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Friday, December 3, 2010

Pit Bull Stand

I like to keep my motorcycles on race stands when I'm not riding them. It keeps the tires off the ground (avoiding flat spots) and makes maintenance simple.

The design of the VFR1200 final drive makes the use of a conventional (rear axle) stand impossible. Certain "single sided swingarm" designs can accomodate special stands but only when they have a hole through the middle, like a Ducati or a BMW. The VFR has no such passage.

Honda offers a permanent centre stand for the VFR that mounts on a pair of dropouts on the bottom of the frame. The centre stand is very handy for a chain-driven bike like the VFR800 where you need constant upkeep of the chain but on a shafty like the 1200 it doesn't make sense to carry the weight and bulk (and reduced cornering clearance) of the stand everywhere you go. The Honda centre stand is also very pricey.

Pit Bull makes a stand specifically designed for the VFR1200 that uses the mounting points for the factory  centre stand. I love their products... they are built in the USA with quality materials and fine craftsmanship. There are many cheaper "made in China" knockoffs but Pit Bull is (literally) the golden standard. A tag on their packaging proclaims "This stand will outlast your bike" as quoted by number 34 'living legend' Kevin Schwantz. I can attest to this... I've had my same set of Pit Bull race stands through 3 different motorcycles. That's another great thing about Pit Bull stands: they're (mostly) universal. Just adjust the lifting points and / or insert the appropriate pin and they work with all modern sportbikes. But as I said, the unique design of the VFR neccessitates a special stand so I bit the bullet and ordered one from Bayside Performance out of Vancouver. Shipping took a long time but only because the stand had to be special-ordered from Pit Bull in Alabama. The pricing was excellent though and their service and communication were great.

Wednesday, December 1, 2010

Not Just any Shaft Drive

A lot of development went into building the single-sided shaft drive for the VFR1200FA.

Here is an article from Honda:

Progress – the VFR Drive Shaft Up Close

It's a first in the history of the VFR for Honda to equip the VFR1200F with a shaft drive. But not all drive shafts are created equal. The design effort that went into ensuring extremely low-reaction operation for this component is more than remarkable and warrants detailed examination.

The shaft drive on the Honda VFR1200F is something special. Integrated into the single-sided swing arm, its design impresses for its unusually low-reaction operation. Motor cycle riders who are used to machines with chain drive to the rear-wheel and test ride a VFR1200F for the first time often discover that there is little or no noticeable difference. And motor cycle riders who are used to other shaft-drive machines are astonished on their first VFR ride by the smooth transmission of power and the absence of the typical accompanying traits.

... more

Did the Honda technicians perform some kind of magic? Let's resist the temptation to answer "Yes". Let's say instead that innovative development and design went into providing a shaft drive that sets new standards from a functional point of view. Several factors contribute to the impressive result.

First the basics: The drive shaft transmits engine power to the rear wheel and rotates on the left side, sealed in the one-piece, cast aluminium single-sided swing arm in the drive shaft tunnel. The final drive housing is flanged to the single-sided swing arm.

One special feature that distinguishes the VFR design is offset axes. The drive shaft and the swing arm in which the shaft rotates do not run on a parallel axis but at a pointed V-angle to each other. The mount for the swing arm on the frame is offset upward, so that the drive shaft can run below it directly for deflection at the transmission output.

This design refinement offers two benefits: First, a continuous swing axis can be used, which benefits the overall stability of chassis and swing arm mount (shaft-drive bikes mostly have to put up with short pins on the left and right to carry the swing arm in order to make room for the drive shaft running behind it along with a front universal joint). Second, Honda's design with offset axes does away with an additional torque bracing using lever systems against the frame, which not only saves weight but helps to achieve a clean look.

Anyone looking at the drive shaft assembly of the VFR1200F from the side who draws an imaginary line from the centre point of the wheel to the transmission output and then observes the position of the swing arm bearing on the frame can clearly recognize the upward offset. The benefit of this design is that reactions to load changes are successfully suppressed. Normally, with shaft drive the motorcycle lifts when the throttle is opened and it drops when the throttle is closed, an effect that is more or less pronounced depending on the model. This idiosyncrasy is foreign to the VFR1200F.

