Tag Archives: VFR

Fitting a new stator to the VFR

Last time, we discovered the cause of the VFR’s battery eating habit. According to the workshop manual, the stator coil was no longer functioning correctly. As you may have surmised, I left out most of the charging circuit tests that passed. There is beauty in brevity and my posts are rarely that!

The stator coil on the VFR is on the left hand side of the engine, mounted to the inside of the alternator cover. This means it is submerged in the engine oil. (I’m guessing that most four stroke motorcycles would be the same). So, to replace the stator, you will also need a new alternator gasket and an oil filter (as you end up doing an oil change).

As usual, you should read my disclaimer, if you feel inspired to give this work a go. As a comparison, this is probably the trickiest procedure that I have blogged about. – You have been warned!

Start by removing the two side cowlings and the connecting front piece from the bike. These require a 5mm Allen key and patience as you struggle with the plastic clips that go together easily the first time and then deteriorate, get jammed up with road grime and go brittle with time.

Once the panels are removed, warm the bike up for a minute or two. The idea is to not make the engine too hot to work on, just to raise the temperature of the oil enough to reduce its viscosity. Stop the bike, do what you need to do to stop yourself from absent mindedly starting it with no oil and remove the oil drain plug.
Draining the oil

While the oil is draining into an appropriate receptacle, unbolt the radiator overflow bottle. The workshop manual suggests removing it all together, but I found that by using a zip tie, I was able to access the alternator cover without needing to drain it or disconnect the hoses.

Moving overflow bottle away from alternator cover

The astute reader may have noticed by now that while the stator is located on the left side of the bike, its connector is plugged in on the right hand side. This means the wiring is threaded through, from one side to the other. Pulling the old cable out is always going to be easier than threading the new one through… The workshop manual instructs you to remove the fuel tank, airbox and the throttle bodies to gain access to the wires. Removing all these parts would undoubtedly make routing the new stator cable easier, at the cost of making the overall job much harder! Instead, I tied a piece of string to the stator’s plug and carefully pulled the cable through the bike, such that the whole wire ended up hanging on the left side of the bike. The string is then left in place, to guide the new stator wiring back through.

Wrong Focus!

Once the wiring is clear of the bike, the bolts holding the alternator cover in place can be removed. Even once they are removed, the alternator cover is held in position by the strong magnets that generate the current as they spin around the coils of the stator. There is a lug on the alternator cover that, with a bar and mallet, I was able to tap on the back of to break the magnetic seal.

Burnt out stator

Despite what the workshop manual suggested, I found that the stator on my bike was held in place with Allen key bolts, rather than Torx head bolts. I have no idea whether this is common or not, but it meant my purchase of the torx head keys was unnecessary… One day I will have a use for them… You will probably find that the bolts holding the stator in place are on pretty firmly, so take care not to do this :-). If I had any good suggestions on how to avoid sudden knuckle/cover contact I would not have injured myself, so good luck with that!

Carefully note the positioning of the stator so that you can correctly orientate the new one and then remove the dud piece.
While you have the stator removed, take some time to remove as much of the old gasket as possible without gouging the alternator cover. Remember that the cover holds the engine oil inside, so a good smooth surface is important to avoid leaks.


Once you are happy with your handiwork, use the dowel pins to hold the gasket correctly aligned and refit the cover. As per the workshop manual, the cover should get some gasket sealer in certain parts. Remember that the magnets in the generator will pull the cover on with a certain amount of force, so be careful to position wiring and hoses clear of its flight path!

Reassembly wasn’t quite as straight forward as I hoped. Although the string helped, I still ended up lifting the tank and airbox, as the wiring connector fouled on various bits and pieces. Still, I managed to avoid removing the throttle bodies with my mad-cap idea… For details on removing the tank and airbox, see this post from when the bike was newer and cleaner.

Fitting the oil filter is one of those few exceptions where I used my torque wrench. I am pretty good at not striping bolt threads – working on the 24 year old RGV teaches you to be careful with such matters, but the oil filter was too critical (and fragile looking) to warrant a careless approach.

