Franken 550

Part 2/2:
Forks installed. It looks fantastic but the LTD seat, ignition cover and alternator cover need some red to tie them in to the color scheme. Tailight needs to go as well. But those can be done later. Paint needs to be touched up, but again, at a later time.


I plan to finish the last few things (clean tank, install exhaust, install front caliper) and start it up today. The bad thing is that i'm already dreaming of the next build! i'm thinking another kz550 frame, newer water cooled 1200 motor, forks/swingarm swap.

Aggghhh this forum. It wouldn't let me post and kept deleting the image links in the post... im guessing there's a picture limit, but it didn't give any errors!

Nice job!
I saw you mentioned the screws in the timing/pickup plate. Some should be brass (non-magnetic) and some should be steel.
They are actually JIS screws (as opposed to philips).
This link shows where the brass ones and steel ones go.
s3.amazonaws.com/gpzweb/Ignition/PickupA.../PickupAndRotor.html

Also, I saw you mentioned capacitor. If the bike is to be wired permanently for a capacitor instead of a battery, there are a couple things you may want to do, or maybe you already did them. For one, the headlight and any other lights should be wired so you can turn them off. Without it, it will be much harder to start with the capacitor. And if your regulator/rectifier has a brown wire, you should wire that to the output wire of the regulator/rectifier to protect the capacitor. Some reg/recs don't have a brown wire in which case you don't have to worry about it.

Ah good point on the screws, i do believe the outer ones are steel, but i will double check. and haha yea, JIS, sorry, i still hate them as half of them are stripped from the previous owner!

My start switch box thing on the handle bars does have the slot for a headlight on/off switch but is blocked off due to gov regulations...Wish i could find one of these switches

Ill check into that brown wire (which i found out to be the battery voltage sense line)

I did get it running last night!


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Yes, the brown wire is the sense line. In normal wiring, if you shut off the key, the sense line gets disconnected. If the motor continues to turn, not actually firing, but turning as if you are coasting down hill etc, the alternator is still putting out power, but the regulator can't regulate since the sense line has been disconnected. Additionally, there won't be any of the alternator power being used for lights or ignition since the key is off. This will cause the reg/rec to pump uncontrolled, full power into the capacitor, which may then reach much higher voltages than it was designed to. A battery can handle this short-term abuse because the excess power will dissipate as current flows through the battery. But capacitors cannot flow DC current indefinitely, so their voltage just increases. If it exceeds the voltage rating of the cap, it will short. The simple solution is to wire the sense line permanently to the output so the regulator will always regulate.

The brass screws are used because if magnetic screws are used, they will weaken the effect of the magnets in the pickups. This can cause a hard-to-start situation in some cases. (Some sets of magnets were weaker than others in the Kz pickups).

For going battery-less, I use a relay to automatically turn the lights off when the bike shuts off. Then I use the starter button as a trigger to turn the lights on after the motor is running. The relay is self-holding so it shuts off when the motor stops.

I have to bumpstart my batteryless 550. I do sometimes wish it had a kicker. Gravel parking lots mean I will be pushing if it shuts off.

Hmmm, i feel like it wouldn't be an issue 99% of the time as the engine would have to be turning with the ignition off, which would be rare, but maybe i should do it to be safe. Why would you coast down hill with the motor off? you'd still be pulling in fuel.

The cap battery was totally dead and as i first attempted to start it last night. kicking would keep the dash lights on but didnt have enough juice for the headlight or the ignition coils so I had to charge the caps a bit and then it kicked right over. The aftermarket LED headlight i put in acts kinda weird in that it doesn't seem to turn on till the bike is running. I'm thinking it has some sort of smart circuitry.

I might just keep a lipo around to quickly jump the caps up to 12v if it ever dies. I went full LED so i have little parasitic draw.

Now if it didnt start snowing last night.... gah!

Some people fool around with the kill switch in tunnels etc to create a big backfire. And other tom-foolery.
It can also happen if the throttle were to get stuck and the motor red-lined and you kill the ignition. The alternator would still be putting out a lot of power as the motor slowed to a halt.

Capacitors will drain pretty much instantly. They do not hold any significant charge compared to a real battery. It's the alternator that provides all of the energy. In one kick, the alternator/rectifier has to fully charge the empty capacitor and then give power to the ignition. It can do it easily if the kick is fast enough, but not if there are lights on. Lights act like a dead-short until the filaments heat up and start making light.

The capacitors are really just acting like a filter so the regulator can regulate properly. They are not meant to be a power source.

The portion of the kick required to charge the capacitor will vary depending on the size of the capacitor. If the cap is too big, it might not work, but it would have to be really big for that to happen. You can always add a little 9-volt battery to charge the cap through a diode for safety. But I haven't found that to be necessary.