The shaft drive of the VFR1200F is astonishing in all riding situations for its smooth transmission of power. No shaft jacking, no stiffening of the springs under acceleration load, no scrunching when shifting through the gears, no clunking from the rear end in energetic braking maneuvers when the foot brake is used as well.

The exemplary manners of the secondary drive are helped out by the elaborate design of the drive shaft. At the rear end, it is fitted with a constant-velocity joint (instead of the usual universal joint) to transmit rotary motion consistently and smoothly even at large deflection angles. A plunging function additionally ensures length compensation as the rear wheel goes through jounce and rebound. The constant-velocity joint, which is about half the size of a Red Bull can, is completely sealed, filled with special grease and requires no maintenance.

Hint: If you enter the term "constant-velocity joint" in Wikipedia on the Internet, you will find animation that clearly visualises the ability to articulate forces smoothly.

Constant velocity joints are widely used in automobile design, for example on drive shafts on front-wheel drive cars. Their use on bikes, on the other hand, is not usual. The Honda VFR1200 is currently the only motorcycle on which this technology is used in the drive shaft area – although it is not the first. As a marginal comment for history buffs let us note: Only the shaft drive on the Van Veen OCR 1000, a Wankel-engined machine produced in Holland in the seventies, was also equipped with a constant-velocity joint.

But let's get back to the drive shaft on the VFR1200F. This component is fitted with the aforesaid constant velocity joint at the rear and with a universal joint at the front. Between them, a rubber damper is vulcanised in a tubular sleeve on the shaft that permits a certain amount of torsion. The drive shaft is meshed to the pinion that transmits the power to a ring gear and finally to the rear wheel mount. Three more damping elements can be found in the engine in addition to the rubber damper on the drive shaft. So the VFR1200F is equipped with a total of four dampers in the drive train, which contributes to its smoothness and the untroubled pleasure of riding with shaft drive.

The final drive housing with ring gear and pinion is designed as a closed system, which is also something new. During operation, the oil in the final drive heats up and expands; in order to equalize pressure in the housing previous Honda shaft drives were fitted with a cast-in vent cap. That is different now. Special shaft seal rings are used on the VFR that can withstand higher pressures. The pressure provided by these seal lips provide reliable sealing without the need to provide extra pressure compensation at the housing. The drive shaft housing could be made smoother and more modern looking on the outside without the vent cap.

It is perhaps also worth noting that ring gear and pinion are shot-peened in the manufacturing process at the Honda Kumamoto factory. As a result, the surface of the material is smoothed again and compressed after milling, being hardened only afterwards. The surfaces are made particularly resistant to wear as a result. The rear axle housing is filled with SAE 80 transmission fluid that is particularly stable under pressure. Because of the special mesh on the ring gear and pinion, very high flank pressures are created on both sides of the gear. The molecules of the hypoid gear oil are not crushed between the metal surfaces so that lubrication remains constant.

The drive shaft of the VFR1200 is visually more compact, the housing of the final drive smaller in diameter and more compressed than is usual. This is also a consequence of the design because the bearing for the rear-wheel carrier that sits internally in the usual construction is now placed outside. The diameter of the ring gear could be reduced accordingly and the pinion moved further inboard. The overall structure ends up saving more space. Note for technology mavens: The tooth flank clearance of the ring gear and pinion can be adjusted axially (by means of adjusting shims), the specification is 0.05 to 0.15 mm.

As a technology showcase, the VFR1200F has a lot to offer: V4 engine with unique cylinder arrangement, Big-Bang ignition sequence, Unicam cylinder heads, six-speed gearbox with slipper clutch, drive-by-wire throttle grip, aluminum chassis, single-sided swing arm, six-piston brake calipers, Combined ABS, layered fairing, the most up-to-date design, high-quality paint, impressive pannier system and and and. And don't forget the optionally available dual clutch transmission.