The only other point to draw to attention is with refilling the bike with oil. Once the engine turns over, oil will be dragged around all the places it had drained from, so after a quick run, let it settle and recheck the oil level. You may find it needs more to reach the desired level.

Once I was happy that I had put everything back together properly, it was time to try the charging circuit. I didn’t have enough hands to take a photo when holding the engine at 5000 RPM, but as we can see, there was a healthy 13.80 volts at idle.


Problem solved!!

Taking charge of the situation

Recently, my trusty steed (the VFR) has been anything but “trusty”. After a great ride through the Victorian hills it abruptly decided not to start. The all too familiar “chugging starter motor accompanied with the dash going dim followed by the clock resetting to 1:00am” of a flat battery greeted me. Given that the battery would be approaching the five year mark, I thought nothing of it and replaced it.

Five engine restarts with the new battery later and I was left staring in disbelief as the dash again went dim and the clock went back to 1:00am. Sidenote: Why is it that Honda insists on making the clock so impossible to set without uttering profanities? When pressing two buttons at the same time means AT EXACTLY THE SAME TIME!

After coaxing the battery back in to a reasonable state with a charger it was time to whip out the multimeter and perform some testing. The simplest test from the workshop manual consists of running the engine at 5000RPM with the lights on high beam and measuring the voltage across the battery terminals. The manual rather cryptically suggests that the charging voltage should be more than the battery voltage “at rest” and less than 15.5 volts. Given that it was slightly lower than before commencing the test, it seemed a fairly safe bet that the bike was no longer charging the battery.

Back in the day, “they” used to say that Hondas were notorious for cooking regulator/rectifiers. My first Honda (the mighty Super-blackbird – the bike that was ever so briefly the fastest production model motorcycle on the planet) certainly managed to break this component and overcharge the battery in the process. It appears that Honda beefed up this component as my next Honda (a 929 Fireblade) burnt out the stator coil. It was looking like the VFR had suffered a similar fate.

The workshop manual specifies various tests – measuring resistance and testing continuity of various connections to determine the faulty part in the charging circuit. On the right hand side of the motorbike is the connector from the stator into the charging circuit. It is described as being a “3P natural connector” although “white” seems to be an equally suitable term…


According to the manual, there should be no continuity between any of the three yellow wires (in the plug) and ground. The multimeter revealed that two of the three wires did indeed have continuity to ground and hence I had found the problem! As for what to do about it, well that is a story for another time.


I recently completed my latest motorcycle touring holiday. I travelled more than 4000 kilometres (2500 miles) over the course of two weeks and two days, to attend the Philip Island MotoGP. The VFR800 is definitely a more comfortable touring bike than the CBR929 Fireblade that I made the trip on last time, but it is some way short of a Goldwing in terms of touring comfort. Fortuitously, a friend of mine lent me his Airhawk seat for the journey.

I am always sceptical of miracle motorcycle products. I have seen instances where some one’s praise of a product is little more than them trying to justify the purchase price of whatever product they are expousing the virtues of. In the past I have purchased and used sheep-skin seat covers for some of my motorcycles. To claim they make no difference, would be doing them an injustice. But, when you are riding a motorcycle for long periods of time, multiple days in a row, their improved comfort is short lived.

My suspicions that the Airhawk would be no different were proven to be wrong. I was more than a little amazed by the improvement in comfort the seat provided. Small interlinked air-pockets help evenly distribute the pressure. Because the pockets are interlinked, air is free to move between the various pockets. An unexpected benefit is the extra shock-absorbtion the seat provides. Hit a big pothole and you don’t get the proverbial boot up the backside. On an extended ride, this fact alone makes for a more pleasant journey.

I did eventually feel discomfort on the bike, riding up the Hume Highway on my return home. I don’t know if it was due to the boredom of the ride, but (rather unscientifically) I feel that some of the discomfort was caused by a lack of movement needed to ride in a straight line. Riding the Hume, is largely about sitting still and holding on. Not needing to perform gear changes or large steering input meant I was stuck in the one position for long periods of time.

