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Post by mike932 on Feb 5, 2015 19:47:43 GMT -6
Hi everyone. Newbie here. Thank you in advance for your help. Three months ago, I bought a 1988 Yamaha Riva 125cc on Craigslist. It has worked flawlessly until today. Went for a 40-mile hilly ride. While riding up a hill, the engine sputtered a few times. I pulled over to be safe. 10 seconds later, the engine stalled. Tried restarting it 5 times before it restarted. Then it stalled again. Waited 30 minutes in case the engine overheated. It started, I rode a few hundred yards, and it stalled again. Would not restart. Started an hour later, but stalled when I turned off the high beams. The front lights no longer work either. They will come on once once in a while and then turn off again for no reason. Battery reads 12.5 volts using multimeter. Fuse looks intact. I am guessing a power wire to the front of the scooter is faulty? Please advise. Here is the Riva manual.... www.motorscooterguide.net/Manuals/Yamaha_XC125_Service_Manual.pdf |
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Post by jerryscript on Feb 5, 2015 21:19:00 GMT -6
You are probably right about a loose connection. A simple one to check first is the spark plug boot and wire. I spent a month last year thinking I had a fuel/air issue due to bogging and dying and having trouble electric starting. Turned out my spark plug boot was bad (one of those rip-off performance coil/boots), I put the stock one back on and haven't had the issue since.
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Post by jct842 on Feb 5, 2015 21:32:02 GMT -6
Get your meter out. There probably is no spark and go from there. It would not hurt to get all the plastic off and physically see that all the connections are firm and no chaffed or broken wires. There should be a wiring diagram in the library here. On older machines it is not uncommon to find a wire broken with insulation intact and also broken at a connector and yet it looks good from the outside.
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Post by cyborg on Feb 5, 2015 21:36:18 GMT -6
Yes it does sound like an electrical issue,,,something came loose or a wire chafed ,,,connector bad. Something silly without being funny at all,,, or the coil went bad,,,,see if it will start if it's dead cold then sputters and dies when warm,,,,if it starts cold ok then dies when warm it very well may be the coil
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Post by mike932 on Feb 5, 2015 21:54:50 GMT -6
Just tried to start it again. Turns out NONE of the front or rear lights work. Horn does not work. Starter does not turn over. Battery and fuse seems fine. This could be good news, right? Because it sounds like the connection problem should be near the battery instead of near one of the lights. In other words, the problem should be easier to find? I will remove panels tomorrow and play with the wires.
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Post by cyborg on Feb 5, 2015 22:09:07 GMT -6
This actually is great news!,,, bet $20 it's a connector came loose on your ride
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Post by mike932 on Feb 5, 2015 22:10:58 GMT -6
I hope so! Why would a running engine die if electrical power dies? Is it because current is no longer going to the spark plug?
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Post by cyborg on Feb 5, 2015 22:16:11 GMT -6
Correct,,,the ignition system shut down,,,,so check all the terminations around the coil and cdi first then you can go further into the system if the need arises
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Post by JoeyBee on Feb 5, 2015 22:16:24 GMT -6
This is a very good video walking through checking all electrical components.
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Post by mike932 on Feb 5, 2015 22:21:52 GMT -6
LOL! I actually started watching that same exact video 10 minutes before you mentioned it.
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Post by JoeyBee on Feb 5, 2015 23:10:31 GMT -6
LOL! I actually started watching that same exact video 10 minutes before you mentioned it. That is funny. It is a very good video. The author is testing all electrical systems to diagnose a faulty CDI, but the explanations for each system is very good. Once you do find the problem part we have several electrical gurus here. |
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Post by jerryscript on Feb 5, 2015 23:44:27 GMT -6
I would be suspicious of the wires coming from the stator (perhaps the stator itself).
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Post by mike932 on Feb 6, 2015 9:47:39 GMT -6
Turned key this morning. Lights came on. Scooter started. Turned it off. Would not start again. Lights will not come on again. Opened panels. With key turned, I wiggled all electrical wires but lights did not come on.
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Post by JoeyBee on Feb 6, 2015 9:55:17 GMT -6
Turned key this morning. Lights came on. Scooter started. Turned it off. Would not start again. Lights will not come on again. Opened panels. With key turned, I wiggled all electrical wires but lights did not come on. Do you know if your system is A/C or D/C? And have you tried charging the battery? |
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Post by mike932 on Feb 6, 2015 10:03:12 GMT -6
Manual states A.C. Magneto charging system. I did not charge the battery, but it had enough juice to start the engine, so it should have enough juice to turn on headlight with key turned, right?
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