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Discussion Starter · #1 ·
This is a follow-up thread from the Wet Primary discussion. I have been investigating my start-up issues... and in doing some research, I've found some interesting points of discussion. I had previously posed this on another forum, but thought you guys might appreciate the discussion as well.

First, a bit of Background -
Before I tore into and replaced my Inner primary cover, I had some questionable starting issues. It always seemed like it just didn't have enough 'Uumph' to get the motor rolling; it would stall winding up to the first compression stroke.

I thought I fixed it by cleaning the cable contact points and slathering everything with dielectric grease. This provided only a marginal improvement. So... I embarked on finding a solution. After all, this is the same starter motor used to twist some pretty hefty V8 and V6 engines...

So... it all started with ordering another battery ground cable... this one I'm going to mount directly to the starter. What a deal too! It was like 1/3rd the cost of a new one!

<http://www.ebay.com/...dRfHAY&vxp=mtr>
I digress ... (Quoting previous post)

This thing has more flexibility than an over-cooked noodle!! And the gold tips just take the cake! I had to drill out one end for the 5/16" starter bolt, and it could be 6" shorter.. but wow... does it... just... feel... WEIRD being so flexible for its size!

Now that I've had a chance to read some of the links you've provided CD, these two ideas caught my attention -

The first, from Daytona Twin-Tec proposes to add a circuit breaker between the battery and the coil, thereby reducing the voltage drop from the long lead going through the kill switch.

<http://www.daytona-t...structions.pdf>

The second link is from Altman Micro and attempts to address the same issue, only in this case it takes a bit differently. Altman has a pretty nice write-up about the issue here: <http://www.amm.haan....tion/fr_qa.htm>

<http://www.amm.haan....high-compr.pdf>

Long story short, this starter is a very heavy draw, pulling down the battery voltage to 6v or more (<<4v according to Altman). So... what does this mean? Some explanation is required.

You've probably heard that all generators are (essentially) motors and vise-verse. Well, there is some truth to that. Once a motor is spinning at speed, it produces a 'Back Electro-Motive Force" (back EMF) which is to say, a reverse current. This reverse current then offsets the feed current requirement, reducing the overall load on the battery necessary to run the motor. This back-EMF is not present at start-up... unless your motor employes a start capacitor... which stores energy until its drained getting the motor started. This reduces the size of the motor and quantity of the windings necessary, allowing for a higher HP output without the added weight (and expense.)

Well, in this case, Altman proposes that the starter motor (which is nearly identical r to those used in cars, sans the spraag in lieu of a bendix) would work just fine if the battery was bigger (think Car Battery here) or doubled (as in two motorcycle batteries.) Without the extra capacity in the battery... this non-capacitive 'shorty' starter of ours slams into a high compression stroke... and the result is the battery voltage plummets.

Why is this an issue? Well, according to Altman, the drop in voltage fools the electronic ignition, causing a premature shutdown, resulting in a subsequent collapse of the coil voltage... which... causes a premature spark at the plug... BEFORE the piston reaches Top Dead Center. Twin-Tec seems to imply that a very similar thing is happening, although they don't go into detail about the specific problem like Altman did.

THIS is what I think... is happening with my scoot... When I press the start switch, the solenoid fires, the jack shaft engages the ring gear, and the primary assembly beings to turn... until it comes up upon the first compression stroke, when every thing stops dead in its tracks.

Altman says that on their system, this can happen as early as 50 degrees before TDC. This can even cause the motor to run in reverse... slamming back into the jack shaft, causing all manner of woes to the spraag clutch, which will take the full brunt of the force. Fun stuff, eh?

Its at times like this that I wish I still had an old analog Volt Meter... my digital one is not quick enough to capture how low the battery voltage is going.

So... while I still have the oil can out, I am contemplating adding both of these proposed changes - a relay for the coil voltage, and a diode in series with the ignition module's power, and a capacitor from there to ground. Do you think these modifications seem reasonable or necessary?? Will the second ground cable be sufficient?? Perhaps I'll sleep on it... and await your thoughts.

(end quote)

Ok guys - up for discussion - what y'all think?
kind regards,

Michael
 

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This is a follow-up thread from the Wet Primary discussion. I have been investigating my start-up issues... and in doing some research, I've found some interesting points of discussion. I had previously posed this on another forum, but thought you guys might appreciate the discussion as well.

First, a bit of Background -
Before I tore into and replaced my Inner primary cover, I had some questionable starting issues. It always seemed like it just didn't have enough 'Uumph' to get the motor rolling; it would stall winding up to the first compression stroke.

I thought I fixed it by cleaning the cable contact points and slathering everything with dielectric grease. This provided only a marginal improvement. So... I embarked on finding a solution. After all, this is the same starter motor used to twist some pretty hefty V8 and V6 engines...

So... it all started with ordering another battery ground cable... this one I'm going to mount directly to the starter. What a deal too! It was like 1/3rd the cost of a new one!

<http://www.ebay.com/...dRfHAY&vxp=mtr>
I digress ... (Quoting previous post)

This thing has more flexibility than an over-cooked noodle!! And the gold tips just take the cake! I had to drill out one end for the 5/16" starter bolt, and it could be 6" shorter.. but wow... does it... just... feel... WEIRD being so flexible for its size!

Now that I've had a chance to read some of the links you've provided CD, these two ideas caught my attention -

The first, from Daytona Twin-Tec proposes to add a circuit breaker between the battery and the coil, thereby reducing the voltage drop from the long lead going through the kill switch.

