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Discussion Starter #1 (Edited)
I'm needing to replace my dead battery now, and I've been hung up on kickstart engines quite a lot since I got into motorcycles, for the rider to machine connection, potential weight savings, nostalgia, etc. I dropped my '77 GS750 from 552 lbs wet weight now to 500lbs, & more weight savings would nicely offset the hefty crankcase contents of these overbuilt engines. 16-17 lbs weight savings deleting the battery, starter, and starter gears on my dieting large-cc corner carving machine would be excellent!

Battery Eliminator Oregon Motorcycle Parts says that much less than a 22,000uf capacitor is no good for trying to smooth out the gaps in the stator pulses on ignition startup & idle on a smaller or 2 cylinder engine., & are working on a 40-60,000uF cap kit for 4 cylinder bikes.

I see very large 22,000uf and larger caps in the 35 to 70 volt current handling capability for $10-$40 on ebay, and I thought about running two of those in parallel in order to have more power and have 2 in case one blew, so for $40-ish I could have 40,000+uF of electrical ignition assist in kickstarting, and keeping the lights from flickering at idle (plus no battery/starter weight).


Downside I hear is that the caps (maybe just smaller ones?) are bad at soaking up high revving voltage surges from your charging system at it's peak output, and you blow light bulbs much more often. The other downside to this is that if I run out of gas (or the bike breaks down) at night in the hills or in low lit areas where there may be traffic, I am totally without lights as soon as I pull in the clutch or the bike comes to a stop. I go camping with the bike, so lights with the battery off would be nice.




Ballistic and Shorai have been making Lithium-Iron Phosphate batteries (similar to Li-Ion) for motorcycles that cost quite a lot, are a little smaller, and weigh SUBSTANTIALLY LESS. Comparison: Shorai Motorcycle Battery Review vs. Ballistic Motorcycle Battery Comparison Review - webBikeWorld
How much power/amp-hours do I really need to adequately power the Dyna-S ignition and one or two indicator lamp bulbs when kickstarting?
I am looking at tiny 4 cell Ballistic batteries, with no starter motor draw, how small can I go? A 50cc-scooter-spec 4 cell battery should do it, right? May be able to afford one of those, and have some quick headlight power still after the engine is off.



Ballistic 4 cell battery, this thing might be the ticket for a kickstart only, what do you guys think?:
Batteries - Ballistic Performance Components
Ballistic 100-009 $58 ebay shipped (2"x2"x3.25"), or the slightly larger Ballistic 100-010 (2.5"x2.5"x4.25" 2.3 amp/hours) $87 shipped.


CAPACITOR(S):
+slightly lighter than LiFePO4 battery
+much cheaper (~$30-60 ebay)
+substantially smaller than lead acid battery
-may burn out light bulbs more frequently on higher rev's (inability to act as a large cushion for charging system spikes)
-no lights when engine off, no lights when bike dies from no gas or mechanical issues (danger in traffic)

SMALL LIGHTWEIGHT LI-IRON-PHOS BATTERY:
-substantially more cost, $100+
-does not tolerate charging more than 14.4 volts, will fail
-does not tolerate running it dead below 9 volts, battery is shot if you discharge it less than 6 volts
+smaller to much smaller than lead acid battery
+lights still work when engine is not running (safer if bike dies, handy when parked in the dark)
+probably makes starts and idling better/smoother than caps


Any users of very large capacitors on here to comment on the downfalls of them (reliability, light bulbs blowing, etc)? Also, just how small can I go on the battery and still have enough voltage spike cushion, as well as electrical capacity to easily start up my 4 cylinder Dyna-S ignition powered bike??



 

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Discussion Starter #2
As far as power for the size and weight, the Antigravity Batteries' smallest 1lb and 4.25" x 1.25" x 3.75" 6amp/hour offering is the best, but $108 best deal, $119 retail. Seems better for sure. Shorai didn't stack up for my needs. Caps or Ballistic are closer to my over-extended (total engine rebuild!) budget...
Antigravity Batteries the lightest most powerful and compact Lithium Batteries
 

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I've been using the Ballistic 4 cell "scooter" battery on my Yamaha R5 for 3000 miles with no problems. I'm also using a "Rick's" solid state reg/rectifier and points. These parts are so small you can hide them about anywhere.

Jim B
 

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I am running a '78 KZ650 on 2 capacitors that are very similar to the ones you picture here (larger though ~40k uF). I have them stowed and covered with dip so I can't easily tell the exact specs.
I am running original points. I found this thread while looking for other folks experience with running a similar setup with the Dyna S.

Let me see if I can recall this next part correctly...
I have my capacitors wired such (I recall this to be serial) that they have higher capacity but less resistance. This allows for me to get more capacity ( ~ N*.75, or some such calc) but not take as many kicks (only 1) to fill them up.