The drive shaft of the VFR1200F shines as a highlight in its own right as well. An easy-to-maintain rear-wheel drive, contemporary modern design and extremely low-reaction, allowing not only the outstanding experience of the benefits of automatic shifting with interruption of the power flow but which can also instill enthusiasm when changing gears manually. Just to call the drive shaft of a VFR a drive shaft does not do justice to its superb operation. So instead take a respectful look at it at the next opportunity. Or even better – ride it.

Wednesday, November 3, 2010

Brad Gavey VS the VFR1200

When I was a part of Brad's race team and school, we had our own expression that got used often. To "Gavey" something was to destroy or otherwise damage a mechanical device. If you overtorqued a bolt and stripped some threads, you Gavey'd it. If you just finished rebuilding the motor on your racebike and blew it up on your first lap out, you Gavey'd it. Plenty of Ducati transmissions have eaten themselves and become Gavey'd. It isn't neccessarily ham-fistedness or abuse... Brad is a smooth and fast rider... it's just that he takes things beyond their limits. In a 7-round race series this year, he entered 4 different bikes... not because he had the luxury of a multi-bike race fleet, but because he couldn't keep one running for more than 2 consecutive races. And he still won a championship.

In spite of his history of mechanical molestation, everyone wants Brad to try their bike. They want to hear that their bike is the greatest he's ever ridden. I guess I'm no exception. His opinions mean a lot. He has ridden hundreds of different bikes for probably hundreds of thousands of street miles and thousands of race laps. He knows what he's talking about, and he shoots from the hip.

Yes... in spite of his history of mechanical massacre, I wanted Brad to have a ride on the VFR. I trust him not to wreck it, and I trust the big Honda's ability to take punishment. I had a rare day off work today, and an even more rare warm weather forecast, so I went out for a spin and followed Brad around for the a few hours; he on my VFR1200, and I on his 2010 ZX-10R, then his B-King.

He was quite pleased with the VFR. Here are some of his observations:

-smoothest most comfortable bike he's ever ridden

-tires are shit. Good for protecting the rim and that's about it. He was spinning the back tire all over the place. He recommends the Michelin Pilot 2CT instead.

-falls into turns. (an observation I've also made) This effect is multiplied by the squared-off profile of my worn back tire

-sounds great, looks great. Flawless fit and finish

-carries its weight well and feels lighter than it is

-great brakes, though he would like to disable the ABS

-more likely to lose his license on this than his ZX10R... never feels like it's going as fast as it really is

-plush suspension, good handling but could benefit from a heavier rear spring

-barely noticeable shaft drive... but would still prefer a chain

-feels the throttle "hunting" a bit at steady speeds

-perfect bike for a trip down the west coast.

We had fun afternoon. Brad was impressed with the VFR and I got to try some pretty cool (and fast) motorcycles.
No motorcycles were Gavey'd in the making of this video:


Switchable Power Modes Part II

A member on an enthusiast board had some questions and comments about my power mode switch. I thought I would repeat our conversation here... maybe it will be informative to others.

Warren's words in italics:

So... Looking at your blog, it appears that the VFR is doing what so many other high power motorcycles have done in the past with restricting the lower gears to prevent early termination of it's riders. Namely, the GSX-R and the 1000RR.

That's my best guess. I've pondered about the restriction being some sort of mechanical failsafe, but I really don't think that's the case.

Both of these bikes have products that do essentially what you do with your switch, however they have "smarts" built into them so that the instrument clusters continue to read the correct gear.

For example, Ivan's make a smart TRE:


The company that make the speedo healer has the X-TRE:


But more interestingly, Bazzaz has a product called the Z-Bomb:


But as far as I can tell when looking at the installation instructions, it attaches to the Throttle Position Sensor. What are your thoughts?


