Starter Switch/Relay Issue - 1979 550

[kulchur]

After very slowly rehabbing my bike over the summer, I finally have everything together and have run into a new-to-me starter/electrical issue. Hoping someone can help!

For context: I sheared off an oil pan bolt while changing the oil and left the engine open for a few months while working on other projects. I took the engine to a machine shop to get the threads cleaned out, reinstalled the engine, closed everything up and got some oil into it. It hadn't been turned over at all in maybe a year by the time I got everything back together. I don't believe it's seized and it's turning over well now that everything's back together.

The problem: After getting everything back together, I went to hit the starter switch and got nothing — no click, no turning, no drain on the battery. Dead silence. I charged the battery overnight, which improved the strength of the lights, etc., but still no click. I replaced the starter relay yesterday, but that didn't immediately fix it.

The (brief) solution: I decided to start kicking over the engine until I built some compression and got it started. At some point during the kicking process — maybe halfway to getting the engine running — I tried the electric start again and got sustained clicking and turning for about six seconds. I didn't want to push it, so I stopped using the electric start. I kept kicking it over until I did get it to fully start and idle for a few minutes with no sign of weakening or dying. (The only issue was a bit of black exhaust when revving, which I'm chalking up to an engine that's just getting used to running again, fingers crossed.)

I was hoping that having a fully running engine would solve whatever was blocking the electric start, but no dice. I killed the bike and tried the starter button again, but it had gone silent again. By the end of the night, the electric start had worked, but only for a few seconds.

Any advice? A few things I've seen that could be possible solutions:

- I see on the starting system diagram that there's a fuse between the battery and the ignition switch and starter button. I haven't replaced this fuse yet. Would this fuse dying or being poorly seated explain an intermittently dead starter button?
- The battery's getting old — it's probably a few years old at this point and is growing some funk on top. Would a new battery help?

Beyond that, I'm stumped. When I put everything back together, I made sure all the electrical connections were routed correctly, matched and seated well. Your expertise is appreciated!

 

[Guest]

That is classic symptoms of a low battery with the solenoid chattering. It also pulls a lot more current and has been known to weld the solenoid in the on position on some bikes. Check the fluid level in the battery, if low top it off with distilled water and charge with an appropriate Trickle charger. If the battery fluid level is low that might also indicate an overcharging condition boiling fluid out of the battery. It sounds like the battery might need replacement, but check out the charging system because if it is overcharging you will eventually toast a new battery.

 

[geol]

As far as the battery goes, the battery on a bike is small and has only a few plates. If the bike sits for an extended length of time without being on a float charger, the plates tend to sulfate and won't hold a charge as they should. You can easily check for this condition by buying a small hydrometer at an autoparts store. This thing looks like a small eyedropper with colored balls on the inside. You put a piece of supplied hose on the end into the cell and suck up some fluid. If all the balls float, the cell is OK. The legend on the hydrometer will say something like: X number of balls don't float, the cell is marginal BUT if you have any balls not floating the cell is dead/or near dead and the battery is toast. If you find the battery is OK (check after topping with distilled water and charging as OldVet66 advised) then it is just a matter of using a low amp trickle charger to bring the battery back up to snuff after charging for about 8 hours or so.

Clicking means there is enough power to close the electrical loop in the solenoid but not enough power to turn the starter over or the starter will turn over a little without enough power to get it moving fast enough to start the bike. As has been noted, buy a battery tender AND a trickle charger which is a 12V charger that charges at 1A or so. These are pretty much must have if you intend on living in the vintage world.

 

[bwringer]

Check the battery with a voltmeter. Sounds like it's likely toast.

One other commonly overlooked issue is that the plate the solenoid is mounted to must have a good ground path. The plate is rubber mounted, so there must be a clean connection back to the frame or the solenoid will only work intermittently and weakly.

 

[kulchur]

Sounds good. Thanks, all. I've checked the electrolyte levels and it seems within reason ? but it's three or four years old at this point and it's just likely dead. I left it off the tender through this past Minnesota winter and I'm sure it's breathed its last. Off to the battery shop.

 

[geol]

If you can afford the bite, an AGM battery will last longer if it goes through periods of disuse. It is a sealed glass matt battery. Make sure the posts on the battery you buy are oriented the same way your current battery posts are oriented. The next thing is to make sure that the battery width/length are the same and that the battery is not too high where the seat pan might touch the anodes. Try to get the highest number battery that will fit. My current battery is a 15... I would guess that the OEM battery is a 14. A 15 has more cranking power. It is also a bit taller than the original battery I think.

 

[Guest]

I left it off the tender through this past Minnesota winter and I'm sure it's breathed its last. Off to the battery shop.

That will definitely do it if the charge is low and it freezes. Do check your charging system. My '78 and '79(parts bike) both had overcharging problems that toasted the stators. The '79 only had 4,600 original miles on it so I'm pretty sure the old split rectifier regulator systems were a lot worse than the later combined units and they weren't winners either. A series R/R transplant would be a wise upgrade.

 

[kulchur]

Update: New charged battery is on the bike and I fiddled around with the fuses (none blown) to make sure they were seated properly. Not sure which did the trick, but it's got a happy electric start and is purring nicely. It only took me until AUGUST 31 to get it running this year

I'm hoping to sell it to finance a larger bike, in the 850-1100 range. I'm a tall, bigger guy and the 550 is great for in town, but a little spooky on the highway.