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Sorry about that, folks ... got to be done these days, unfortunately.
R1 Fork Installation
This mod is a pretty common one now but having run K-tech modified OE forks since 2003, I figured it was about time to give the R1 option a try on my 2002 Fazer. For the benefit of anyone considering doing the same here’s a few words and photos that might help you along the way.
Why Do It?
Two reasons; first, appearance - USD forks look better and more modern, plus they lower and shorten the bike giving it a sportier, more aggressive stance. Second, performance - depending on the type of R1 forks and yokes you use the lowered front and shorter wheelbase makes a noticeable difference to how the bike steers. There’s more weight on the front wheel, it turns in quicker and yet remains 100% stable when leaned over or at high speed in a straight line.
Which R1 Forks to Fit?
Any year/model of R1 forks can be made to fit the Fazer but the later ones involve more outlay on compatible front wheels, brakes etc. In each case the R1 mudguard is required as the Fazer one doesn’t fit.
The original 98/99 4XV forks are 40mm shorter than the Fazer forks and have 135mm of travel which is 5mm less than the Fazer. The Fazer front wheel, axle and brake discs fit without any mods. The R1 fork tubes are 41mm in diameter.
The 00/01 5JJ forks are externally the same as the 4XV but have improved internals.
The 02/03 5PW
forks are about 45mm shorter than the Fazer forks. The Fazer front wheel and brakes still fit
without mods but require the 5PW axle.
The fork tubes are now 43mm in diameter.
From 04 onwards the R1 fork tubes remained at 43mm in diameter, gained radial brakes and wheel travel reduced to 120mm. To fit the later model R1 forks requires the complete R1 front end, comprising wheel, discs, mudguard, radial brake calipers and master cylinder.
No matter which year R1 forks you choose, you have to decide which yokes to use with them. In all cases the yokes require a Fazer steering stem to ensure the bearing cups and races match the dimensions of the Fazer steering head.
If money’s not a factor, you can get a full set of custom yokes made up hold the R1 forks lower down to compensate for the shorter length. The full custom set also lets you decide the amount of fork offset you want to use. Alternatively, you can pair a custom top yoke with an R1 bottom yoke to lower the forks. This is a little less expensive but the offset is now determined by the R1 lower yoke.
The cheapest solution - and the one I chose - is to use both R1 yokes with the Fazer steering stem pressed in and a few other minor mods. This lowers the front of the bike but not by as much as the actual difference in fork leg length. Because the R1 yokes have less offset than the Fazer yokes the fork legs and front wheel are closer to the steering head.
In practice, with the shorter 5PW forks and yokes, the front of my Fazer is about 35mm lower than standard. I reckon the height of the rider’s seat has reduced by 15mm or thereabouts. Although the front wheel/mudguard look close to the radiator there’s no clearance issues even on full fork compression.
If you’re bothered about the front ride height, it’s worth noting that the 5PW yokes have about 8mm less offset than the earlier model R1 yokes (ie, they bring the fork legs 8mm closer to the steering head). I reckon a pair of the longer 4XV/5JJ fork legs paired with the 5PW yokes would raise the front a few mm higher than the same fork legs fitted in their original yokes.
The photo above shows the 5PW (top) and 5JJ (middle) alongside the Fazer forks.
From here on all the mods referenced apply to the 5PW forks/yokes on my Fazer. I also modified a set of 5JJ forks and yokes at the same time which is why you’ll see some photos of those here. The work involved is identical.
If you get a spare Fazer lower yoke you can get all the mod work done on the R1 forks before you strip down the bike. It will add a bit more to the start-up cost but you’ll have the original to keep or sell on when the job’s complete. Ideally you should be able to simply remove the Fazer forks and bolt on the complete R1 front end as a one-for-one replacement.
following work can be contracted out to an engineering shop if you don't have much by way of a workshop. I had mine done by a guy here in Spain because I believed at that time it was necessary to use an hydraulic press to remove the steering stems from each set of lower yokes. I've subsequently learned that it can be done with simple hand tools and a vise. See post #116 for more details.