Thanks in advance,


The wiring layout in the VFR1200 makes it difficult to avoid the gear indication error when the bike is in de-restricted mode. There are 7 individual gear position wires which run directly from the gear position sensor into the ECU and transmit 7 individual gear signals. It's simple, so it's easy to hack. After that it gets tricky. The ECU interprets those individual signals, decides what throttle and ignition map to use, and then encodes it and sends an encoded digital pulse signal through a single wire on the serial link to the combination meter (instrument panel) to be displayed on the gear indicator. To get an accurate indication on the gear while in de-restricted mode, you would have to decode the serial link. I think that's what Ivan has done with his Smart TRE chip for the gixxer. It's a complicated solution. It can be done, but it would take some work and savvy computer skills. On a bike like the Gixxer with its enormous market base, it's worth it for someone like Ivan to put in the time. With very few VFR1200s on this side of the pond, it's hard to imagine anyone bothering.

The Z-bomb is a little different. Honda programmed the American market 08 CBR1000RR to retard the timing at high RPM at full throttle, robbing it of 7 or 8 peak horsepower. It was suggested that this was to pass noise tests which are measured at a percentage of maximum RPM at full throttle. As far as I can tell, the Z-bomb tricks the ECU into thinking that the throttle isn't fully open, therefore allowing the full ignition advance and replacing the stolen horsepower.

The Gixxers and CBRs use a timing retard to limit power, but I still think that the VFR is limiting power through its "throttle by wire". (which the GSXRs and CBRs don't have yet) If I'm correct, that would mean that there are 2 throttle maps, one restricted and one unrestricted. The ECU is interpreting the gear position signals and telling the throttle valve motor which map to use. The gear position sensor is a crude but effective bypass.

There may be a more elegant solution but I'm just not smart enough to crack it. Studying the wiring diagram, there are a pair of wires which I suspect may contain the answers. There are 2 wires that run from the ECU to the TBW motor labeled TBW MTR+ and TBW MTR- on the throttle valve side, and labeled TMOM and TMOP, respectively, on the ECU side. If my hunch is right, these could be the wires that send the throttle map signals. My guess would be that TBW MTR- could transmit the restricted map. If that were the case, you could cut that wire and splice it to the TBW MTR+ wire so that the throttle valve motor never recieves the restricted map.

Again, I'm just guessing... and I don't want to be the guy to test it. If I'm correct though, this type of mod would de-restrict the bike without giving a false reading on the gear position. A switch could be installed easily with this mod as well.

I just need somebody smart to review my theory. Where's that Dutchgixxer guy?

Here is the wiring diagram and the wires I'm referring to. The wires I'm talking about are circled in red:

Edit: TMOM and TMOP appear to be the power supply for the throttle motor. (wires A9 and A10 coming off the ECU. Cutting or altering them will cause the throttle motor to quit. Not advised. :)

Tuesday, November 2, 2010

Honda CrossTourer Official

From Asphalt and Rubber:


Man what a beast!

Those forks sure look wimpy.

Crossrunner 800 Official Release

From the good people at visordown.com:


I jumped to conclusions on the brake pedal... it definitely has one.

Unless I'm wrong, this is basically new packaging for the VFR800. And it will probably be a great street bike. It's about time the VFR stopped posing as a race bike... it hasn't been one for many years. This makes more sense.

Monday, November 1, 2010

Honda CrossTourer Concept and Crossrunner

Honda have said that they will unveil 2 V4-powered adventure-style bikes at the Milan show this week. (opens Nov 2)

There is the VFR800X that I posted about earlier and a rumored VFR1200-based adventure bike. The VFR800-based model (CrossRunner) is supposed to be production-ready, while the 1200X (Crosstourer) will probably be a 2012. Other moto blogs have mistaken the 1200 Cross Tourer for the 800X Cross Runner.

Someone at Oliepeil (Dutch moto mag) got a hold of some spy pictures today before the show has opened. One of the pictures shows the "Crosstourer Concept" which is clearly based on the VFR1200.

