side.

image5.jpg

Stock spacer on left, machined spacer on the right.

 

The stock width of the rear brake caliper mount is 27 mm.  I had the machinist mill the arm down to 19 mm and then I use  a 3 mm thick washer during assembly to add back 3 mm (total width with washer and milled arm is 22 mm).  The reason for the washer is to account for the lip on the stock brake arm that keeps the sides of the arm from rubbing the swingarm.  Using the washer is MUCH cheaper than having the machinist machine the lip plus it gives you some room for adjustment.

image6.jpg

Note the lip at the end of the file – Stock brake caliper mounting

bracket  on left, machined bracket on the right.

image7.jpg

3mm washer used as a substitute for the lip or the expense to have one machined.

image8.jpg

image9.jpg

Machined sprocket carrier on the left, stock on the

right – notice the

black rim on the machined carrier – that was the

sprocket mounting

area  before machining.

 

 

STEP 4:  Address the details

Below is a list of little items that will come up during the

install,  you can handle these as you see fit but

remember the details need to be addressed and

focused on, usually the slightest thing will be the thing

that causes the most catastrophic results. 

 

Ride Height

If you utilize the FZ linkage (from swingarm to

shock) and a FOX shock with the height

adjustment at it’s max, then you should be at

about the same level as stock.  DO NOT use the

RZ linkage unless you shorten it considerable,

your bike will be too low.  Since I weigh in at

around 240 pounds, I knew I needed an

aftermarket shock – no doubt about it.  I also did

not feel comfortable cutting  and welding the

linkage to make it shorter. 

Just think of the tragic scenario that follows if the

 

linkage

breaks. 

 

Shock Linkage mounted Chain slider/guide

On the stock RZ (at least on my 86) there is a hard

white plastic chain slider bolted to the relay arm on

the chain side (of course!!).  The micro-fiche calls

it

a chain guide and this is item 33 on the swing arm

micro-fiche for 84/85 US models and item 32 on the

86 micro-fiche.  There is not provision for this on the

FZ linkage.  I had my machinist drill and tap the linkage

for the stock 6 mm bolt.   The FZ relay arms are a bit

 

wider than the RZs so out came the Dremel tool to open

up the mating surface in the plastic slider.  This plastic

slider basically acts as the lower limit for chain travel

– the chain rides between it and the underside of the

swingarm and in my case kept the chain from rubbing

the bulge in the expansion chamber (which is a good

thing!!)

 

I recently bought a roller that is used on dirt bikes for the

same purpose as our stationary plastic slider.  It basically

looks like a small skateboard wheel and it has a sealed

bearing and would roll with the movement of the chain

rather than being stationary like the stock white plastic

piece offering less resistance and probably less wear

on the chain.  The only issue is that this one had an 8

mm bolt and the stock in the linkage was 6 mm.

image10.jpg

Arm of FZ before contracting, with polished half.
Notice the mallet in top on the right. One always needs
a mallet.

Initial assembly:

OEM White chain guide next to the new roller

Not really wanting to enlarge the hole in my linkage to 8 mm(so I could go back to stock if I wanted), I went to the local ACE hardware and found some shouldered plastic sleeves that allowed me to use the stock 6 mm bolt size.

I went home and bolted the roller up with a nut between the roller and the linkage for proper spacing. Put the bike on the stand and spin the rear wheel - man is it much quieter now!! I can not believe the difference. Clearance is close between the LOMAS GP pipes and the roller when the bike is unweighted due to the curve of the left pipe, but once I sit on it, the suspension sag gives plenty of clearance. If you are running stock exhausts or expansion chambers with one on either side of the swingarm, you will not have any issue.

Better shot of the roller

Rear Brake Line

I think I ended up using the stock RZ brake line after ruining the FZR brake line.  The FZR rear brake line is way too long.  I thought I had it zip tied away from the wheel/tire, but I let a buddy of mine ride it and he came back and stated that there was no rear brake.  Glad he found it as I hardly ever use the rear brake.  Evidently, the zip tie had broken and the FZR line had rubbed on the tire and wore a hole in the line.  SO the moral of the story is to watch your routing and make sure the line is secure and out of harms way!!

