1974 Honda XL70 lights

[gumpit]

All my lights work. But stop lighting and blinking if I rev it up. When the rpms come back down they light and blink again. Thoughts

 

[the beekeeper]

Does it have a battery installed?...............If so, is it any good?................Tom.

 

[chrisr]

Did you change the flasher? What is the voltage idling and when the rpms are up?

 

[Tom S.]

That bike probably does not have a voltage regulator and must have a good working battery to keep bulbs from blowing when you rev it up. That can get expensive if it has an unobtanium sealed beam headlamp. Just speaking from experience here... :doah:

 

[gumpit]

New battery, new flasher. I'll get voltages today.

 

[Mariah]

Gumpit...You have the polarity reversed from the charging coil. When you rev the engine it drives the battery voltage down to near nothing. Reverse the wires from the charging coil so +&- are working together instead of bucking against each other...problem solved. Also, if the battery was connected backwards it would do the same thing.

 

[chrisr]

If the battery was hooked up backwards, the main fusible link and/or fuse will pop/burn up. At idle the bike should be something higher then battery voltage > 6.3 for 6 volts and 12.6 for 12 volts and reved up about ~ .5-.7 higher for 6 volts and/or ~ 1-1.5 volt higher on 12 volts. I would check your voltage regulator for a good ground clean connection on the connector and ground on the regulator and if still bad after cleaning, replace the regulator.

https://www.ebay.com/sch/i.html?_fr...S0&_nkw=honda+xl70+voltage+regulator&_sacat=0

Gumpit...You have the polarity reversed from the charging coil. When you rev the engine it drives the battery voltage down to near nothing. Reverse the wires from the charging coil so +&- are working together instead of bucking against each other...problem solved. Also, if the battery was connected backwards it would do the same thing.

 

[creia]

That bike probably does not have a voltage regulator and must have a good working battery to keep bulbs from blowing when you rev it up. That can get expensive if it has an unobtanium sealed beam headlamp. Just speaking from experience here... :doah:

Tom is correct. Just like our 1969 CT90 the battery on this bike acts as the voltage regulator. That is to say there is no separate and dedicated voltage "regulator". You MAY have a bad RECTIFIER which converts the AC voltage from the charging stator/coil to DC voltage used by the lights and for charging the battery. If you bike has the old/original OEM selenium rectifier it is long past its expected/useful lifespan, and it MAY be going bad which COULD be source of your problem. They sell replacement rectifiers that have much improved technology. Long time OldMiniBikes member "Inventorpardue" ("Jon"- heck of a nice guy too!) is THE GURU on all things electrical on bikes. He checks in from time to time so hopefully he will see your post or you could PM him
Michael

 

[gumpit]

Just over 6v at idle up to 7v when you are at full rev. The Headlight works fine. Its just the directionals that seem to be the issue.

 

[chrisr]

Did you get a 6v or 12v flasher. They are not the same.

This may be a helpful link...

https://thumpertalk.com/forums/topic/727703-turn-signal-problem/

New battery, new flasher. I'll get voltages today.

 

[gumpit]

Says 6.4v on it

 

[chrisr]

Have tried hooking a 6v battery charger with the bike not running and seeing the voltage and results in regards to the turn signals? Also, are all the turn signal bulbs 6v or a mix of 12v and 6v. They should all be 6v.

If a diode in the rectifier is failing can cause a AC ripple affect which can kill batteries as well as not able to put out the same output at peak. Grounding and bad connection issues on these old motorcycles is pretty common.