Hello all, I was wondering if anyone could suggest a proper way to test a Starter Relay for my 1972 R75/5? I have read a bunch of the informative tech articles here and looked around for a good way to do this- as I have tested the battery, and starter switch (both perfect) but still getting the telltale tick-tick-ticking sound when starting. I do NOT have a drop off of power to lights, etc. when starting, and I can kick start with success, so I suspect the relay and want to test it before buying a new one.
A corollary is to this is I'm wondering if anyone has a suggestion regarding an upgrade or way to workaround the cold starter lockout issue, which my bike definitely suffers from. I read the fantastic article from Snowbum regarding a DIY fix to the relay to account for this, but it feels a bit out of my league (I'm not very adept at soldering) and it seems like something I would try on my current relay AFTER I have replaced it with a new and/or upgraded one. Cheers, Eric
• The Starter Relay simply routes low current 12VDC to the starter motor. You can unplug the small wire at the starter motor, affix a 12V mechanic's test lamp and when you push the starter button, the light should light up. If it does, then the Starter Relay (and all the wiring between the button and the Starter Motor) is good.
• The more likely place for failure is inside the starter. Inside is yet another relay (they might call it a motor contactor or solenoid, but it's still a relay). The difference is that this relay carries very high current and is much more likely to sustain damage due to arcing and burning.
You can test that easily enough by jumpering from the large battery cable connection on the starter to the smaller terminal you just disconnected for the first test. A piece of wire 2" long is all it takes. The starter motor should start spinning the engine when that connection is made. If it doesn't, then the starter needs rebuilding.
Hope this helps.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
@wobbly Thanks for the info! I did all the testing to cover the bases (Relay, Starter switch, starter motor, & battery) In the end, I got a super economical Starter relay from Rick at Motoelekt and a new Scorpion Battery from BatteryParts.com and the old gal starts like a dream! Now on the hunt for tail pipes...
@16810 Now to the more serious issue...
Starter motors are extremely expensive, and very useful to have operational. A known failure point is that the grease in the starter motor bearings oxidizes over time and begins to coagulate. That is to say, the viscosity gets so thick that the motor has trouble turning over. When this happens, the motor will pull more current from the battery and burn itself out.
This simple fact is probably the Number 1 contributor to burned out Airhead starter motors. Dang Airheads simply stay on the road too long for their own good !!! ?
Make a plan to remove the starter motor and simply re-pack the grease in the motor bearings. Use American synthetic wheel bearing grease with moly. Synthetic grease simply doesn't oxidize as fast as mineral oil based grease. Your starter will be good for another 50 years.
AND... you'll hear your starter spin faster and your bike will start faster and easier.
Then look up the price of a replacement starter motor and mail me half your savings !! ?
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
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