My VF1000R mod page
Updated 15 jul 2001 (for the last time - I no
longer own this bike)
The whole truth, and nothing but the ugly truth on VF1000R modifications.
This is my 1985 Honda VF1000R, which I purchased
in July of 1998. I found it sitting in someone's yard, and it followed
me home the next day. Enough storytelling, let's get on to the important
stuff - ripping it apart and making it a better bike. I've accomplished
the first part, and the second part is starting to come together. For history
and stats on this mighty bike, head over to my info
page. Read on further if you want to find out how to turn your bike
into a pile of parts for weeks on end.
Getting the basic package working.
This is the first thing I got to do to the bike
when I purchased it with 24,000 miles - put in a new clutch. You can see
the side cover removed in the photo if you look closely. Normally, this
wouldn't be anything special, but it does show the bike with the lower
fairing removed, and this did teach me an important lesson about motorcyles
- you can't just replace gaskets with instant gasket maker or other sealants.
The starter clutch and shifter shaft locate into the side cover, and both
will get bound up tight if a gasket isn't used. Remember to order that
gasket before taking the bike apart. Else, you can expect to torque
everything down tight, and the bike won't start (as the starter clutch
hub binds up against the side cover), and the shifter won't return to its
center position (the pivot for this goes all the way from the left side
of the motor to the right side, and locates itself agains the right-side
cover). This was probably my first lesson in the fact that bikes
are not built like small-block Chevy engines.
Breaking the mold.
Here's the next mod I performed. Well, not exactly.
You see, the stock shifter is too short, especially when wearing heavy
boots. The kickstand really intrudes on the area immediately under the
shifter, and so the only remedy is to lengthen the shifter. Orginally,
I had my friend Chris weld on an extension that I had turned on a lathe.
This worked for about 5,000 miles or so, but it eventually broke (ironically
enough, Chris was riding it at the time). So, I went in search of a replacement,
and came up with this item off a Honda CR80 dirtbike. It's better than
the original, but still not perfect.
There's plenty of parking around back, right
next to the shower...
This is where the project got a bit interesting.
Since the stock suspension and brakes are a bit weak (actually, they're
pretty pathetic), I decided upon an upgrade path that'd update those parts
to something a bit more modern. Luckily, Honda tends towards standard
dimensions for parts such as axles, fork tubes, and steerer tubes.
Forks:
We've now moved on from the shifter towards
other problems, namely the 16" front wheel and rather archaic forks. Some
parts from a 1994 Honda CBR600F2 were suggested as bolt-ons to fix handling
problems, so I went ahead and ordered some from an individual who gave
me a good deal from his crashed bike. So, I now have a bike in a bathroom,
and a shower stall with a set of F2 forks, wheels, and front brakes. This
part of the project took over four months, since I was in school at the
time and severely pressed for time. The F2 parts were picked as they retain
the stock speedometer drive (F3 bikes used a electronic speedometer driven
off the countershaft, so they lack provisions for a cable drive off the
front wheel). If you decide to give up the stock speedometer, there's a
variety of other forks that might work, such as inverted Suzuki forks,
and the CBR900RR parts. Unfortunately, the F2 forks are shorter than the
originals. If you mount them with the upper legs flush with the top of
the clip-ons (like the stock forks), you can expect the turn signal mounts
to hit the front fender under full compression at full lock. There also
may be interference between the fender and the radiator, according to some
folks. This issue is only made worse by the super-soft F2 springs. First,
get the right springs (I'm running
Race
Tech 1.0 kg/mm springs with 5wt oil, which was recommended by Race
Tech's suspension calculator). With the correct springs, these forks
really improve the whole bike. Next, run the fork legs just a bit below
the clip-ons. I run my about 10 mm shy of flush, and it works well. Continue
reading to find my proposed solution to this.
Exhaust:
The stock exhaust came off, but it took some
serious pounding with a deadblow hammer to loosen up the stock gaskets.
Next, I installed a Holeshot Vortex
4-1 system. This is a nickel-plated lightweight system with a baffle-less
"silencer", built by Hindle. It drops 35 pounds off the bike, and makes
a lot more noise than the stock setup. It installs fairly easily, but requires
a fair amount of high-temperature silicone sealant to prevent exhaust leaks.
For fun, fire the bike up without the silencer, and pretend that you're
sitting on the grid at Daytona. Even with the silencer installed, it's
still a loud system. Expect lots of praise from squids, and maybe a few
looks from the cops at full throttle. I'd really prefer a system
that lasts a bit longer, tho.ugh - the nickel plating certainly isn't real
protective of the thin-guage tubing underneath. If you have the money,
explore some sort of ceramic coating if you'd like the system to last more
than a few years. The alternative is the Yoshimura slip-ons.
Jetting:
After installing the exhaust, I fitted a Dynojet
Stage 1 jet kit and K&N filter. The K&N dropped in with typical
ease, while the carbs came off with typical difficulty. I also removed
the lid from the air box and kept it off, as the airbox is too small for
the motor (it's only about 3 or 4 liters), and the snorkels are very small.
I'm guessing that the small snorkels were installed for noise reasons,
as the intake noise almost overwhelms the exhaust at part-throttle. I haven't
done any dyno tuning on the carbs yet, but I did find the kit specs for
idle mixture to be way off. I started with the recommended 3 turns on the
mixture screws, and later went to 2 1/2 turns with much better results.
