02 June 2012

FZ1 Mod: R1 Fork Conversion Revisited

Lower Triple Do Over.
Back in January I had my front wheels bearings replaced because I noticed a little wiggle with the front tire.  It turns out it wasn't the wheel bearings but loose steering.  It seems you shake the wheel to test the wheel bearings and the forks for the steering bearings.  I shook the wheel it shook but I didn't bother to shake the forks.  During my last trip, the steering loosened up so much I could no longer deny that there might be something else wrong.

I took the bike back to OTC as soon as I could and discovered that I was missing the collar that goes over the neck.  That might have been the reason for the loose steering so the part was ordered.  Once it arrived, OTC discovered that wasn't the reason for the looseness.  When we made the decision to have the stem pressed into the lower tree so that it was flush, we didn't take into account the extra 7mm that Falcon mentioned his guide.  When the front end was first installed everything was tight so we didn't think there was a problem.

During this process I learned that sometimes tapered bearings "seat" better after riding the bike a bit.  This is what happened with mine and since the stem was pressed flush to the bottom of the lower triple it changed the dimensions between the upper and lower bearings resulting in loose fitting.  The solution is pretty simple now that it's all done but was elusive while trying to get everything tightened properly.

You can do the R1 Fork Conversion and not have your lower triple and stem drilled then pinned as described in the guide.  In order to do it, mods are required on both ends of the steering stem.

Bottom of the stem.  The R1 stem is tapered so if it is pressed out from the bottom up, it will enlarge the hole.  Mine was done this way so to get the FZ1 stem to fit, a bead was welded onto the bottom of the FZ1 stem then ground down to fit the hole.  Falcon 269 describes a way to remove the stem from the R1 lower triple without stretching the hole in Post 115 of the guide I linked to above.  It is my understanding that done this way, the FZ1 stem will fit without needing any modifications.

Top of the stem.   Once it's flush, you will need to have the stem turned down on a lathe at the top bearing sleeve (see pic below where bearings are installed) about 1/4" and extend the threads about 1/8" to be sure you have the correct distance from the top of the bearing to the bottom of the thread so that it will be properly installed in the neck.  These dimensions worked for me but you should measure the distance to be certain.

I switched from the OEM roller bearings to tapered ones like Kosmic Kartman from the UK Fazer forum did.  Here's his pic of the new and old lower triples with the stem pressed in.

R1 lower triple with FZ1 stem and tapered bearings on left,  OEM FZ1 lower triple with OEM bearings on right.
There's a pic in Falcon's guide that compares the FZ1 and R1 stems if you want to see the difference.

Spacer.  You'll need a spacer to fit over the top of the stem so that the upper triple will fit.  There's a great description of one you can have made in the Guide.  When using the modifications I listed above, you will need to have the spacer a little longer so it will cover the nut for a cleaner look.  I used the spacer I already bought from Justy on the Fazer forum but Devilsyam has them available too.  It's not as neat, but you can't tell unless you're looking for it.

If measured properly, then you can re-use the FZ1 top nut.  Mine was a little off so the cap on my top nut is hitting the stem.

I may be able to resolve this by getting a new spacer.

Upper Triple.  You can use the R1 Upper Triple as described in the Guide like I did with my initial install.  I didn't really like the way it looked nor the awkward location of the ignition so I replaced it with a Gen2 FZ1 upper triple and painted it black.  In addition, I replaced the Gen2 FZ1 risers with lower ones from my Suzuki VX800.  Another lower riser option is ones from the Suzuki SV650.

Gen2 FZ1 upper triple with Suzuki VX800 risers and bridge.
Before and After.

I'm very happy now that this is all fixed.  I'm still not sure if I'll like the lower risers but that's a simple change if I don't.

Other posts about the Front Suspension:

Thanks for reading,
patrice, theWolfTamer

1 comment:

  1. 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.
    from http://fazer1000.yuku.com/topic/3408/R1-Fork-Conversion-Guide?page=1#.VvIdzWR95ZJ


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