Like all good (and many not-so-good) web reviews, I should really summarise my experience with the Airhawk seat with a pros and cons list.


  • shock absorbtion
  • greatly improved comfort
  • adjustable inflation to allow for different rider weights
  • weatherproof and quick drying time when compared to sheepskins


  • reduces the rider's feel for grip levels in corners
  • over and under inflation limits the effectiveness and improved comfort

In an unusual "neutral" category:

  • it changes the rider geometry on the bike

For me, the change in geometry was not substantial enough to be problematic. I was concerned about the increased weight placed on my wrists made by effectively raising the seat height. It is only a small change in geometry, but even small changes alter how the bike feels. For vertically challenged riders, it may also make the reach to the ground just a little more unnerving. Of course, not being a journalist and trying a formal review, I missed the obvious action of measuring just how much height was gained by using the seat. At a guess, I would say between 15-25 mm of increased seat height can be expected.

Given that I lent the seat, I will not give a subjective value-for-money opinion on the product. However, if I don't find one in my Christmas stocking this year, it will go on the list of things to purchase for myself!

Has Honda got the wrong idea?

I watched a YouTube video about an option on Honda’s forthcoming “VFR1200”.  The option features a computer controlled double clutch gearbox, eliminating the need for a hand-operated clutch and gear selection foot pedal.  I know precious little about the technology, but at face value, it seems similar to systems fitted to up-market sports cars.  Jeremy Clarkson and I would probably not see eye-to-eye on a great number of things.  I am a motorcycle nut, and he isn’t. (to put it mildly).  However, he has a hatred of “flappy-paddle gearboxes” which I think I understand.

Watching the video, it was amazing to see the seemless nature with which the computer controlled gearbox changed gears. This was most notable if the final scenes when the video focused on the “attitude” of the bike.  The degree to which the rear of the motorcycle squatted during the acceleration run barely changed through the gear shifts.  This was most impressive when compared with the conventional manual transmission bike*.  Despite this, I cannot help feel that Honda have solved a problem that no-one else was aware even existed.

There are times that I have made a complete hash of changing gears whilst riding a bike.  Sometimes I have found a false neutral and sent the revs skyward when the engine encountered no resistance. (I find this almost as embarrassing as sneezing in your helmet when stopped at traffic lights…)  Sometimes I have discovered I am already in first gear when down-shifting, or top gear when up-shifting.  Occasionally, I’ve missed the gear lever altogether (although I’m still not sure how).  There are also times when my arm has ached from constantly needing to pull in the clutch when riding in heavy traffic.  None of these factors make me want an “automatic” transmission on a motorbike.

Part of the fun of riding a motorcycle is the connection between the rider and the machine.  Just because the machine could do something better than I could, is not a reason to let it do it.  I am sure that some people will appreciate not having to use a clutch in heavy traffic or the consistent smooth gear changes the system promises.  But it is not the sort of marketing hype that entices me.

 Technology can be enticing.  A few years ago I had the opportunity to test a BMW K1200s with the Electronic Suspension Adjustment (ESA) system fitted.  The system was interesting and seemingly worthwhile.  The benefits of on-the-move suspension adjustments were noticeable in the real world.  Here was a new technology that gave an increased involvement with riding the motorcycle.  Few people take the time to sort out their suspension of their motorcycle despite the benefits of doing so.  Here was a computer-controlled system that “did the hard part for you” and left the fine-tuning up to you.  At a press of a button, you could soften the suspension for “comfort” or firm it up for “sport” riding.

So, on one hand you have Honda making the process of riding easier by removing some of the tasks you need to perform. This has the impression of making you more disconnected from the experience.  On the other hand you have BMW making it easier for you to become more involved with the riding experience. 

How much an automatic gearbox disconnects you from the experience of riding the bike is going to be subjective.  I am not above being wrong and if the opportunity arises to try the system, I shall – but it is not the sort of technology that excites me.