Front wheel and brakes:
With the forks, I used the F2 wheel bearings
and axle. If you'd like to keep the stock fork, the F2 wheel should work
with the 1000R's axle without any problem. You'll have to press out the
bearings to swap over the axle, though. The F2 rotors are placed slightly
closer together than the 1000R's rotors, but the stock calipers should
float enough to clear them without a problem, as long as you're still using
the stock thickness pads. Aftermarket pads may be too thick to allow the
caliper to float properly on the F2 rotors and wheel. I'd think that going
with the F2 wheel would provide an immediate improvement in handling with
a minimum of hassle. Placing a 120/60-17 tire on the front yields the same
nominal diameter as the stock 130/80-16, but with a much better profile.
Rear wheel and brakes:
Here's where the difficult part of the F2 modification
came in. The stock axle works fine with the F2 wheel, but you'll need to
cook up some new axle spacers (large washers can be made to work, but you'll
need to figure out the sizes since I've long forgotten). Since the stock
VF caliper didn't work with the F2 wheel due to the size of the caliper
and the large hub of the wheel, a new caliper was required. I ordered a
F2 caliper sight unseen, and found that the mounting bracket was totally
different. Shown is the small bracket that I added to the rear swingarm.
It's current constructed of mild steel bar, but I have a machined aluminum
one planned. The rearward bolt hole is the hose bracket mounting hole from
the old setup, while the front mouunting hole was drilled and tapped in
the swingarm. Additionally, a feature was created out of 0.120" wall aluminum
tubing and welded to the stock F2 caliper bracket, and runs in the slot
between the bracket and top of the swingarm. This is somewhat similar to
the stock F2 bracket/swingarm interface. I'm thinking of trying to do a
cut-and-weld operation on the stock caliper bracket to space it out from
the axle centerline, and then get a new rotor made with a correspondingly
larger diameter. This would allow the use of the stock caliper. The F2
caliper combined with the 1000R rear master cylinder provides just about
useless amounts of braking force. Some like to use the rear brake, some
don't, so it's a matter of personal taste. I usually only use it when riding
two-up, so it's not really a big deal to me.
Rear fender:
This is a shot of the rear of the bike, showing
the Holeshot silencer and F2 rear wheel. If you look at the rear fender,
you can see my trim work on it. I removed the stock plate bracket and light,
and removed the small panel from the bottom of the tail light reflector.
This illuminates the plate quite adequately. The stock signal were removed,
and I trimmed off the stock mounting tabs from the rear tail light mounting
bracket (I saved the tabs, as they could be easily welded on at a future
date). This made room for the Lockhart Philips flush-mount teardrop signals.
I can't overstate what this did to the appearence of the bike, as it's
much slimmer and resembles a HRC racebike from that era.
Ride height adjustment:
What you can't see in this picture is the lengthened
rear shock. The F2 forks, wheels, and tire sizes combine to lower the bike
by about 0.75". The Holeshot exhaust sticks down further than the stock
exhaust by about 1", which creates a serious lack of cornering clearance
when riding two-up. I fixed this by fabricating a crude ride-height adjuster.
I cut the lower clevis off the shock right at the weld, and welded a 12mm
nut into the bottom of the shock shaft with a TIG welder (this is no place
for flame or arc welding, just in case anyone is inclined to try). The
nut fit just about perfectly into the hollow shaft after I ground the corners
off of it. Then, I drilled a 12mm hole in the center of the clevis. This
gave me a clevis that bolted up to the bottom of my shock with a 12mm bolt.
Placing 0.375" worth of washers between the clevis and the shaft raises
the back of the bike by 2", which is the maximum amount allowed as the
swingarm will top out on the frame (it hits a small tab on the right-hand
pivot, if you wish to fix this problem). Then, bring the rear shock up
to 80psi or so, depending on your weight. I didn't play around yet with
thicker shock oils, but I suspect that it's make a significant improvement.
All of the above mods brings the rake up
to 24 degrees, and the bike handles extremely well at this point. I now
have a 160/70-17 rear tire (due to a second flat in less than 1000 miles),
instead of the more common 60-series piece that I was running earlier.
I think this tire, with its extra 1.2" of diameter and rounder profile,
really makes the bike turn-in better. It seems to complement the
ride-height increase.

Clip-ons:
Yet another mod, and maybe one of the most-significant
ones in terms of day-to-day comfort. As anyone who's ridden this
bike can tell you, the clip-ons just aren't in a comfortable position.
While addressing the length of reach is difficult, I found a way to raise
them up. You'll notice that the center of the bar itself sits above the
centerline of the clamp bolt in this photo. Originally, the clip-ons sat
below the clamp bolt centerline. Performing this mod is as easy as swapping
the clip-ons from side to side, but you'll need to drill the appropriate
holes for the locaters on the switchgear (the pens in the second photo
point to the old and new holes). While the clip-ons are off, note how heavy
they are - aftermarket pieces could easily drop five pounds off the bike.
I mentioned a solution to the fork length
problem. At first, I thought that machining a new upper triple-clamp with
a slight drop would be the best solution. With some thought, though, the
idea of mounting the clip-ons
under the triple clamp would free
up some fork leg length. The stock clip-ons will be way too low, however.
There may be more room for improvement on
this bike, but I jumped to another bike before reaching the full potential
of the bike.