charging problems

Go to www.electrosport.com and use their troubleshooting page on the website. It will help a lot.

ok, so i just got my new rectifier from ricks motorsports and plugged it onto the bike. problem solved, i thought. so heres what happens. the good news is the bike doesnt try to die on me when i come to a stop while holding the clutch in. the bad news is after i turn the bike off after its hot, it has a hell of a time even trying to start. is this common? is the starter being affected by the heat radiating off the engine? after i let the bike cool the starter spun up normally, but when the bike is hot the starter barely turns over which made me believe it was the rectifier not charging the battery. what can i do? what can be done? it sucks that i have to wait for the bike to cool off before jumping back on it to ride away. imagine going to a gas station and trying to take off after fueling up. how embarrassing.

Hard starting after being driven for a while might indicate it's time to check the valve clearances.

To confirm this, do a compression test after getting the engine hot. On these engines, the valves wear toward the cams possibly loosing compression. Metal expands when hot, in your case do a simple compression test.

Another thought is to remove the starter motor and check the bushings and brushes for wear. The local electric motor rebuilding shop should be able to test the commutator for shorts/open windings.

new developments! but still bad news though. my dad was doing some tests on the electrical system again to see what he could find. he's come up with a few ideas. one is the new 810 wiseco piston kit bumps the compression too high up for the starter to handle when the engine is at standard operating temps. he says he also was inspecting the magneto and feels that it isn't very strong, which could be why the battery isn't able to charge all the way up, even while revving. so my new questions are this, where can i get a high torque starter thatll fit this bike (if i need one) and where can i get a stronger magneto? and does any of this sound out of whack? another thing to add. before even starting the bike he was checking out the fluid level of the cells on the battery and removed the cap on the sixth cell and it immediately sprayed fluid out of it. he says he's never seen this in the 20+ years of him working on engines. the battery was bought at walmart, which im worried might be the cause, i figure ill pick up a sealed gel battery and see if that doesnt fix anything.

I'd ask Wal-Mart for either an exchange or refund. Does the battery have a warrenty?

Possibly the existing battery cable need to be up graded to a larger size. What came with the bike is around 8 gauge, I think you need 6 gauge to handle the higher current.

Local battery shops and welding supply stores can make new cables for you, bring your old cables along or take careful measurments as the cables are usually sold by the foot.

Welding cable is much more flexible and can fit in tighter places than what you've got now.

Imo the existing starter and alternator are likely okay as is.

After replacing battery, may quick check charging system by measuring voltage across battery terminals at idle (look for 12~13+ volts) and at 4000 rpm (look for 14~15 volts).

Would also assure integrity of ground connection where negative battery cable attaches to rear of engine.

Good Fortune!

Yes, the Dyna S will use roughly double the power of the original ignition, or even more, but that's still not enough to explain the dead charging system results.

Even with no charging system at all, battery voltage will creep up slightly with RPM. This is because simple ignitions (like the KZ and Dyna S) actually use less power at higher RPMs. If the voltage only goes up a few tenths, but is near 12v, then the charging system is basically non-functioning.

It sounds to me like the reg/rec is dead.

Your bike doesn't have a magneto. It has a permanent magnet alternator (which looks a little like a magneto, I guess). The magnet part is the rotor. That's actually the flywheel on the motor. The part with the wires is called the stator.

If the magnets are weak, you can get another on ebay probably. If the stator is bad, you can get new, heavy duty ones from online sources. Try Z1 or Dennis Kirk.

i just put a new regulator on. so thats ruled out.

Is the reg/rec grounded? There is a ground wire that must be connected for it to work.

Hundreds (at least) of 750/810 bikes running around with the stock starter and no problems.

i took the bike out for a spin today after buying a new sealed battery, hoping that would fix the problem, but its apparent to me now that something electrical is wrong with my bike. i really hate this bike now. its terrible but true. ive dumped so much money into it though that i could never recoup my losses though. i thought id mention that at around 4k rpm it is around 12 on the voltmeter. thats not right, right?

Sorry to here about the Hated Bike.
Have you and your dad tried to unplug the head light to see if the volts come up at 4000r's? This will get rid of some of the extra load you added with the Dyna. All of the advice given for the connections, has that been followed?
With the yellow wires disconnected at the Stator/ regulator connection, what was the AC voltage readings of the Stator at Idle and 4000 as per FSM testing? The AC voltage test will show if the stator out put is enough. Then it up to the connections to the R/R to make/ handle the DC voltage.
Did you get the battery tested/ replaced?
Another easy test for the 2 main circuits at the R/R plug, Red/ White + and Black/ Yellow -, is to use a head light bulb at these 2 wires to pull some amps through the connections, maybe even 2 in series. This will test your ground and back to battery + connections. I believe you will also have a Brown wire, this is feed from the Ignition switch, but is really the voltage sensing wire for the reg. I know that if this voltage is low it will cause an overcharging condition, and probably boil the battery free of electrolyte. If for some reason it is not receiving power I believe the reg will not function.
As Patton says, GL