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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: IHEnter on October 20, 2015, 01:43:42 PM

Title: Bike Shuts Off While Riding
Post by: IHEnter on October 20, 2015, 01:43:42 PM

Three times now in about the last year my 1985 K100RS has shut off while riding in a straight line on smooth pavement.  The first time was about a year ago and the last two times were last weekend.

The first time it happened, I rolled to a stop on the side of the road and just hit the start button.  The engine cranked but the bike did not even attempt to start.  I turned the key switch off, back on, and tried again and the engine started right up.

The other 2 times gave the same result.

The only clue that I have noticed is that red bulb monitoring light comes on immediately each time the engine has shut off (similar to how it does when you first turn the key on).  Though I can't remember for sure, I believe it stayed on through my entire deceleration and attempts to restart the bike.  I think it only cleared after I cycled the key switch and pressed both brakes. 

The only other thing I've noticed is that all the times it has happened are towards the end of a long day of riding so possibly it is heat related.

Any suggestions on where to start my troubleshooting would be appreciated. 

Thanks
-Ian

Title: Re: Bike Shuts Off While Riding
Post by: johnny on October 20, 2015, 01:56:47 PM

greetings ihenter...

welcome to motobrick.com...

since its acting up while riding in a straight line... id recommend dragging peg in twistyville..

thats prolly all it needs... well that and cleaning up the 4 pin undertank fuel pump connector...

j o

Title: Re: Bike Shuts Off While Riding
Post by: The Mighty Gryphon on October 20, 2015, 02:16:06 PM

Sounds just like the problem I had with my ignition switch.  Except mine would do it at the beginning of the day, either as I was first starting it or after about 15-20 minutes of riding.

Wouldn't hurt to open it up and do a good cleaning.  These switches don't have a lot of force acting on the contacts and it doesn't take much to break the connection.  I'm amazed they don't cause more trouble.

http://www.eilenberger.net/K75S/IgnitionSwitch/

Title: Re: Bike Shuts Off While Riding
Post by: Motorhobo on October 20, 2015, 04:34:55 PM

That happened to me too, once on the NJ Turnpike -- unplugged the ECU, plugged it back in, and off I went -- scared shitless but still moto.

Title: Re: Bike Shuts Off While Riding
Post by: Gio on October 20, 2015, 10:29:07 PM

+1 re ignition switch as possible culprit ... I had similar problem a few years ago, removed/cleaned up contacts and no problem since.

Gio

Title: Re: Bike Shuts Off While Riding
Post by: Motorhobo on October 21, 2015, 07:02:54 AM

BTW I also had an onroad shutdown once due to a faulty start button. I ended up disassembling and bypassing the button and pushstarting on the I-76 north of Philly. Not fun. +1 for taking apart and cleaning anything that has power running through it.

Title: Re: Bike Shuts Off While Riding
Post by: IHEnter on October 21, 2015, 09:10:31 AM

Thanks for all the suggestions.  I will definitely seek out the twisties and also pull the ignition switch apart at my first opportunity and report back on what I find.  It sure sounds like a good chance that is what is causing the problem.

Title: Re: Bike Shuts Off While Riding
Post by: The Mighty Gryphon on October 21, 2015, 09:58:13 AM

Don't be fooled if it looks clean in there.  It seems that it only takes a microscopic amount of dirt or corrosion to make the switch whack.

Title: Re: Bike Shuts Off While Riding
Post by: IHEnter on October 21, 2015, 10:04:25 AM

. . . Sometimes electricity is just a mystery