The image of the Crosstourer has some interesting clues. It seems to have the (a version of) VFR1200's frame, swingarm and final drive. (and presumably engine) There are hand guards, extra running lights, lots of ground clearance, a big gas tank and spoked wheels. If they include a sophisticated electonics package and all the gadgets, it could be a serious competitor for the R1200GS and Multistrada 1200.

Saturday, October 30, 2010

Unicam > SOHC

I've read a few remarks in forums and comments sections of moto sites about Honda's choice to use a "cheap inferior" SOHC valve layout on the VFR1200FA. I want to explain the differences here and clear the air.

Technically,  the Unicam design is a Single Overhead Camshaft layout. There is one camshaft (per cylinder bank) placed overhead of the valves. But this design, which is unique to Honda, has some key differences and advantages.

A conventional SOHC cylinder head has a camshaft mounted down the middle of the head with a rocker shaft on either side. The valves are opened with rocker arms. It's simple and effective, but there are some disadvantages compared to a DOHC design... The main disadvantage is the added reciprocating weight from the rocker arms. The added weight limits the engine's rev ceiling. Another drawback might be the compromise of the combustion chamber shape. The spark plugs and ignition coils cannot be placed in their most efficient location: top center of the combustion chamber. The camshaft sits in the way.

On a DOHC cylinder head, the camshafts are placed directly over the intake and exhaust valves on opposite sides of the head. There are no rocker arms or shafts and the ignition coil and spark plug sit directly over the center of the combustion chamber. It can rev higher than a SOHC but it requires a bit more maintenance and it's bulkier.

Honda's Unicam is a hybrid of both designs. There is only one camshaft, but instead of sitting down the middle of the head, it is located directly above the intake valves, like a DOHC. The intake valves are opened from directly overhead through a solid lifter. (with shim adjustment) The exhaust valves are opened with tiny little roller rockers, one for each valve. The exhaust valves are smaller and lighter than the intake valves, and they don't open as far... so the added reciprocating weight from the rocker arms is less of a factor, and high RPMS are still possible. There is also less stress on the cam drive compared to a DOHC. Just one (shorter) chain is required to turn the camshaft, and a larger sprocket is used for more torque multiplication and less stress on the chain. The chain also doesn't have to bend through a complex path, so a simpler cam chain tensioner (with less potential for failure) can be employed. Valve adjustments are slightly simpler than a DOHC, because the exhaust valves have threaded adjusters at the ends of the rockers, which eliminates half of the tedious shimming work.

Honda introduced this design for 4-stroke motocrossers and off-road bikes. The reduction in bulk and mass is especially important to compete with flyweight 2-strokes. It made sense to employ this design on the big V4 for the VFR1200F. V4s are bulky engines and are tricky to package compared to the typical inline 4 on most sportbikes and the Unicam design helps make it a bit more compact. (smaller overall than the DOHC VFR800 motor) Very little performance is sacrificed compared to a DOHC and maintenance is a bit simpler.

Thursday, October 28, 2010

Honda CBR250R

Honda have announced that their redesigned CBR250R will be offered in Canada and the USA next year. When Honda brought the CBR125R to Canada a few years ago I liked it so much that I bought one. It was by no means a high-performance motorcycle but it was great fun to ride

This new CBR250 would make a great "little brother" to my VFR1200F. Don't tell my wife.

Wednesday, October 27, 2010

Honda VFR800X Adventure

Honda have been releasing teaser sketches over the last few weeks that hint at an upcoming V4 "adventure" style bike which will be unveiled at the Milan show next month.

From what I can see, the bike they've come up with isn't an "enduro" style adventure bike like the BMW GS or KTM 990 Adventure, but more of a "standard" sporty roadbike meant for sport touring... much like the Suzuki V-Strom, Kawasaki Versys or Triumph Tiger 1050.

This was the original sketch. Some of the enthusiast boards started buzzing about a VFR1200-based adventure bike. The sketch clearly shows the continued use of the "layer concept" fairing as debuted on the VFR1200F... which will surely be incorporated into all future Honda sportbikes. The sketch also clearly shows an upright riding position with high handlbars.

