Hey all. I bought these Bike Master turn signals, hoping to replace my OEMs on the rear: http://www.motorcycle-superstore.com/44761/i/bikemaster-spear-led-turn-signals. The site said they're compatible but I'm finding that's not quite the case. Has anyone installed these as rear signals?

I'm still learning my way around the bike and trying to learn how to make these kinds of mods. I have a decent set of tools but not any kind of sophisticated garage or anything.

Anyway - any help is appreciated! Thanks.

OK, areas of concern...

Number 1, you're replacing filament bulbs with LEDS, so your blinker relay won't work. You'll need to add a Blinker Buddy or some type of resistor so the draw is the same.

Number 2, just about any type of turn signal can be replaced, the mounts don't need to be the same, the locations don't need to be the same, you just need to securely attach them to the bike and hook the wires up correctly.

Number 3, back to the electrical load, if you switch to LEDS and reduce the electrical load by 15 or 20 watts, you need to add a comparable load to prevent the rectifier from having to absorb the extra wattage. The electrical systems on our bikes are not designed to cope with much of a swing, and 20 watts may not sound like much, but that's 10% of the alternator output... so it's a pretty good chunk of the system load.

koehlerrk wrote on 06/14/15 at 16:49:06:



I can't see how the wattage of the turns signals makes much of any difference.  You use the turn signals maybe 1% of the time you are riding the bike......maybe?  I have had LED turns signals and tail light on my bike for the last 3 years and I have not burned out anything yet.

I do believe however that you are going to find out those cheap (NON-DOT) turns signals are completely ineffective in the sunshine or even daylight.  Sure you can see they are blinking if you stare at them - but they won't get the attention of a distracted driver.  I tried a set of them on my bike and when tested in the sunshine....they were worthless and I sent returned them. You really need better turn signals.  Look for some original equipment "take-offs" from the sport bike owners who remove really nice turns signals to put on crappy LED's that can't be seen....they are nice bright lights that will allow drivers behind you to see them.

Thanks for these detailed replies, all! And the info on what to watch out for. Boogie_with_stu, I really appreciate those links to the stock lights on eBay. I looked about a week ago and, for some reason, couldn't find them at a decent price. But this is just what the doctor ordered. I chose to return the LEDs and buy the OEM parts off eBay. Keep things simple for now.

A Savage get together would be great! I'm down in Austin and I've seen at least two Savages out on the road a few times so they're out there somewhere...

Glad I could help

My left rear signal was damaged when I got this bike...the rubber mount was torn in the middle. I looked for ages to find the shock mount just by itself, and in the process I found those OEM signals.

As for LED signals, I dont think it is anything that will hurt the bike...it's just the fact that the blinker module gets wonky and runs too fast. Constant draw running lights or headlight, that is different. I dont know much about how the bike electrical system is loaded (ie, balanced, unbalanced, open end, regulated) but it doesnt seem right to me that the rectifier HAS to put out the standard 200 watts or so. Pulling more would certainly overload the system, but pulling less should just mean that there is power to spare.

Just like a regulated DC power supply, it should put out about 12 Volts DC regardless of the load on it until the load is too much...at which point the voltage would sag below the optimum 12VDC.

We have a permanent magnet alternator on our bikes.  It runs at full output all the time.  The rectifier/regulator does NOT work like the regulator on a car alternator.

The RPM of the engine is the only governor for what comes out from the stator.

The reg/rec has the job of changing the AC from the stator to DC which we can use. That is the rectifier part.  The regulator senses the output voltage of the R/R on the DC side.  When the voltage goes above the set point, the regulator grounds out the extra power.  

Our voltage is regulated by varying the load since the output of the alt can't be varied.  Any power over and above what is required by the bike is shunted to ground inside the R/R.  That's why the fins.  It gets hot doing this.  If you free up extra power and don't do something to absorb it again, it's just more power the regulator has to short to ground.  This increases the load on the regulator and the amount of heat it generates.

If the system were perfectly balanced, you wouldn't need the regulator part, just the rectifier.  But since output varies with RPM, allowances have to be made so that charging occurs at normal speeds. At speeds higher than the manufacturer considered their 'normal', excess power is generated, if there is nothing to use the power, it is shorted to ground, heating up the regulator. At lower than 'normal' speeds, the system puts out power but not enough to cover all of the loads...you are partially running off the battery. The regulator is allowing every bit of power generated to go straight through to feed the bike. The  regulator will stay nice and cool when operating like this.

Too much excess power is actually bad for the R/R.  You want it to dump some power but not lots of it.  This is why our charging system only has 1 or 2 amps left over for charging the battery. So, it won't cook the battery and it won't cook the regulator when the battery is full.

I hope this helps someone a little with understanding our charging system.