1972 T500 zero spark... Stumped

[ccwbbd89]

To make this as simple as possible, it was a barn find bike.
At one point the light worked but no spark....
Now, no lights, at the key there are 4 wires misc colors.
The I believe orange wire is showing a ground not power.
Any advice?

[jeff kushner]

Try hooking up a battery charger or good, charged battery and using this wiring diagram on this page, start tracing the power.

http://www.oldjapanesebikes.com/mraxl_G ... index.html" onclick="window.open(this.href);return false;

jeff

PS, if you had power at one point, it sounds like a bad/fouled connector.

[pearljam724]

To make this as simple as possible, it was a barn find bike.
At one point the light worked but no spark....
Now, no lights, at the key there are 4 wires misc colors.
The I believe orange wire is showing a ground not power.
Any advice?

Don't know much about T500's but properly test the battery with a multimeter. You may have a bad starter relay. You can also test the coils with an ohmmeter to see if they're any good. Batteries being good, is critical to starting and running pertaining to old bikes. Just because a battery holds a charge, doesn't mean it's any good. Starter switch could also need some cleaning. If the 500 has an electric starter ? Perhaps it's corroded inside. Open it and take a look. There are several items on a bike that complete it's circuit in order for it to fire and run. That should get you started until someone else comes along that knows more about the 500's in particular. Old bikes, especially ones that have been sitting are subject to corrosion and oxidation of electrical connections. Look for grounds and inspect their conditions. Engine, battery grounds, etc. How long since it has been started last ? You may have had power at the light. Because the battery holds a charge. But, the battery may have a bad cell. As a result, the next time you turn the lights on or attempt to start it. The battery falls on it's face and loses what charge it was holding.

[Bloop2]

Don't know much about T500's but properly test the battery with a multimeter. You may have a bad starter relay. You can also test the coils with an ohmmeter to see if they're any good. Batteries being good, is critical to starting and running pertaining to old bikes. Just because a battery holds a charge, doesn't mean it's any good. Starter switch could also need some cleaning. If the 500 has an electric starter ? Perhaps it's corroded inside. Open it and take a look. There are several items on a bike that complete it's circuit in order for it to fire and run.

Just wondering why we're giving advice on electric start issues when the T500 does not have electric start.

[jabcb]

The wiring diagram in Jeff's link is for an early T500, which has the light on/off controlled by the ignition switch.

For a later model T500 see:
download/file.php?id=690
download/file.php?id=1012

The bike has a single fuse for everything.

The bike may have been parked because of multiple electrical problems.
So proceed methodically & don't assume there is just one problem.

Post pics & ask questions if you need more help.

[titan performance]

Obviously check the single fuse......I had a similar problem many years back, and it turned out to be the block connector on the ignition switch.

[ConnerVT]

Having just had my 40+ year fuse holder crap out on me (now replaced with a new automotive blade style fuse holder), a couple of quick checks that are easy to do.

With the battery removed for all of these --

With the key off, check from the orange wire (easiest access is right on the turn signal flasher, as the orange wire goes to an exposed terminal) and a clean ground on the bike frame. It should be an open circuit (super high resistance, or "OL" on most meters). The orange is the switched hot +12V and shouldn't be grounded. There will be a little current that can flow through any lights that are on (turn off headlight, and only the tail light and neutral indicator), but it shouldn't be a low resistance.

With the key in the run (middle) position, check from the battery's positive lead (still no battery installed) and the same orange wire as last test. This should be a closed (very low resistance) circuit path. If not, possible issues are the fuse, fuse holder, ignition switch.

[pearljam724]

Don't know much about T500's but properly test the battery with a multimeter. You may have a bad starter relay. You can also test the coils with an ohmmeter to see if they're any good. Batteries being good, is critical to starting and running pertaining to old bikes. Just because a battery holds a charge, doesn't mean it's any good. Starter switch could also need some cleaning. If the 500 has an electric starter ? Perhaps it's corroded inside. Open it and take a look. There are several items on a bike that complete it's circuit in order for it to fire and run.

Just wondering why we're giving advice on electric start issues when the T500 does not have electric start.

Just wondering why are reading comprehension is a little poor ?

[ccwbbd89]

Thank yaull for the input, I will be running the test tomarrow.
I replaced the rear brake light switch , new battery ( tested old
Battery, was still good) and the lights and horn work, blinkers are
Solid no blink. There's one problem no spark, I am anxious
To see the results of the test..... Any tips on setting points?

[ccwbbd89]

Ran test, replaced few things an spark. But no fire, also the clutch rod popped out when I pulled
The cover. How do I place it in there correctly?

[pearljam724]

Ran test, replaced few things an spark. But no fire, also the clutch rod popped out when I pulled
The cover. How do I place it in there correctly?

You screw it in until you feel resistance. At that point back off the resistance by about 1/4 of a turn. Then hold the rod from turning as you tighten the nut. All clutch rods are the same. But, adjusting the clutch itself varies a little from bike to bike. The reason they back out is because the clutch is incorrectly adjusted via the cable. Test the coils with an ohmmeter, inspect the interior of the boots, cut the leads about a 1/4 inch off the end that enters the boots to expose a better contact and educate yourself on it's particular point system. Gaps, timing, properly clean points, etc. Sounds like you started with a mess. Continue to be persistent. She'll fire up.

[jabcb]

For both points, check the voltage at the wire that connects to the points with the points open & closed.
Also check the voltage at the orange wire that connects to the coils.

[ccwbbd89]

So I watched as it fire one cylinder will fire a couple times then stop. Has anyone had this issue?

[tz375]

I'm trying to leave this thread to T500 experts, but the last post intrigued me. Are you saying that the spark dies after a few revolutions or that the motor dies and you don'[t know if it's spark related or fuel related?

[Fearthepack]

Bad condenser will cause random bazar spark at plug. I had spark consistently at one plug and random at the other replaced the condenser bingo both have good consistent spark.