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Thread: R25/2 Ignition Failure

  1. #1
    Administrator 20774's Avatar
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    R25/2 Ignition Failure

    There I was enjoying myself last weekend, and the bike quit on me. The charge/neutral lights were intermittent, and mostly they were pretty dim. The bike might start, but then almost immediately it would shut down. I inspected all the connections to the battery and even looking at the coil and regulator area inside the front cover. I couldn't find anything amiss. I was about ready to whip out my cell phone to call a buddy for help, when up he rolls on his mid '70s CB750...his ears must have been burning!

    We discuss things for a bit. I try one more time and the bike just won't run. Off he goes to get his trailer and I get her home. I quizzed a few people and it was Vech that wondered about my battery. I bought a maintenance free battery from him about 3 years ago. This was my first non lead-acid battery...I've heard about the AGM-type batteries falling off a cliff and not working. But Vech said that the singles vibrate so much, they destroy the sensitive AGM batteries...he doesn't recommend them anymore for the singles. Now you tell me!!

    I get one shipped from Vech. I put the battery acid in...interesting there wasn't enough in the package to fully charge each cell. I went up to Alamo BMW and they had some from other battery jobs and topped me off. Thanks Alamo BMW!! The voltage was 6.26v after sitting an hour or so, and now the charger is on it for another 20-24 hours or so. Trickle charging at 0.333 ma. Once it goes back in the bike, I'll need to verify around 7.2v charging when the bike is revving to be sure I get good charging and also no overcharging leading to acid spills.

    Here's a picture of the failed Blitz battery and the new battery. I didn't like the garish white case, so I bought some textured semi-gloss black Rustoleum. I sanded the case a bit and taped across the area where the fill lines are, then removed it after painting.
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    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  2. #2
    Administrator 20774's Avatar
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    Charged the battery overnight. Put it in and she started right up. Got that solved! Now I need to confirm the proper charging voltage...I don't want to have an unregulated voltage so as to overcharge the battery. My cheapo HF meter showed around 7.15v but it wasn't steady...I think that's the fault of the meter not sampling well. I'll need to find a better meter.

    I tried something else. I disconnected the +wire to the battery and used the voltmeter to measure the circuit by putting one lead on the +post of the battery and the other lead on the wiring harness. I measured 1 to 2v, so apparently I have some stackup of corrosion in the wiring system. I'll probably need to go through and clean the connections...see if I can improve that.
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  3. #3
    Administrator 20774's Avatar
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    As I've been reading up on this, my measurements in the previous post is the wrong way to go about it. I was using a voltmeter in-series to measure volts. One measures volts across or parallel to a circuit. Ammeters are in-series devices and is a different function. So, I will need to rethink this and do some proper measurements. I don't think I have a problem...I measured 6.4v last night and also measured 6.4v in the morning, so I don't think there is a drain in the system.
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  4. #4
    rabid reader dbrick's Avatar
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    Kurt,

    The overnight consistent readings do suggest no power drains.

    Still, you don't know if there are dirty electrical connections in the system; high-resistance connections require more current, and stress the bike's electrical system unnecessarily. If the bike starts normally and runs well and the new battery stays charged, you could adopt the "If it's not broken don't fix it" philosophy and leave things alone. OTOH, if you suspect or worry that something's wrong, opening and cleaning all the electrical connections in the bike (and making sure the connections are mechanically tight) would be a good idea.
    David Brick
    Santa Cruz CA
    2007 R1200R

  5. #5
    Administrator 20774's Avatar
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    David -

    I think I will adopt the wait-and-see approach. I am thinking about trying to install some kind of voltage meter on the bike so I can see what the generator is putting out and if the regulator is regulating. Then I can periodically check the battery terminal voltage to see if things are being kept up.
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

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