This is the second sketch that was released a week later. The styling reminds me of the Versys. The layer concept fairing is shown again and Honda hinted at a "floating instrument panel"

This final sketch was released today. Clearly this isn't meant to be a true enduro adventure machine, but more of a "real world" sporty standard bike with an upright riding position that should be comfy for long distances. The bit of engine and frame visible is clearly carried over from the VFR800 VTEC, and not a derivative of the new 76' unicam V4 in the VFR1200. Maybe I'll be proven wrong but this to me looks like the replacement for the VFR800. There looks to be a lot of carry-over parts, including the wheels and conventional fork. If they've made it a bit lighter and more rideable than the 800 it could be a big hit. If what I think is true, and it's a re-styled VFR800 then the price should be quite reasonable too.

edit: The bike in the 3rd sketch doesn't have a brake pedal but the second sketch clearly shows 2 levers. These sketches usually contain important clues so I don't think that's just an oversight. You can clearly see a pulser ring on the front rotor for ABS... I wonder if Honda have fitted a simpler combined ABS that is operated only by a hand lever? I could imagine it having a delay valve which progressively increases rear braking. Can't wait to find out.

Sunday, October 24, 2010

Stebel Nautilus Air Horn (second horn upgrade)

I shared my horn upgrade post on VFRdiscussion.com and a few different people recommended installing a Stebel instead.  I was curious, so I did some browsing around and learned that the "Stebel" is an Italian-made 12V airhorn that is obscenely loud. I consider myself obscene so I went ahead and ordered one up from the good people at Twisted Throttle.

The biggest obstacle with the Stebel is its bulk. It incorporates a compressor and is rather large. There's no possible way that it would fit in the stock location (the previous FIAMM barely did) but I found a perfect location.

I noticed that the ABS controller bulges out quite far from the frame on the right side of the bike. The space on the opposite side of the frame is vacant and the fairings are symmetrical so it stood to reason that there would be room in that location. Hell there was even a threaded hole on the frame to use as a mounting point and a chassis ground nearby to make wiring easier.  After this photo was taken I reinstalled the top fairing / headlight so I could make sure I had clearance where I needed it.

As you can see, the Nautilus is substantially larger than the previous Fiamm and immensely larger than the stock "meep meep" horn.

A device like the Nautilus draws substantially more current than the stock horn, and therefore has the potential to fry the light duty horn switch. The solution is to wire it through a relay. Basically a relay is a heavy-duty switch which is contolled by a light-duty switch. This also allows the new horn a direct connection to the battery so it can blast away to its maximum effect. I'm not very skilled electrically... this would be my first encounter with a relay and I learned all this as I went. I used the aid of a handy online tutorial. I wanted a clean installation so I bought some quality automotive connectors and a fuse holder.

I used the soft metal bracket from the Fiamm, test-fitting it and bending it into a "Z" shape that would keep the Nautilus tidy against the frame.

Here is the Bosch relay that came with the Nautilus. All hooked up. The heavy white wire is my power wire. I used some heavy-duty speaker wire from an old kit I had. Comically, this wire was labeled "subwoofer".

I drilled a little hole in the inner cowl where I would mount the relay next to the upper harness connector.

I secured it with that old favourite fastener of mine... a windshield screw. (I have a package of them) It is the perfect size and provides a "shock mount".

Here is the red relay secured in place.

And here is the Nautilus bolted in tight against the frame in the desirable downward-facing position. This is exactly where the bulky ABS controller mounts on the opposite side of the bike. I test-fitted the left fairing panel to make sure it fit.

Here is the fuse holder and the power wire running up to the relay:

I briefly tested the horn inside the garage... big mistake. I gave myself a splitting headache. It's FUCKING LOUD!!!

I wheeled it outside to test it properly and piss off my neighbours. Turn your speakers all the way up and press your ear firmly up against one of them to fully appreciate the experience:

Quartet Harness

 Honda offers a "quartet" harness that makes it really simple to hook up factory accessories. (such as the heated grips or 12v outlet offered on the Honda web site) Since it's cheap and I already had the bike peeled, I figured I'd pop one on there. I ordered from David Silver Spares once again in the UK. It was cheaper than buying from a US dealer on ebay.