Steering Stem Swap
Whatever you choose to do about the top yoke, the steering stem from the R1 lower yoke must be removed and replaced with a Fazer steering stem. The R1 stem is wider and much shorter than the Fazer’s and won’t fit into the Fazer steering head.
It’s important to get the Fazer stem inserted and fixed in the R1 yoke to the correct depth in order to maintain the proper spacing between lower and upper bearings. Installed in the original yoke, the Fazer stem measures 251mm from the upper surface of the lower yoke to the top of the stem.
shows the Fazer stem in the Fazer yoke with the R1 stem alongside for
comparison. Note the lower bearing race
on the Fazer stem where it butts against the yoke. Use this measurement to confirm the Fazer stem is pressed into the R1 yoke to the correct depth. Another check is that when fitted to the R1 yoke, the Fazer stem
protrudes 7mm beneath but it’s not noticeable on the bike. Note that the R1 stem
has a retaining circlip that fits in a groove at the bottom end so the stem must be pressed/drifted out from the top downwards. I am also led to believe that the steering stems are slightly tapered, so if they're pressed out from the bottom upwards there's a danger of enlarging the stem hole in the R1 lower yoke.
Top Yoke Spacer & Insert
stem hole in the R1 top yoke is wider than the Fazer’s so you need an insert
pressing in to reduce the internal diameter to 23.4mm. The external diameter of the insert is 27.85mm and it needs to be 12mm deep. This photo shows the yoke
with the insert fitted.
The R1 top yoke is thinner than the Fazer’s so a spacer is essential to raise the yoke high enough to allow the steering stem top nut to be torqued down.
Without the spacer, the thread ends just a fraction less than 11mm above the yoke as shown here.
With the spacer, the thread sits below the yoke like this.
The simplest spacer would be like a large flat washer, 41mm external diameter (to fit the recess in the underside of the yoke), 23.4mm internal diameter to fit over the steering stem and 11mm thick to raise the yoke the required amount.
Alternatively, the stem insert and spacer could be turned as one piece. It would look something like an inverted top hat with a hole through the centre. The dimensions below worked for me but I urge you to double-check them against the parts you’re modifying, just in case.
A more complex but neater solution is to press a separate stem insert into the yoke and have an alloy spacer/shroud turned up to raise the top yoke by the required amount and cover the steering bearing locknuts. This is the route I chose and I think it looks neater this way.
dimensions of the spacer/shroud are shown in this diagram.
The shroud section completely covers the steering bearing adjuster nuts as you can see here. The shroud section which you see here isn't load bearing so 1.5mm thickness is more than adequate.
In case you’re wondering, it’s not possible to compensate for the thinner top yoke by having the steering stem pressed further through the lower yoke because this would prevent the steering head bearings fitting together correctly.
The spacer you need are available from forum member Justy and you can find details here:
The completed yoke set with spacers looks like this. There’s a spare spacer/shroud on the bench for illustration.
ENGINEERING SHOP OR DIY WORK
I did the following mods myself with basic workshop tools but as before, you might want to give this work to the engineering shop if you lack the necessary facilities or skills.
Lock Stop Reduction
The lock stops on the R1 lower yoke must be ground down by 6 mm to give acceptable turn radius. I used a Dremel and cutting wheel plus a file on mine, checking the amount of lock vs frame clearance as I went along. On full lock, the fork legs on mine are about 20mm away from the top frame rails and the turning radius is fine - a bit less than the original forks but not by much.
This photo shows the modified lockstops against the frame stop. Don’t remove more than 6mm because the point of contact would be reduced to an unsafe amount.
shows the cut-down lock stops on the 5JJ yokes.
Note also the simple flat alloy bracket I fabricated to hold the 3-line
brake hose splitter union. The splitter bolts up through the centre and right bolts, the left hand bolt holds that end of the bracket to the yoke.
