Tag Archives: mechanics

Who needs a battery anyway?

Having built my “under-seat” tray to hold the CDI and SAPC units, all that was left to do, was to place the battery somewhere.  Part of the problem of owning a track bike, is that it is unlikely to see regular enough usage to keep a standard battery charged.  Standard lead-acid batteries are heavy too.  If you are used to seeing a car battery, motorcycle batteries do look miniature by comparison, but my new tray did not allow room for the standard RGV battery.

The VJ21 and VJ22 model RGVs were fitted with a kick-start system.  Given that there is no electric start on this bike and that is devoid of lights and indicators, the only real function of the battery is to power the CDI and SAPC units and spark plug coils.  Like most engines, an “electrical generator” of sorts uses the spinning of the crankshaft to recharge the battery.

Some racing bikes run a total-loss system.  The charging system causes a drag on the engine.  The more current you try and draw from it, the more the drag and the bigger the performance hit will be on the engine.  A total-loss system will not recharge your battery as the engine runs. By doing so, less load is put on the engine, leaving more power to actually propel the bike.  Unless you are at the elite level of the sport, it is unlikely that having a total-loss electrical system is worth the trouble of recharging the battery after every race.

Given that the generator provides electrical power, the battery becomes superfluous to requirements. The regulator/rectifier and AC generator of the RGV is sufficient to power the electrics of the bike while it is running, and your leg (and kick-start) is enough to provide the initial power to start the bike.  A “battery eliminator” can be built and substituted for the regular battery, saving weight, space and the “oh-no” moment, caused by a battery that has gone flat through lack of use.
Although commercially available “battery eliminators” can be purchased, “Mick” on the currently out of action Yamaha-rd forum  wrote a succinct post on how to build one:

You need;
3 x 4700µF 25V electrolytic capacitors
1 x 500ohm resistor
some solder
a soldering iron
source of power for the soldering iron
cup of tea
decent music

OK, solder all of the components together in parallel; that is +ve terminal to +ve terminal. This is important. The resistor can go in any way round, but they must all be connected in parallel with each other.

Remove the battery from your bike.
Connect the eliminator up the right way round (+ve end to +ve connection on the loom)
Switch the bike on (note: the PVs won’t move until the engine’s running)
Start ‘er up.
Ride the bike, and enjoy the feeling of having lost 2.5kg of ugly fat.


How hard could it be?  There was a discrepancy between the commercially available, and Mick’s battery eliminator.  Mick suggested a total of 14100 micro-farads, whilst the Zeeltronic schematic had 30000 micro-farads. (and a different amount of resistance).  From my limited understanding, the capacitance allows a good way to smooth out the voltage provided across the unit, whilst the resistance provides the regulator/rectifier with a workload.  Without this load, the regulator/rectifier would overheat.  (Feel free to correct me here)

Battery Eliminator PartsI bought the components from Futurlec.  Shortly after I ordered the parts, I read the horror stories from “customer review” websites.  Put simply, they grossly understate shipping times and I am not convinced they ship your order when they claim to.  They also allow normal mail shipping of their products and hence they cannot be tracked on-line.  This further reduced the transparency of their operation.  The parts did arrive after four weeks.  Their website made me believe it should have only taken two…  In days before Internet shopping and on-line tracking of parcels, I would not have thought twice about the length of time it took for my order to arrive.  These days though, it is a different story.

Once I knew how large the capacitors were, I purchased some cabling and a zippy box of sufficient size from the local Dick Smith Electronics shop.  Then all I was missing was the cup of tea and some decent music!

Battery Eliminator Circuit BoardRather than use a breadboard, I drilled holes in a piece of Perspex to hold the wiring in place and rubber mounted the board inside the zippy-box in an attempt to shield the components from solder loosening vibrations.  Once I had finished construction and fitted it to the bike, I tried to start the bike… At 30,000 micro-farads, I could not generate a spark.  In the end, I removed one of the capacitors (reducing the overall capacitance to 20,000 µF) and had instant success!  (Yay!)

Given that my de-soldering technique is even rougher than my soldering technique, I didn’t bother providing photographs of the final product.
For those of you tempted to try building your own battery eliminator, I have ended up with the following configuration:

  • 2 x 10,000 µF 25V electrolytic capacitors
  • 1 x 1000ohm resistor (5W)

So now you have three different sets of figures to guess at!  Good luck!

Battery Eliminator wired up.Battery Eliminator in boxBattery Eliminator vs. Battery
(Edit: Pictures added)

RGV Update

“Good news everyone!”  The RGV’s engine officially works.  The reinstallation of the engine took far longer than planned.  That was due to a combination of intentional stalling to get the budget back on track, unplanned extra work due to faults discovered along the way and limited spare time.