The only lights I have are 1 tail light and 1 head light.
The tail lite is a small trailer style light. Peterson Round Trailer Tail Light with License Plate Light, 2 Stud Mounting, Left Hand Peterson Trailer Lights 432000
The headlight eats a ton of amps. I think its somewhere over 8 amps. Blazer International Baja C52CW - Off-Road Light | O'Reilly Auto Parts
Kickstarting with that headlight turned on would be a never ending workout.

So, works great for me without the Dyna S. I'm interested to see what happens with the Dyna S.
 

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I've been using the Balistics scooter batteries in my Brit bikes for about the past two years with no issues at all.
All you need is something to 'light' the coils.
 

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Get a battery. I ran a few different caps for a while, and in the end it can suck for reasons you already stated, as well as lights dimming while the engine is idling if your charging circuit isnt putting out enough amps for the entire system to be happy. Downsides far outweigh the benefits. As long as you have a good reg/rec you wont blow out bulbs if you insist on caps.

What battery you get, it up to you. $100 for a lithium battery isnt bad, they last for a long ass time. Just get a good balance charger, so it lasts.

Im not getting into the math, but your thinking that putting two 20k caps in parallel = 40k is completely and utterly incorrect.
 

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I don't know why magnetos have not become the gold standard for café racer ignition systems, of throwing every useful electrical thing away for immaculate open triangle glory.

You don't need a battery of any kind, and the alternator only needs to pump out fairly easy low amps for the headlight and tail. I think the EM pulse from one could fry an iPhone at three paces, so remaining off the grid is dealt with extreme measures.

"Here's a R.C. Kawasaki setup with a mallory duel point distributor. The R.C. angle drive will accept any magneto or
distributor that is for a type 1 VW engine. Setup with a MSD distributor would be a great way to go." KAWIRCANGLEDRIVEIGNITION.jpg

Caps work fine on some bikes like SR500s and some others. Guys need to bear in mind bigger and bigger ones store a hell of a lot of charge unless "grounded out" and the charge dissipated. The big ones in Microwaves store plenty of charge that can kill if mishandled.
 

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magnetos for a GS750 are rare as rocking horse poop. Mags for KZ and cb's are way more common and are still in the $500-$1000 range which is a lot of cash for anybody. That's probably the only reason they are not the gold standard, cafe kids are fucking cheap.

I didn't think you could use caps on a GS750. the charging system is hella weak on those bikes and I don't think one kick will generate enough to start the bike.
 

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Wise words of the month: " cafe kids are fucking cheap. "

I've always thought riding a Big Twin Harley chopper with dual magnetos would set off security systems, fry laptops and cripple WiFi, and cut Police communications when stopped for a highway street-hassle. Pleasant thoughts, but only fodder for a movie I guess.

A steam punk could make a toothed belt drive mag with car bits, that would work fine, and look like something from Capt. Nemo's Nautilus. Creativity! Bah, Humbug!
 

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Wise words of the month: " cafe kids are fucking cheap. "

I've always thought riding a Big Twin Harley chopper with dual magnetos would set off security systems, fry laptops and cripple WiFi, and cut Police communications when stopped for a highway street-hassle. Pleasant thoughts, but only fodder for a movie I guess.
Or make the rider sterile, again one can only hope. I have a morris mag on the ironhead but even I don't understand the need for dual mags on a twin cylinder....no that is just getting fancy.

A steam punk could make a toothed belt drive mag with car bits, that would work fine, and look like something from Capt. Nemo's Nautilus. Creativity! Bah, Humbug!
if you take apart an ARD mag for a cb750 that is how they are setup. In fact the only part that is really proprietary is the mounting casting for the mag, everything else can be sourced from the pulleys and the belt to the mag itself (hint: it's a tractor mag).

I personally dislike belts, they are a service item and need periodic replacement. I much prefer chain, gear drive, or direct drive because of the longer service intervals.
 

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Discussion Starter #12
I didn't think you could use caps on a GS750. the charging system is hella weak on those bikes and I don't think one kick will generate enough to start the bike.
The weak point of the GS charging system is the regulator-rectifier. swap that out for a modern unit such as a Shindengen SH-775 & you will be putting out good reliable voltage at idle arount 12.7-13.1 volts. I just remembered that the 1980 & newer stators & rotors have several more poles than the earlier ones (like 11 vs 7?), & this may be of importance here with the battery delete mod, as you will have very slightly more voltage output, but more importantly - more frequent dc voltage pulses... Aha!

I bet with an SH-775 or compufire r-r and the 80&newer gs stators&rotors, that you would have the strongest charging system needed, & have no problem runningvwith a large capacitor.

Currently I'm leaning towards one of the three batteries... 8-16oz is pretty darn light.
 

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The problem with GS series bikes is an issue ( I think ) with the reg wired to only be regulating on one of the alternator circuits, not any problems with the regulator itself.

Investigate on a GS forum. Go to a GS forum, because I'm a little sketchy of the exact details.
 

