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Could Use Some Electrical Help...

1718 Views 18 Replies 6 Participants Last post by  retro
So for as long as I've owned my Honda 300 it's given me problems starting. All my mods are in my sig, so you can see what I have...

IF it's left outside overnite and temps are around freezing or very chilly the quad will barely turn over. I need to kick it. Fires up 1st kick.

IF it's left for days or weeks without starting in a heated garage, it's a crap shoot if it will fire up or if I need to kick it.. bur way better than if it was left out overnite. Always first kick it's running.

IF I have to kick it because the battery won't fire it up, & I run the quad for a little bit or hours, it will always fire right up with the battery.

I had installed a new battery over a year ago thinking it was the culprit, however it continued to do the same thing.

I do have the winch wired up to the aux pink wires direct. it's not with key power.

I'm leaning towards the rectifier?? I remember a while back I tried to check the voltage while cranking & was getting something like 7v, but while running it was 13v or 14v if memory serves me correct...

I would love some advice so I can check some things before I just start throwing $$ at it replacing parts!!!!!

Thanks in advance!
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Does the starter crank it over good while the decomp lever is pulled up? Next thing I'd look at are the battery and ground cables. They might need to be replaced with fatter cable... to carry higher currents. The solenoid should be OEM too. I assume the battery is a stock AGM, 12 ah size?
Well there ya go... got a BBK and a cam that might be producing very high cranking RPM cylinder pressures. You might try making a set of 4 gauge battery/ground cables from welding cable and solder on some heavy copper ring terminals... but you'll still probably have to use the decomp lever to start it. I wonder what your dynamic compression ratio ends up at with that cam...? Its gotta be running real close to detonation I'm guessing... since cylinder pressure is excessive while cranking.
Another thing that might help a lot is a freshly lubed starter motor. I'd take it off and disassemble it, clean it up in some mild soapy water and rinse and dry it well over some moderate heat. An alcohol rinse will help speed drying too. Then lube each bearing/bushing end of the armature with synthetic grease. Replace brushes if they are wearing short while you're in there... but don't remove the dark layer of graphite from the commutator, because its a necessary dry lubricant layer that prevents the copper from arcing and eroding.
Here is a dynamic compression ratio calculator:
Wallace Racing: Dynamic Compression Ratio Calculator

Rod length on the TRX300 is 123 mm (4.842505 inches).
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No, more than likely the battery has lost a cell... You can find out by taking it off the bike and recharging it using a small battery charger. Let it sit for 24 hours after charging and then measure the voltage across the terminals. Any measurement less than 12.6 volts is a weak and failing battery. 12.4 volts or less is already junk. The charging system will never reach its rated voltage level (~14.5 volts) output connected to a 5-cell battery... follow me?
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Those figures aren't bad considering every meter measures differently. They are consistent too... I still think the battery took a dump on ya. I'd try to charge it then wait 24 hours for the battery to return to its resting voltage, then measure it. My guess is it will measure below 12.2 volts at resting voltage which would indicate that it lost a cell.
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