The instructions are simple. Locate the waterproof accessory plug. It is electrical taped to another harness. Remove the tape and the dummy plug.

If you pull back the cover you can see the 4 plugs for hooking up the factory accessories.

Use the supplied zip tie and clamp to secure the harness firmly in place.

Now I just have to get some accessories.....

Tuesday, October 19, 2010

MotorcycleUSA Comparison


Pretty much mirrors how I feel about the VFR.

I like this comment in particular:

“Sometimes I wonder what market Honda was trying to attract. I think the VFR was designed for a young man who just doesn’t want to give up his sportbike, but wants to do a little more travelling… so just take a sportbike and add some bags.”

Yep sounds about right.

Thinking out loud RE power limitation

I have another theory on the torque limitation in first and second... It might be to keep the side gear case with its coil spring / cam damper from blowing up. A sudden high-torque hit will bang that cam into the coil spring really hard.

I wonder.....

Sunday, October 17, 2010

Switchable Power Modes

Electronics aren't my strength but I figured out that I could wire a DPDT (Double Pole Double Throw) switch to change modes between the normal restricted mode and the hacked de-restricted mode. Why bother with a switch? Dutchgixxer has de-restricted his VFR1200 and reports that he considered changing it back to stock because the torque was so responsive in 1st and 2nd gear. His bike wanted to wheelie and spin if he wasn't cautious with the throttle. Also, the inaccurate gear position sensor could get annoying in the de-restricted mode. I figured a switch would be nice if I changed my mind, that way I wouldn't have to go back in and keep changing it back and forth.

I decided to place the switch under the seat. This way it can't be switched on the fly... I will have to stop the bike, take the key out of the ignition and unlock the seat to access the switch. I don't want it to be changed on the fly because if it were changed in 1st or 2nd gear on the fly, the interruption in the signal could cause a fault, thereby triggering an engine light which in itself doesn't have any negative effects but it's annoying to clear the trouble code.

The first thing I would need to do is repair the wiring that I hacked up near the harness. I kept it tidy with shrink-sleeve insulation and wire ties.

 The gear position sensor sits on the end of the shift drum, right next to the shifter spindle. I removed the
shifter linkage and the plastic side cover to gain easier access.

On the inside of the frame spar there is a connector for the GPS. The connector needs to be released from its clip. The group of wires with the woven insulation goes directly into the GPS>.

I spliced 2 lengths of wire into the 3rd gear wire on the ECU side. I would run them up the inside of the frame and under the tank to the battery area.

This is the DPDT ON-ON switch that I picked up from Radio Shack. There are 6 poles. I ran the 1st and 2nd gear wires on the GPS side to the middle poles. The 2 3rd-gear wires ran to the outer poles on one side, and the 1st and 2nd gear wires on the ECU side ran to the other 2 outside poles. Now when the switch goes toward the 3rd gear side, the 1st and 2nd gear wires will be shorted to the 3rd gear wire therefore the ECU will receive a 3rd gear signal when the bike is in 1st or 2nd. When the switch is in the other position, the bike runs normally.

This is the plug coming from the GPS. The first and second gear wires are cut and the opposite ends run to opposite poles on the switch.

This is my crude schematic. You can see that when the switch is on the left side, the ECU (on the right) can only receive a 3rd gear signal.

I drilled a little hole in one of the baffles under my seat to mount the switch. I sealed the 6 terminals up with a blob of silicone and taped it up tightly. The 6 wires were tidied up with some wire ties. When this switch is in the "up" position the first 2 gears are de-restricted.

Here is my switch:

I threw on a helmet and rode the naked VFR up and down my street a few times, stopping in between to switch "modes". The result is exactly what I expected... In the de-restriced mode the hesitation before 5500RPM is gone. Instead, the torque rushes full-on from idle. It's drastically more responsive. It makes the natural restriced mode feel sluggish.