* I couldn’t help get the feeling that the gear changes performed on the bike with the conventional gearbox were exaggerated by the rider…


Balancing the Starter Valves on a VTec VFR

Last time around, I built a manometer, with which I could balance the starter valves on the VFR. The current model VFR has a chequered history with respect to fuelling issues. My pet peeve, is with the abrupt nature that the throttle travel starts. From closed, rolling on the throttle results in a “nothing… still nothing… BANG WE’RE ON” feeling from the engine. I’ll save some of you a lot of reading: After performing the starter-valve balancing procedure, the bike still has this light-switch style throttle. Subjectively, maybe the bike is a little better, but I wouldn’t dismiss “wishful thinking” may be biasing my opinion.

EDIT: After much consideration, I have revised my opinion. Rolling on the throttle from “closed” is still tricky to do smoothly, but it has become possible since performing this operation. I leave my original statement in the blog entry, but my revised statement is that this operation has definitely helped my bike and made for a more pleasurable riding experience.

Before I begin my walkthrough, there are several things I need to point out.

  • I am not a mechanic: Read my disclaimer.

  • When referring to the bike’s left or right, front or back, the directions will be orientated as they would be if you were sitting on the bike riding it.

  • I described fitting after market exhausts as “easy”. I would describe this job as moderately tricky. This walk-through is more about putting pictures to the procedure outlined in the workshop manual. There are risks associated with performing this task and if you never got past the disassembly / reassembly of some old equipment without having left-over pieces then I recommend you don’t try this one.

  • Balancing the starter valves should be done with the engine running at normal operating temperature. (presumably this is so the bike isn’t fast idling.) From experience I can tell you that it is possible to remove the parts of the bike required without burning fingers, or alternatively run the bike to warm it up when it is partially disassembled.

To get to the starter-valves, you need to lift the tank and remove the airbox.

The tank is hinged at the rear and can be lifted once the two 8mm bolts are removed from the front of the tank.

Tank bolts

The bike toolkit comes with a C-spanner and handle precisely the right length to get “maximum lift” from the fuel tank and despite its appearances is quite steady when in place. The tank has a “restraining wire” that prevents it being lifted too far. Pay heed and don’t attempt to lift it higher!

Once properly positioned, carefully remove the Number 15 vacuum hose from the variable air-intake diaphragm on top of the airbox. (i.e. make sure you don’t tear the rubber hose!)

removing vacuum hose

The airbox is in two halves (upper and lower). There are seven Philips head screws to be undone to remove the top half of the airbox.

Airbox screwAirbox screw

Screw locations

Once the top half of the airbox has been removed, the air-filter will lift straight out.

Remove the four air funnels in the airbox by undoing the two Philips head screws on each funnel.

Air funnels

On the left side, remove the PAIR air hose from (near) the rear of the airbox.

PAIR hose

Slightly lift the airbox and disconnect the white IAT sensor.

IAT sensor connector

The PAIR solenoid valve is attached to the rear of the airbox via a rubber strap. Slide this off the prong on the airbox.

The other end of the PAIR hoses connect to the cylinder head covers. These should be blocked off for performing the starter valve synchronisation. Rubber stoppers or even a bunched-up clean rag should be sufficient to do this.

PAIR reed valve cover

On the right side, remove the PAIR air hose from the rear of the airbox, the electrical connector from the MAP sensor and the vacuum line on the bottom of the MAP sensor.

MAP sensor and PAIR hose

About half way along the right side of the airbox is the bypass control solenoid valve. Disconnect the grey connector from the bypass control solenoid valve and the number 12 vacuum line from the one-way valve.

Grey connector

You should then be able to lift the bottom of the airbox off the bike.

Undo the MAP sensor from the airbox (held in place by a Philips head screw) and reconnect the vacuum hose and electrical connector. It wasn’t possible to access the screw that holds the MAP sensor in place until the airbox had been removed.

Now you’re ready to connect your manometer.