I definitely have too large of a capacitor bank. I sized it for the 550 when I still had a starter. Its rated at 16v Max and 83 farrad. A bit of math and that's about a 330mAh battery.

I can't take any cells out because they're 2.7v cells wired in series to be safe at these voltages.... I wonder what the ideal size is for a motorcycle with LEDs and kickstart only...

Edit: hmm actually I could probably measure the power usage of the bike while running off of a battery and use that to find the ideal size.

Saablord wrote: I definitely have too large of a capacitor bank. I sized it for the 550 when I still had a starter. Its rated at 16v Max and 83 farrad. A bit of math and that's about a 330mAh battery.

I can't take any cells out because they're 2.7v cells wired in series to be safe at these voltages.... I wonder what the ideal size is for a motorcycle with LEDs and kickstart only...

Edit: hmm actually I could probably measure the power usage of the bike while running off of a battery and use that to find the ideal size.

I guess I don't know what you are really using. A simple capacitor doesn't have cells. All you should need is a single 50v capacitor in the range of 5000 to 10,000 micro-farad. 83 farads would be 10,000 times more than you would need. The voltage rating on a capacitor is not the voltage a capacitor provides, but is the maximum it can safely handle. Because of possible over-voltage issues and because it's easy to get caps in higher voltages, 50v to 75v makes for a good safety margin over the expected 14v it will likely handle.

The capacitor typically, when used in our bikes, is not an energy storage device. It is a ripple filter, like any other ripple filter on a classic power supply. The energy comes from the alternator in pulses. The capacitor just filters the pulses so the regulator can regulate it properly.

Here's the one on my bike. I actually installed two, but only one is connected. The other is a spare. I think they are either 5000 or 6000 micro-farad (uf). I installed these 10 years ago and have never had to use the spare. The bike sits in an unheated garage, in subzero temps during the winter. These are cheap (relative to batteries) industrial capacitors, around $20 new, but are good quality ones. I think the light blue one is a Mallory made in the 1980's or 1990's and were used 10 to 20 years before I installed them in the bike.



If your 650 has a 3-phase alternator (3-yellow wires) then you would probably use about the same size cap as I did.
If it's a single-phase (2 yellow wire), then you might be able to use that size or may want to get a slightly bigger one. Maybe 8000 to 10,000 uF.

Something like this:
www.digikey.com/product-detail/en/vishay.../4334PHBK-ND/2258685

Haha, sorry, cells was the wrong term. I am using this:


Capacitors in series you add voltage and 1/(1/c+1/c.....) capacitance. so i have a safe limit of 2.7v*6 =16.2v. and capacitance of 1/(6*1/500F) =83F. I know this is large and at this point it is more like a battery. I measured the voltage the next day after running it previously and the voltage was 10.5v. This is more of a car battery replacement and i bought this to handle the 550 with a starter. Ill probably eventually buy a starter for the 650.

The estimation for the equivalent battery size is based on capacitors being a linear device whereas they are clearly not as energy stored decreases significantly as voltage drops. Also, micro farad is 10^-3 farad so a 5000 to 10000uF are 5 and 10 F. So they are 16 or 8 times smaller than mine.

Again, sorry for the confusion.


Anyways! The bike! I flushed the water out of the tank (cleaned it one last time before install) and carbs so that the damn thing would actually run right. It also started a bit easier when the carbs were actually delivering a combustible liquid, haha. The tach is still stuck but i think that has something to do with the sub freezing temps and some lube would help.



Some videos:
walkaround
some revs

Dang, I freaking love these noises.

Saablord wrote: H
The estimation for the equivalent battery size is based on capacitors being a linear device whereas they are clearly not as energy stored decreases significantly as voltage drops. Also, micro farad is 10^-3 farad so a 5000 to 10000uF are 5 and 10 F. So they are 16 or 8 times smaller than mine.
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Micro-farad is actually 10^-6, farad not 10^-3 farad. 5000 uF is .005 farad.

Saablord wrote: H
The estimation for the equivalent battery size is based on capacitors being a linear device whereas they are clearly not as energy stored decreases significantly as voltage drops. Also, micro farad is 10^-3 farad so a 5000 to 10000uF are 5 and 10 F. So they are 16 or 8 times smaller than mine.
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Micro-farad is actually 10^-6 farad not 10^-3 farad. Thus 5000 uF is .005 farad.

The bike sounds great!

Ah crap, my bad, brain fart.

I didn't get all the water in the tank apparently though so its drying out for a while. Now I wait for ride-able street conditions