1981 XS650 SH Problem

BowlingSS

XS650 Guru
Top Contributor
XS650.com Supporter
Messages
1,309
Reaction score
1,920
Points
163
Location
Lawrenceville, GA
Just got my new fuse box and starter up my 750 engine running. It started running right away. I stopped after just a minute of running to check everything. I did this a few times with a fan on the engine. The next time I tried to start it would not start. I checked the plugs and one was a little rich but I am sure that was caused by the oil in the top end. I clean both plugs and checked to see if they were firing. I did wait 30 minutes or so. I had the left plug out and grounded to the cylinder and the bike started with only the right plug in. Made me jump. It seems like it could be the TCI unit or the coil. I did notice a small crack in the middle of the coil. What does everyone think? I think I need to test the coils first. What about testing the tci unit, how do you test it?
Thanks
Bill
 
following :popcorn:
Hopefully it's a simple loose end to find.
Coil? Doesn't sound like it's ran long enough to suspect a coil yet?
Keepng it going up to temperature with that fan on seems like a reasonable idea.
BBK in action !
 
Battery voltage?
Seeing as how an idling bike doesn't charge as well as with throttle on and rpm's around 14k.....add using the starter to get her going instead of the kicker plus the headlight on and you'll start a drain that may take some sitting to bring her back up.
I've got a voltmeter that comes on with the key and a headlight that comes on with a switch. Voltage at idle is around 12v, add the headlight on and subtract around 2v, so idle is around 10v @1200rpm.....1400rpm and we're charging. Other opinions may vary.......
 
I went out this morning and she would not start. I changed the plugs, no help. I took the TCI unit off the bike and opened it up. All I did was spray contact cleaner on both side. Plugged the TCI unit in and it started right away. Mounted the TCI and it is still running. I let it run with a fan for about 15 minutes. Turned off and it started right away. It is a miracle!!! I have to get the seat and taillight wired up before I can take it for a spin. I am going to work on that now.
Thanks guys.
 
When you say "coils", on the 81 there is usually a single coil with dual output. If it has a crack in it...definitely suspect.
 
Sounds like you may have had a poor connection in the TCI unit's connector, and the simple act of unplugging and re-connecting it solved the issue. The plug is located in a bad spot, right along side the battery. It's subject to battery acid or just battery acid fumes and can get all corroded over time. The one on my '83 even needed a few of the crimps in the plug replaced as they had corroded away to almost nothing.
 
Sounds like you may have had a poor connection in the TCI unit's connector, and the simple act of unplugging and re-connecting it solved the issue. The plug is located in a bad spot, right along side the battery. It's subject to battery acid or just battery acid fumes and can get all corroded over time. The one on my '83 even needed a few of the crimps in the plug replaced as they had corroded away to almost nothing.
I did spray the contacts with contact cleaner.
 
Sometimes it take disassembling the whole plug (removing the wires and crimps from the plastic housing) and wire wheeling them clean. Then a coating of dielectric grease and re-assemble.
 
Just to provide the dissenting opinion and I mean no disrespect, I avoid that stuff like the plague, at least on electrical connectors.
Agree. It's a dust and dirt magnet. I'll use, but only as a last resort.
 
Well, I've been using it for many, many years and haven't had any issues. Besides all my electrical connections, I put it in bulb sockets and on the bulb bases, and on the headlight prongs before plugging it in. If it is an insulator then I guess it must get pushed off the contact areas when you plug things in, because I've never had a connection not work because of it. I guess maybe what it does do is seal up the connection and protect it against water and corrosion. I have never found any corrosion on connections I cleaned and coated, sometimes many years ago, that I take apart again now. To each his own I guess. This works for me so I'll keep doing it, lol.

One change I have implemented is pertaining to my ground lugs and eyes that bolt to the frame. After Dremeling them bright and shiny, I coat them with copper based anti-seize before bolting them down.
 
If it is an insulator then I guess it must get pushed off the contact areas when you plug things in, because I've never had a connection not work because of it.
Yes, that's exactly how it works. It does what you say it does, no argument. However, I have both suffered failure and been stuck on the side of the road with someone else's failure because of it. @5twins, your maintenance and preservation skills are extraordinary, so far be it from me to tell you what to do. However, I'm quite adamant about my dielectric grease attitude. I won't be confrontational about anything else. I don't believe. :rolleyes:
Off my soapbox.
 
Dielectric grease....
We used it on cable t.v. connectors outside in the environment, the reasoning was to prevent two dissimilar metals from welding by micro voltages. Brass connectors on a pot metal tap port without it was problematic.
 
Sometimes it take disassembling the whole plug (removing the wires and crimps from the plastic housing) and wire wheeling them clean. Then a coating of dielectric grease and re-assemble.
I agree with 5Twins. My 81 would intermittently cut out. Finally tracked it to the connection as he described. I wound up replacing the entire plug with new crimps. No issues ever since.
 
Like I said, that's a really bad spot there. The reg/rec plug is right there too. Probably the two most important electrical components and their plugs are very vulnerable to corrosion because of their location.
 
Jet, exactly what kind of failure did the dielectric grease cause?
 
Back
Top