The four cylinder vacuum hoses are connected to a 5-way adapter. (The fifth line is the other end of the map sensor vacuum line)

5 way connector

Disconnect the four lines from the adapter and plug in your manometer. It’s not really important which hose connects to which tube, as long as it’s logical to you! You will need to know which vacuum line is attached to which manometer tube.

All hooked up!

The moment of truth starts here! With the bike in neutral and on the centre stand start the engine and cross your fingers! Well, actually, don’t cross your fingers – because you may need to turn the bike off in a hurry if something has gone wrong and oil starts travelling up the manometer tubing at an alarming rate. Note that the “FI” light on the dashboard will be showing. At a guess, this is because the ECU has detected that some of the sensors are “missing” / disconnected or are giving funny readings. This is hardly surprising given the amount of stuff we’ve disconnected.

There are three brass 7mm adjusters, allowing you to adjust the vacuum generated by each cylinder relative to the fourth cylinder. The aim is to have the same amount of suction on each cylinder, which means you will have even amounts of oil in each tube of the manometer.


The adjusters are on a spring-loaded ratchet style arrangement. That is, they turn in “clicks”. It’s a confined space and difficult to get tools in there neatly. Assuming you don’t have a tool that neatly fits in the area provided, the way I see it, you have three choices:

  1. You can “unload” the ratchet making the adjusters free to turn by hand, by pulling the brass adjuster “out”. (That is: pulling the adjuster away from the throttle body assembly) The problem with this method is that whilst the adjuster is “out” you have altered the amount of vacuum generated on that cylinder hose.

  2. You can use an open ended spanner. This works okay, but you are limited as to how far you can adjust each cylinder to around two clicks before you need to take the spanner off and reposition. If the starter-valves are a long way off being balanced, this can be a frustrating experience.

  3. You can use a socket on a T-bar that doesn’t sit squarely on the adjuster. Normally I wouldn’t condone such a practice as it is a great way of rounding off the edges of a nut. This is especially true seeing as though the adjuster is made from brass (and therefore very soft). However, in this case you don’t need to exert much force to overcome the “click”. As long as you are careful this technique works well.

Adjusting the adjuster!

Turning the adjusters changes the amount of air that can be drawn through two holes on the throttle body. The more the air is drawn through these holes, the less the suction will be on the cylinder vacuum hose.

Air hole

Turning the adjuster clockwise opens the air hole and thereby reduces the suction in the vacuum hose. (the oil in the manometer will drop). Turning the adjuster in the opposite direction causes the oil in the manometer tube to rise.

Now it’s just a matter of patience until you get the oil-levels in the manometer as even as possible.

There are a few tips I picked up along the way:

  • The procedure should be done with the engine running at 1200rpm. Use the throttle stop screw knob (on the right side) as necessary to keep the revs consistent. (The starter-valve adjustment can affect the idle speed).

  • When you first connect the lines, if one of the adjusters is a long way off correct, oil may drain quickly out of one of the manometer tubes. If the tube empties completely, air will be drawn into the manometer and this is a “bad thing”. To quickly force oil to be drawn back up the manometer tube, you can cover the air holes with your finger.

  • The workshop manual has the usual line of running the engine in a well ventilated area. They weren’t kidding! Leaning over the engine with it running exposes you to far more exhaust gasses than you normally get. Don’t take the suggestion of “well ventilated” lightly!

  • Running the bike at idle is not sufficient to recharge the battery. The Australian model VFR does not have a headlight switch. (they are “hard-wired” on whenever the engine is running). If you can’t turn off your headlights, it is a wise idea to disconnect them so that they are not drawing current from the battery. Depending on how long you run the bike for, or if you need to stop and restart the bike a few times, the process can be quite taxing on your battery.

The workshop manual also indicates you should reset the ECU after balancing the starter-valves. The (correct) reassembly of the bike will be sufficient to prevent the FI light from remaining on, but I can only guess that it keeps some “memory” of the sensors having been disconnected.

And that’s about it! As the manual states: “Reassemble in the reverse order”.