Tuesday, October 12, 2010

Gear Position Sensor Mod... or... "how to de-restrict power in first and second gear"

One of the most common complaints of VFR1200 owners is the power restriction in first and second gear. My dyno runs from an earlier entry clearly show the "torque hole" that occurs in first and second. I've speculated that the reason for the restriction is to reduce wheelspin in the lower gears. (when Honda should have just equipped the bike with proper traction control) I've also speculated that the restriction was the result of a "traction map" that reduced the throttle opening at those specific RPMs in 1st and 2nd.

A fellow enthusiast on a discussion board argues that the restriction is a result of a timing retard in those circumstances... which I have no reason not to believe. (this would be a much simpler solution to execute)

That same enthusiast (dutchgixxer on vfrdiscussion.com) hypothesized that the restriction could be eliminated by "fooling" the ECU into thinking that the bike was in 3rd gear while in first and second. This would mean that it would revert to its full power map. He studied the wiring and provided a simple schematic on how to fool the ECU.

The VFR1200 has a very sophisticated gear position sensor (GPS) that uses an extremely accurate potentiometer on the shift drum. I suspect that this is "trickle-down" technology from the DCT version where the GPS plays a crucial role. Each gear position has its own wire going into the grey serial plug on the ECU. This makes it relatively simple to fool the computer.

I can't take credit for the concept of this modification, but I am pleased to provide a set of instructions.

The tank must be lifted to gain access to the ECU.
The grey connector is unplugged.

I cut a slit in the shrink sleeve to gain easier access to the wires. I separated the black and yellow wire. This is the 3rd gear wire which is grounded when the GPS detects that the transmission is in 3rd gear.

I carefully stripped away a bit of insulation and spliced in 2 short pieces of wire. I twisted them together, used a little blob of solder and taped it up.

The black and brown wire is the first gear wire and the light green and red wire is the 2nd gear wire. The third gear wire is spliced into the 1st and 2nd gear wires on the sensor side. I taped the ends of the wires on the ECU side to prevent shorting.

All taped up and back together. Now when the transmission is in 1st or 2nd gear, the ECU will get a 3rd gear signal. Full power will then be available in those gears. The only drawback is that the gear indicator display will give a false reading in 1st and second. It will read that the transmission is in third gear.

It could be a while before I ride again but I'll report back on how the mod changes the power delivery.

Monday, October 11, 2010

EVAP Removal Mod

The VFR1200F is equipped with an evaporative emissions control system. The purpose of this system is to comply with California Air Resources Board vehicle requirements. It draws fuel vapors from the fuel tank, stores them in a canister, and then purges them into the throttle body to be burned in engine combustion rather than evaporate into the atmosphere.

It's bulky and unneccessary so I took it out. My "green" European readers may find this offensive but this is a motorcycle blog, not a political blog so I'll avoid discussing the perceived environmental consequences here.

Here is the diagram for the system in the repair manual:

Here's what it looks like, located under the tank behind the rear cylinder head.

I joined the fuel tank breather hose to the evap drain hose, essentially bypassing the canister.

This is with the EVAP tray removed. Underneath the tray is a heat shield for the rear exhaust headers. The rear shock is also visible here.

I plugged the "purge solenoid valve to throttle valve" hose with a big bolt. This line goes to a manifold under the throttle body which splits it into 8 individual lines, 2 going into each intake port. To thoroughly remove the system, you could remove all the lines and insert vacuum plugs in the holes. It would be a lot more work and likewise a lot tougher to reverse if you had to.

The tray is reinstalled but with the solenoid and canister removed. I duct taped the solenoid plug and throttle hose to the tray so they won't rattle around.

This is what was removed. I threw it in a box of stuff I've removed from this bike... the box is starting to get heavy.

As was the case with the PAIR solenoid, the EVAP solenoid does not provide feedback to the ECU and therefore shouldn't cause a trouble code or malfunction light by being removed.