 

Rider Footpeg Bracket to Swingarm Clearance

You should check that your foot peg bracket and the expansion chamber mounting point to the foot peg bracket clear the swingarm.   I had to move mine out a bit.  You can either add spacers behind the bolts where the footpeg bracket bolts to the frame, or you can just grab the brackets and yank outward while a friend holds the bike.  Depending on your size, this may or may not be easy.  Also be aware that the lugs that the brackets bolt to are relatively thin metal and may break.  I took the risk and moved my bracket out a couple of millimeters on both sides – I would rather do this than have the expansion chamber bolts gouge the soft aluminum.  I also used round head allen bolts with the head to the inside for when mounting the expansion chambers.

 

Chain Guard

I tossed mine and do not use one.  Clearance between the chain and the tire do not allow for one – I may build a custom one out of aluminum at some point.

 

 

STEP 5:  Mounting up the goods

Okay so now you have a narrowed swingarm, new swingarm bearings, machined wheel spacer, machined brake caliper mount, and either an offset countershaft sprocket or a machined sprocket carrier along with all the other associated stuff. 

 

First you must put the swingarm bearings and the plastic shock linkage bushing in the swingarm.  DO NOT pound these in – you may get lucky and they will go in fine, but more than likely the pressure from pounding will ruin the bearings/bushings at best and at worst you could damage the swingarm (that would be a shame after all that work and expense).  To install bearings, I use a section of ½ inch AllThread  (a long threaded rod) with two big washers and two nuts.  First I packed the bearings with grease and then place them in the freezer (don’t let the wife catch you) - this makes the bearing shrink ever so slightly.  After about 30 minutes, I take the bearings out of the freezer and get them started in place after lubing the bearing mating surface  – MAKE SURE THEY ARE STRAIGHT!  Put the AllThread through the bearing and put a washer and nut on one side – put the washer and nut on the other side and start tightening one nut as you hold the other with a wrench.  The bearing slowly moves into place.  I typically do only one bearing at a time to ensure that everything goes in straight.   This works for the swingarm bearings and the linkage bushings as well as wheel bearings.  Go slow and make sure they are straight and you will have nicely installed bearings that are not damaged from pounding them in. 

After the bearings/bushings are installed, grease the pivot point tube and put it in place.  Next install the dust caps and do not forget the washers that are inside the dust caps!!  Put the swingarm in the frame without the shock (it’s easier this way!) and tighten up the pivot point bolt to factory specs (actually you can follow your manual from this point on for reassembly of the swingarm/rear wheel – you DO have a factory manual don’t you??).  Make sure you check the side to side play and follow the manual if you need to adjust.   Install the shock and the appropriate linkage. 

 

At this point, install the wheel and the rear brake caliper (don’t forget to bleed the rear brake if you opened the system!!)  I really like the looks of the FZ brake torque arm and it is aluminum as opposed to the steel FZR torque arm, but it appears that the FZR arm is about 2 mm narrower so I have been using the FZR steel one for the extra clearance to the tire.  Finally, put your chain on and adjust the tension and alignment. 

 

Double check everything twice – fasteners, chain alignment and tension. Bounce up and down on the suspension to make sure there is nothing contacting anything else.  When you are comfortable that everything fits and is tightened – do it again!!  Let the thought of the rear wheel locking up at any speed and the damage that would do to your machine and you and this is in a straight line.  Now think about that same scenario but this time as you are scraping you pegs or your knee in a corner. 

 

As stated earlier, I have done this conversion about 4 times and had success each and every time but I did not take these measurements as the gospel – I only used them as a guideline.

image11.jpg

Brake
                                    system

Notice the brake system of FZR, too long and to replace
possibly by that of the RD

image12.jpg

APPENDIX A:  Wheel Bearings

 

Supplier:     World Wide Bearings     

                                      1-800-575-322

                   Worldbrg@aol.com

                   Dave is a good guy and can help you with any of your bearing needs.

 

FZR front wheel bearings

Part number:

Size:

          Quantity needed:   2

 

 

FZR rear wheel bearings

          Part number:

Size:

          Quantity needed:   1  (brake rotor side)

 

Part Number: 

          Size:

          Quantity needed:   2  (sprocket carrier side)

 

 

FZR sprocket carrier bearing

Part number:

Size:

          Quantity needed:   1

 

RZ/FZ swing arm needle bearings

          Part number:

          Size:

          Quantity needed:   2

                  

image13.jpg

Pictures Courtesy of Stace Scoggins