Click on image for a Flickr photo album of this bike My 1993 VFR750, aka Project 39, was on the lift this past week to complete some small projects. I'd also been using the bike for tuning rebuilt carb sets for the past two months.
First up was the switch to a different set of carbs. I decided to custom jet a set I rebuilt over the winter in order to see if they would compliment my intake and exhaust setup; a K&N performance filter paired with a Delkevic slip-on. I should make clear that this combination does not require carb jetting changes on the VFR, rather I'm just looking to see if mild jetting increases would be noticeable one way or the other. The only significant change was to use #124 main jets from a (DynoJet?) jet kit, which were a bit larger than the original Keihin #130 (yeah, confusing). As best I can determine, I would put the new jets as equivalent to a Keihin #135. In addition, the slides' bleed holes were drilled larger, per jet kit practice. Slide needles are original (with one shim added) as are the #40 pilot jets. K&L float valve assemblies and new air cut valves were installed and the pilot screws set at 2 3/4 turns out.
On the lift, the carbs sync'd perfectly and throttle response seemed spot on, but the proof would come with a test ride, sampling throttle response and pulling power throughout the range. That happened early this week...and the result? The new carbs worked great. A smooth, strong 4th-gear pull from 2000 RPM to redline, no bogging or flat spots, quick and precise throttle response whether at parking lot speeds or rolling on exiting a corner. No further adjustments required. Are they better than the stock-jetted carbs? Without the ability to do a back-to-back comparison, my butt dyno isn't conclusive, but the "new" carbs seem to pull revs quicker than the originals. In any event, I'm pleased, so they've found their forever home on my VFR.
First up was the switch to a different set of carbs. I decided to custom jet a set I rebuilt over the winter in order to see if they would compliment my intake and exhaust setup; a K&N performance filter paired with a Delkevic slip-on. I should make clear that this combination does not require carb jetting changes on the VFR, rather I'm just looking to see if mild jetting increases would be noticeable one way or the other. The only significant change was to use #124 main jets from a (DynoJet?) jet kit, which were a bit larger than the original Keihin #130 (yeah, confusing). As best I can determine, I would put the new jets as equivalent to a Keihin #135. In addition, the slides' bleed holes were drilled larger, per jet kit practice. Slide needles are original (with one shim added) as are the #40 pilot jets. K&L float valve assemblies and new air cut valves were installed and the pilot screws set at 2 3/4 turns out.
On the lift, the carbs sync'd perfectly and throttle response seemed spot on, but the proof would come with a test ride, sampling throttle response and pulling power throughout the range. That happened early this week...and the result? The new carbs worked great. A smooth, strong 4th-gear pull from 2000 RPM to redline, no bogging or flat spots, quick and precise throttle response whether at parking lot speeds or rolling on exiting a corner. No further adjustments required. Are they better than the stock-jetted carbs? Without the ability to do a back-to-back comparison, my butt dyno isn't conclusive, but the "new" carbs seem to pull revs quicker than the originals. In any event, I'm pleased, so they've found their forever home on my VFR.
(Below) Next I addressed a wiring issue with the voltage monitor, sourced from Roadster Cycle (.com). This is a simple $30 LED dash light that changes color to warn of battery voltage drop. I first ran one on my ST1100 after experiencing charging issues on that bike, and having that reassuring green light glowing when hundreds of miles from home got me hooked on voltage monitors. When I initially installed it, I spliced into a convenient keyed 12v wire under the headlight fairing. As it turns out, this little guy is so sensitive that it wouldn't go full green unless wired directly to the battery (or very close). This, despite the fact that my charging system is fitted with Roadster Cycle's best, the "Super Mosfet Kit" which includes heavy duty wiring and a 30-amp circuit breaker charging at 14+ volts.
I tried, but it's stubborn, only going full green when near the battery. The issue with this wiring is that it's no longer keyed to the ignition, so it glows even with the ignition off. Jack from Roadster Cycle suggests that some guys like this as it appears to be an anti-theft light…and he's right. As as experiment, I let the bike sit for two weeks with the little light aglow, and measured only a .01 voltage drop in that time, so I guess it's not a factor, especially if you make use of a battery tender, which I do. However, just in case I ever wanted to eliminate that draw, I wired in a bullet connector under the seat. I suppose an inline on-off switch would have been more elegant, but also bulkier. You can see in the photo my wiring connection is at the circuit breaker…under the red cover. Where previously I had a sickly amber/green-ish light I now have a warm green glow. And yes, it does look like a bike alarm when unattended.
I tried, but it's stubborn, only going full green when near the battery. The issue with this wiring is that it's no longer keyed to the ignition, so it glows even with the ignition off. Jack from Roadster Cycle suggests that some guys like this as it appears to be an anti-theft light…and he's right. As as experiment, I let the bike sit for two weeks with the little light aglow, and measured only a .01 voltage drop in that time, so I guess it's not a factor, especially if you make use of a battery tender, which I do. However, just in case I ever wanted to eliminate that draw, I wired in a bullet connector under the seat. I suppose an inline on-off switch would have been more elegant, but also bulkier. You can see in the photo my wiring connection is at the circuit breaker…under the red cover. Where previously I had a sickly amber/green-ish light I now have a warm green glow. And yes, it does look like a bike alarm when unattended.
(Below) My next project was one I'd been putting off for some time. After suffering a garage tip-over 18 months ago (don't ask), I spent several months searching for a replacement right-side rider's footpeg bracket, as mine got a slight bend which resulted in the footpeg drooping. After buying and returning a similarly bent item, I finally found a straight bracket on eBay England. I then spent a full day grinding, sanding, more sanding and clear-coating the new bracket. With it up to the standard of the rest of the bike, I swapped the footpeg, brake master, brake light switch, heat shield and brake pedal onto the new bracket and was rewarded with a good-looking, straight assembly. A simple tip-over can involve a lot of money and effort to make right — this was just one of the required repairs.
Finally, with the fairing out of the way, I decided now would be a good time to flush the cooling system and install a new thermostat. The temperature gauge on my '93 seems to sit low in the range, so rather than wonder about the thermostat not functioning correctly, I elected to replace it; part #19300-ML7-003 ($56, ouch!) along with a fresh fill with Honda HP Coolant. I happened to have a NOS thermostat on hand, which I'd paid "only" $32 for some years ago.
As it turns out, the thermostat isn't accessible with the carburetors in place, so…seat off, seat cowl off, fuel tank off, carbs off, replace thermostat, reinstall all of the above. Whew. A test run and system burp on the lift, and call this "little" task done.
With all these projects successfully completed, I coerced all the various fairings back in place, and declared Project 39 ready for the season.
As it turns out, the thermostat isn't accessible with the carburetors in place, so…seat off, seat cowl off, fuel tank off, carbs off, replace thermostat, reinstall all of the above. Whew. A test run and system burp on the lift, and call this "little" task done.
With all these projects successfully completed, I coerced all the various fairings back in place, and declared Project 39 ready for the season.
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