The Fazer ignition switch will fit in the R1 yokes with a little modification. Grind off the heads of the security bolts holding the switch to the Fazer top yoke. Remove the switch and enlarge the bolt holes by 1mm. This is necessary because the bolt centres are slightly wider spaced on the R1 yoke. You will also need a couple of 12mm spacers (shown in the photo below) to hold the switch at the correct height in yoke when you bolt it in place. You will need two M8 x 40mm socket heads or similar. It might also be necessary to relieve the web between the bolt holes to get the switch to fit straight and neat at the correct height.
The steering security lock operated by the ignition switch, that is. I never used mine on the Fazer so didn’t bother to engineer the switch location to retain this function with the R1 forks. It might be possible - try it and see for yourself.
The R1 yokes have two holes in them for M6 bolts that secure the clip-on bars. Enlarge these holes to accept the studs on the Fazer bar clamps. I shortened the studs on my Fazer bar clamps and extended the existing thread with a die so that they’d fit neat and bolt up securely beneath the yoke without the need for spacers.
Depending on which model R1 yokes you use, it might be necessary to reinforce the bolt holes with weld when they’re enlarged.
The 4XV yokes should be OK without but the 5PW yokes are of a lighter construction so I had alloy bosses welded in to strengthen them under the bar clamps.
Steering Head Bearings
You can re-use the Fazer bearing races and caged ball bearings if they’re in good condition, or you could use this opportunity to replace the ball bearings with tapered roller bearings.
The original 3-line Fazer brake hoses will fit but they’ll be a bit on the long side. As mentioned previously, you’ll need to fabricate a bracket to enable the splitter union in the mid-section of the hose run to be bolted to the lower yoke.
A neater solution is to replace the 3-line system with a 2-line braided hose set-up. I got a custom-made set from Venhill comprising one 730mm hose and one 755mm hose with 2 x straight unions for the calipers, with one straight union and one 20 deg offset union for the master cylinder connection.
NEW FOR OLD - THE CHANGEOVER
You should now have a completely modified set of R1 forks and yokes similar to these ready to fit to your Fazer.
I’m going to assume that you have a Haynes or Clymer manual to guide you through the removal of the Fazer forks and yokes. Slotting the R1 set into place is straightforward reversal of the dismantling process.
A few tips to go with the Haynes/Clymer directions. You can get at the forks and yokes with the fairing in place but I recommend you remove the screen to ease access from above. Also, remove the fuel tank - it gives you more room to work and you’ll want to lay the handlebars on the frame rails when you take them out of the clamps. Put an old towel over the frame and top of the engine to prevent anything dropping onto the engine or marking the frame rails.
Pay close attention to the control cable, brake hose and wiring loom routing in and around the steering stem and fork legs. Take photos to remind you where stuff goes in case you you’re not sure come rebuild time.
Loosen all the major fasteners a fraction while the front end is complete and securely on the ground. Heaving at the steering top nut with the front wheel out and the bike balanced on the rear wheel and a prop stand isn’t such a good idea.
When the rebuild is complete, measure and adjust the fork preload to give 10 - 15mm of static sag (no rider). Set the damping adjusters to the middle settings and bounce the forks to see how they feel. Make any adjustments you feel appropriate at this stage, then go test ride and fine tune thereafter.
Finally, a word about spring rates. The standard R1 fork springs may be a bit soft for the Fazer as there’s a difference of 30kgs in dry weight between the two bikes. Before fitting the R1 forks to the Fazer it’s worth taking specialist advice about the spring rate. It might be a good move to fit firmer linear rate springs before you install the forks. Assuming you’ve sourced the R1 forks from a breaker or ebay, it would be sensible to do a fork oil change anyway, so swapping the springs at the same time - if you need to - would make sense.
The Finished Result
This is what you’re aiming for - or something similar. I like it and think it was time and money well spent.
Addendum 11 Feb 2010
FZ1OA forum member tqmx1 has found that a Gen 2 Fazer top yoke has exactly the same offset as the R1 5PW lower yokes. With the appropriate spacers it's therefore possible to use this combination to fit R1 forks to the Gen 1 Fazer. The main advantage is that the Gen 2 yokes are sturdier and already have bar clamp holes. Photos and more information on this variation here. My thanks to Kim for his permission to post the link and for sharing his discovery.