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The problem has to do with the r/r being a shunt type, some wonky wiring routing one leg of the stator through the headlight and some other weird stuff that cause regs to fail and stators to burn up. If he's running the series type Shindengen regulator from a Polaris (which is like the size of a dinner plate) and all three legs are wired directly to a known good stator, he should be ok barring any other issues.

Chuck, have you looked into Posplayr's Solid State Power Box? I don't know if it will resolve the battery issue, but improving the electrical system's distribution, especially to the coils, should help you out.
 

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Discussion Starter #16
The problem with GS series bikes is an issue ( I think ) with the reg wired to only be regulating on one of the alternator circuits, not any problems with the regulator itself.
Yes, that is correct, the original units were total CRAP design. At least the charging system is easily upgradable, unlike all my CB750 friends who constantly have problems with charging, rotors gone bad, etc... No easy fix to get a permanent magnet setup there as far as we know at least. I'm very glad the GS is just a matter of swapping in a modern r-r and cleaning connections/ditching that switched stator leg whose switch gets dirty and causes problems ('76-79 GS's).

The problem has to do with the r/r being a shunt type, some wonky wiring routing one leg of the stator through the headlight and some other weird stuff that cause regs to fail and stators to burn up. If he's running the series type Shindengen regulator from a Polaris (which is like the size of a dinner plate) and all three legs are wired directly to a known good stator, he should be ok barring any other issues.

Chuck, have you looked into Posplayr's Solid State Power Box? I don't know if it will resolve the battery issue, but improving the electrical system's distribution, especially to the coils, should help you out.
One leg of the 3 phase stator is ran through a set of contacts on the headlight switch, so that it only connects that leg of the stator to the r-r if the headlight is on, therefore with the light off, the r-r is seeing less voltage and the stator is not having to shunt 1/3 of the load, therefore running it cooler. Unfortunately the switch gets dirty with age and use and causes problems that burn up that stator leg. Also, only one leg is regulated by the oem r-r, or original regulator and rectifier that were two separate parts in the first year or two. The Compufire or the Shindengen SH-775 (from late model Polaris RZR's etc) are both series regulators, they do not shunt (or momentarily short to ground) the excess unused/unnecessary voltage, they just internally disconnect the stator legs at a very rapid cycling to regulate the voltage, which does not generate excessive current to ground and excess heat that the bulk of them (the shunt style) do.

This SH-775 Shindengen IS NOT the size of a dinner plate! It is no bigger than most, about 3"x3"x1" off the top of my head. It's AWESOME. I've never clicked on Posplayr's sig file link, but I have seen it mentioned.

The stators on the Suzuki's are fine, but the r-r's and dirty connections/switches are what cause the stators to fail. The older '76-'79 7-ish(?) pole stators will deliver larger pulses of AC power to the rectifier, but with larger voltage drop gaps to fill by the capacitor or battery. The 1980+ stators have smaller poles, but more of them, so you will get less power out of each pulse, but more of them, but more gaps in the voltage pulses, but the voltage drops (gaps for a few milliseconds) needing filled by the battery or cap are smaller... Seems to me that the '80+ stators/rotors would require less capacitance to start up, and the earlier stators/rotors need a larger cap to fill in the larger voids in the current drop between pulses - BUT the pulses will deliver more energy, therefore a larger cap is needed to store that energy as it will be needed.
 

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Discussion Starter #17
My big question at this point is - can I still run my Dyna-S if I have a large enough capacitor, and will it still work the same, or is the lack of a battery going to really make it hard to start? a GS forum member confirmed that points will start fine on a cap or even on a practically dead battery if you are kickstarting, but a Dyna or electronic ignition will not want to kickstart if the voltage in the battery is very low. I have found this out three times now in three years, twice just recently on this junk battery, once when I first got my bike.
 

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Discussion Starter #18


Alien Motion Lithium Battery - LiFePo4 Lightweight Power Sports Battery

These appear to be made by the same outsourced Chinese/Taiwanese manufacturer as Ballistic's batteries. The case is the same, but this Alien Motion 2.2aH battery is about 1/4" smaller each dimension, weighs 1oz less, & is $7 cheaper than the 2.3aH Ballistic 100-010. I still think the 50cc scooter battery would probably do it, but maybe this one is a better bet. Both are more compact than the Antigravity battery, which is clearly the best & most regarded as far as durability.
 

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My big question at this point is - can I still run my Dyna-S if I have a large enough capacitor, and will it still work the same, or is the lack of a battery going to really make it hard to start? a GS forum member confirmed that points will start fine on a cap or even on a practically dead battery if you are kickstarting, but a Dyna or electronic ignition will not want to kickstart if the voltage in the battery is very low. I have found this out three times now in three years, twice just recently on this junk battery, once when I first got my bike.
From personal experience on my cb750 with a dyna S, if you battery is near dead or dead no amount of kicking will start it. Then again with points if the battery is totally dead it won't start either, but if it was near dead I could get it to kick sometimes.
 
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