<http://www.daytona-t...structions.pdf>

The second link is from Altman Micro and attempts to address the same issue, only in this case it takes a bit differently. Altman has a pretty nice write-up about the issue here: <http://www.amm.haan....tion/fr_qa.htm>

<http://www.amm.haan....high-compr.pdf>

Long story short, this starter is a very heavy draw, pulling down the battery voltage to 6v or more (<<4v according to Altman). So... what does this mean? Some explanation is required.

You've probably heard that all generators are (essentially) motors and vise-verse. Well, there is some truth to that. Once a motor is spinning at speed, it produces a 'Back Electro-Motive Force" (back EMF) which is to say, a reverse current. This reverse current then offsets the feed current requirement, reducing the overall load on the battery necessary to run the motor. This back-EMF is not present at start-up... unless your motor employes a start capacitor... which stores energy until its drained getting the motor started. This reduces the size of the motor and quantity of the windings necessary, allowing for a higher HP output without the added weight (and expense.)

Well, in this case, Altman proposes that the starter motor (which is nearly identical r to those used in cars, sans the spraag in lieu of a bendix) would work just fine if the battery was bigger (think Car Battery here) or doubled (as in two motorcycle batteries.) Without the extra capacity in the battery... this non-capacitive 'shorty' starter of ours slams into a high compression stroke... and the result is the battery voltage plummets.

Why is this an issue? Well, according to Altman, the drop in voltage fools the electronic ignition, causing a premature shutdown, resulting in a subsequent collapse of the coil voltage... which... causes a premature spark at the plug... BEFORE the piston reaches Top Dead Center. Twin-Tec seems to imply that a very similar thing is happening, although they don't go into detail about the specific problem like Altman did.

THIS is what I think... is happening with my scoot... When I press the start switch, the solenoid fires, the jack shaft engages the ring gear, and the primary assembly beings to turn... until it comes up upon the first compression stroke, when every thing stops dead in its tracks.

Altman says that on their system, this can happen as early as 50 degrees before TDC. This can even cause the motor to run in reverse... slamming back into the jack shaft, causing all manner of woes to the spraag clutch, which will take the full brunt of the force. Fun stuff, eh?

Its at times like this that I wish I still had an old analog Volt Meter... my digital one is not quick enough to capture how low the battery voltage is going.

So... while I still have the oil can out, I am contemplating adding both of these proposed changes - a relay for the coil voltage, and a diode in series with the ignition module's power, and a capacitor from there to ground. Do you think these modifications seem reasonable or necessary?? Will the second ground cable be sufficient?? Perhaps I'll sleep on it... and await your thoughts.

(end quote)

Ok guys - up for discussion - what y'all think?
kind regards,

Michael
It makes sense to me, but only to the extent of my very limited knowledge of things electronic. The huge startup draw on the battery, I get. And even the compression stroke firing that kicks the pinion gear out of engagement, I kind of get. And if installing the relay and capacitor solve it, that's great! I don't feel confident enough with this stuff to try it on mine, but sure would like to hear how it goes with yours. Is the starter relay that Indian Moto Parts sells the one you will try?
On mine, I am planning on relying on the new cables, good battery, and will probably add that second ground cable also. As a backup, there is always the push button that I put on the solenoid, which could be useful for cold starts. Mine generally started really well when it wasn't the first start of the day.
 

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Discussion Starter · #5 ·
Yes... I believe Mark's relay is a 40/30a relay that takes the place of the stock original. Because of the high current draw... caused by the magnetic bounce-back (read: spark) from the solenoid coil's magnetic field collapse when it breaks open... causes undue wear (read: pitting) on the points in the circuit relay, and thus premature failure.

That said.. a heavier relay, such as a 40/30a (read: 40 amp normally closed; 30a switched open) is built to handle the heavier current draw. Still, a good solution is to add a diode across the coil of the relay to 'snuf' out the spark caused by the relay coil's magnetic field collapse.

Think of the ignition coil generating a spark for a spark plug. This happens when the power in the coil is broken by the points. The magnetic field collapse induces a spark... more so in the high tension side... but also in the points side of the coil. The points would normally be eaten alive by the arcing in fairly short order, were it not for the capacitor attached to them, to soak up that excess current. That's why points and "condensor" (the capacitor) are replaced together.

The electronic ignitions in our bikes did away with the condensor.. and the points were replaced by solid solid-state transistors. (A transistor is like two diodes placed back to back.) So adding a diode across the coil in a relay will help extend the life of the points contained with.

I do not know if Mark's include this diode or not. But simply going up in amperage will extend the life of the relay considerably.

There are many good reasons to add relays to the circuits on our bike. One for the head lights... removes the high current draw through the headlight dimmer switch. This will drop the current load from several amps to 1/4 amp to flip the relay. Same for the power sent to the coil - again, like the starter solenoid, a diode should be added here as well, to prevent damage from the reverse spark... AND to protect the other electronics in the system. Some folk even add a relay to their horn circuit.

One modification I am now considering is to add a 30amp breaker to the alternator circuit... so it doesn't short the rest of the system when it craps out. Also thinking of adding a Type 1 30amp relay to the headlight circuits, so that should the headlight or spots short out, they don't burn up the wiring harness.

At any rate... there is a lot here to consider... so I think what I'm going to do.. is study the problem in depth.. draw up some schematics... and put it out for discussion.

Keep in mind that Altman's electronic ignition was an early design, and perhaps didn't take into consideration this back EMF from the coil... or such a low battery voltage drop. In all honesty, I think this large 4700uf capacitor and 200v 3amp diode was a bit much for an add-on... and should have been incorporated into his ignition module.

Anyway.. more about all this when I have given it some quality engineering time.

kind regards,
Michael
 
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