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Old 10-21-2014, 09:56 PM   #1
acetycholinsterase OP
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Joined: Jan 2011
Location: The lovely and picturesque Seatac, WA USA
Oddometer: 6
'83 R80 G/S stops running for no Apparent Reason

Hi All,

I have an '83 R80 G/S. It starts quick, even when cold and runs well. from time to time, the engine loses power quickly (you open the throttle but there is no power) and in less than a minute it stops running altogether, even though the ignition stays on and there is plenty of fuel, spark, etc. As if you've run out of fuel but you haven't
Trying to start it, just runs down the battery. No cough, nothing.

Sometimes it happens 1/2 mile into a ride, sometimes after 20 miles. If I let it sit for a 1/2 hour or more and try to start it, it starts right up as if there were no problem. I've had to pull to the side of the road but haven't been stranded (yet).

Most puzzlingly, I tried to start it 3 days ago after it had been sitting in the garage all summer.
The engine turned over, ignition was on, choke open--but NOTHING, no cough, no catch. I put it back into the garage. Two days later, I tried to start it again, it started right up.

This evening, I pulled the tank and looked at everything electrical--voltage regulator, plug wires, coil, relays, ignition control module, battery connections. There was a normal amount of dirt but no corrosion or loose connections. All other electrical stuff (lights, signals) works fine. I pulled off the bosch ignitional control unit and plan to take it to Ridewest (bmw dealership in seattle) to see if they will test it for me, but basically I have no clue as to what is wrong. If it is the ICU, I planned to replace it with an enduralast.

If you have a SWAG you would like to share, I would love to hear it.

cheers to all advriders and enjoy the fall weather!

Matthew
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Old 10-21-2014, 10:02 PM   #2
_cy_
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could be fuel or electrical .. but probably is hall sensor failure located inside your beancan.

when bike dies .. have a can of starter fluid handy. spray starter fluid a good shot on both carbs. this will eliminate fuel as your problem for a few seconds.

unless your plugs are fouled out ... if lack of fuel is the problem with a shot of starter fluid your bike should start up and run for a few seconds.

intermittent electrical is majorly fun!

follow link in sig about changing to beancan with points. thread will also contain other info .. other links in sig will provide testing proceedures for your hall sensor along with how to rebuild info.
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Old 10-21-2014, 10:17 PM   #3
acetycholinsterase OP
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I haven't checked the Hall sensor--can it be tested with a multimeter? I'll check out the links.

cheers,



Quote:
Originally Posted by _cy_ View Post
could be fuel or electrical .. but probably is hall sensor failure located inside your beancan.

when bike dies .. have a can of starter fluid handy. spray starter fluid a good shot on both carbs. this will eliminate fuel as your problem for a few seconds.
.
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Old 10-21-2014, 11:09 PM   #4
Mark Manley
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I have had two Hall sensors die on me with similar symptoms before they expired, I think the only test is substitution.
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Old 10-22-2014, 12:19 AM   #5
Warin
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At this staged it could be anything..

At one point you say you had spark and fuel and it still stopped... was it still stopped after those tests? And how did you test?

------------------
Could be lack of spark - you need to test once it has failed and if the tests passes then confirm the bike still does not run.

This could be due to the hall sensor failing or the ICU over heating due to lack of heat transfer paste to the heat sink.

-----------------
Could be fuel .. Place a large empty ice cream container under a carby float bowel .. remove the float bowel and check that say a liter or two drains out from the carby quickly without stopping .. should be a consistent flow.

Could be caused by dirt in the fuel line, petcocks or the air bleed to the fuel tank being blocked.

==================
YTou missed an opportunity when it did not start in your garage. An opportunity to find out the cause.
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Old 10-23-2014, 01:25 AM   #6
Wirespokes
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Sounds like the hall sensor to me.

One of the tests, if I recall correctly, is to turn the key on - if it coughs like it wants to start, but is dead while cranking, it's the hall sensor.

You have to be careful with this one as there can still be a spark when the plug is pulled and tested, but it won't be at the right time. So don't think that since there's spark it's not ignition.

There's also a test for the hall sensor. With front cover off, disconnect the plug from the sensor. Three terminal plug. Check to be sure, but I believe it's the center contact - when it's grounded (ignition on) the plugs should spark.

The hall sensor is plastic which deteriorates over time and heat cycles. I've seen them where they still work, but have come loose from their mountings. Depending on how the plastic breaks determines failure symptoms, but once they get to this point it doesn't take long to fail entirely. I wouldn't trust the bike till this gets sorted as it could leave you stranded next time.
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Old 10-23-2014, 04:15 AM   #7
Bill Harris
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And remember, if it's an intermittent and apparently heat-related, it could also be the heat sink paste on the ICU. Or, as WS suggests, a Hall sensor on the way out.

Electronic ignition can be reliable and trouble-free, but it's not set-it-and-forget-it. I does need maintenance and when it does go, it goes with finality.

--Bill
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Old 10-23-2014, 06:41 PM   #8
supershaft
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It does sound like maybe a halls sensor put are you saying it has spark when it doesn't run? If so, it's not the halls sensor. It's easy to test. It very well could be a crack-O-matic gray coil.

You can test a halls sensor bad with a LED light but like anything else electrical, you can't really test them good.

The ICU heat paste maintenance myth? It's pure urban legend. Invented by a certain type airhead. Those ICU's work perfectly without heat paste maintenance on tons of different bikes and cars besides airheads. BMW K bikes for starters.
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