When I went to install the engine back in the frame, I discovered a hairline crack in the engine cradle.  Although the engine has rubber mounts reducing the amount of vibration transferred to the frame, common sense dictated that I should not ignore such an obvious weak point.  A quick trip to a local aluminium welder had that problem sorted out.

During this time, I took the opportunity to superficially tidy up the expansion chambers.  (exhaust pipes)  I say “superficially”, as I made no attempt to reduce the carbon build up that is surely deposited on their insides.  Instead, I sanded back the existing layers of paint, removed as much of the surface rust as possible, treated the remaining rust with a “rust converter” and treated the pipes to a fresh paint job with heatproof paint.  Whilst being a “far from perfect” job, it should give the pipes a bit more protection against the elements.

The reinstallation of the engine, exhausts and cooling system went remarkably smoothly, given that I do not have a workshop manual.  I have yet to buy myself a workshop manual for the bike.  This is largely due to the fact that I used to have one and they are not cheap.  I cannot quite bring myself to buying a new one.  These days, “bootleg” PDF versions are available on the internet.  I have found the PDF version of the RGV manual to be an incomplete series of bad quality scanned in images.  Still, using this and referring back to photos I took of the bike at the beginning of the year meant I did not end up with “bits left over”.

Once it was back in one piece, half a litre of fuel and the battery were “borrowed” from the VFR, and I was able to fire the bike back into life quite easily.  The “build” itself still has a fair way to go.  The high-level short list comprises of:

  • Replacing the brake lines and servicing the brake calipers
  • Front fork rebuild or replace (to be decided based on pricing)
  • Replacing various bits and pieces that are worn out. (chain and sprockets / clutch lever and cable / etc)
  • Fitting the new bodywork.  But that’s a story for another time.
  • Furlough Day II

    On my last Furlough day, I took the opportunity to go for a week-day ride.  The weather, on that occasion, was at the “turning point”.  Up until then, we had been enjoying spectacular crisp clear winter days – the sort that makes this time of year the best time to ride in.  The day after my day off, it rained…  And rained…  And rained…  In fact, Brisbane had the most rain in a 24-hour period since 1974.  The day after, it rained almost as much, again!  As such the weather was “rolling-in” on my ride and I was lucky to only traverse a small amount of wet roads and even less rainy weather.
    For this Furlough day, I decided I would work on the RGV. The weather was not going to intrude on me this time!  (It was a good job I had planned an indoor activity as it did end up raining all day)  Everyday life interfered a bit with progress on the bike and as such I only really got to spend around three hours tinkering with the bike, on the day.
    I took the opportunity to replace the various Philips head screws that I removed with Allen key-headed bolts.  It seems to be a fairly standard technique when restoring these bikes and will hopefully assist in easier removal next time I am servicing the parts.   The nuts on the cylinder head bolts were also badly worn – so I replaced these with new stainless steel ones.  It had been mentioned on the forums that the two dissimilar metals would lead to galvanic corrosion.  I am no metallurgical expert, but it was also mentioned that copper washers could be used to avoid this problem.  So I bought and used some of them as well!  I highly recommend going to a specialist fasteners shop when you need to buy nuts and bolts.  They tend to sell higher quality parts, you can get the exact numbers of what you need and they do not come with the ludicrous price mark-up that the generic hardware shops have for “packs of ten”.  (As an added bonus, you will talk to someone who knows what they are on about and can probably offer you some advice!)
    The RGV engines have “powervalves”.  The purpose of the powervalve is to restrict the flow of gases exiting the combustion chamber at low engine speeds.  At higher revs, they “open” allowing more gas to escape.  A detailed description of what they do and why is probably worthy of its own blog entry, but the reason I mention them is that they are notoriously weak on the RGV.  If the powervalve breaks, it can drop into the cylinder barrel, where it tends to be collected by a piston travelling at upwards of 12000 RPM.  The results can be quite catastrophic.
    Whilst I had the engine apart, I took the opportunity to inspect the powervalves (there are four of them) and discovered one looked suspiciously like it was on the path to failure.  So I was able to replace the faulty part and clean them up.  Powervalve inspection is possible to do with the engine in place, but seeing as though I had it removed, it made the task far less onerous.
    The cylinder barrels themselves appeared to be in good shape – there was no plating missing or damaged, so I installed the new pistons and rings and put the engine back together.
    The next task is to reinstall the engine in the frame, check / set the powervalve adjustments and  refit the cooling and exhaust systems. Then, I’ll feel like I am getting somewhere with the project!