Bike cuts out, now won't start

T

Tacforce650

XS650 Member
Messages
25
Reaction score
0
Points
1
Location
New Albany,IN
Took my 1980 650 special out today for the first time. Rode for about an hour. When under hard acceleration it wants to cut out until you find a nice cruise speed and all is well. I park at the parts store and run in for a few. When I come back out the bike wouldn't start. I drained the fuel from the carbs thinking it was flooded. Still no luck. It would backfire when I kicked it so bad that it would k och the carbs off of the rubber grommets that they sit in. Any suggestions? My bruised foot would appreciate it!

Side note: PF Flyers, not good for kick starting.
 
A bit more info would help. Like mods as in carbs, exhaust, air filters, ignition.
It sounds like the ignition may be set a bit to much advanced.
One more thing NEVER ride in anything without a hard sole and good ankle support. Or risk a broken ankle.
Leo
 
No mods to the bike. Could it have jumped time? And if so could it have messed anything up? How hard are these bikes to put back in time? I'm a car mechanic but I have no experience with motorcycles.
 
I'm guessing coil, or plugs, or plug wires. Under WOT, the ignition has to build to higher voltage to spark thru higher pressure, less voltage for cruise/lower pressure.
 
Last edited:
Can that cause the backfire on kick start? It has brand new plugs in it and are gapped properly. I did notice that when I pulled the plugs that the left side was carboned up after only a little riding and the right side was clean.
 
Sounds like you'll be chasing 2 things now. I believe you have one of those single coil to 2-plug ignitions. Fouled plug may affect both sides. Real problem may be left side richness. Clean/replace plugs to confirm.
 
With the 80 model it had the TCI. The timing is controled by the TCI box. There is a magnet in the rotor. This magnet passes the pick ups as the engine turns over. This sends a signal to the TCI box. The TCI boxe uses this signal to tell what the engine position is and rpms. The TCI box uses this information to tell when to spark.
If there are dirty connections in the circuits then the information might not be good enough for the TCI.
This can cause the timing to be off. I might go through all the connections from the pick ups to TCI box. Make sure all are clean and tight.
Do you have a repair manual? On page 181 of the Clymer book is an ignition trouble shooting guide. It tells how to test the pickups and coil. It has a chart telling how to check for other problems and what to do to fix. On page 150 of the Haynes manual is a simular guide.
My guess is bad connection, the TCI box, the Pick ups, If the trouble shooting guoide leads you to the TCI search this site for TCI box fixes.
Another thing is battery voltage. The TCI is somewhat voltage sensitive. It needs a fully charged battery to perform its job. Fully charge your battery and see if that helps. If it runs ok with a fully charged battery, it means your charging system isn't charging as well as it should. You need to troubleshoot your charging system. It could be just worn brushes. Check them first. They put them last in the book. The book calls for 1/4 inch minimum length but 3/8 inch is a better spec. They don't cost much so you can just replace them. Do the rest of the checks in the book.
If you browse through the XS650 TECH section of this site you will find a trouble shooting guide for the charging system.
You will also find a carb guide. Once you get the ignition and charging systems working well you might need to go through the carbs.
Leo
 
The TCI (ignition) was a good ignition, but its getting really old and that could be causing your problems. Its possible that the trigger magnet, found on the alternator rotor, has weakened with time. You could try disconnecting the rectifier/regulator connector, and then try starting. If it starts and runs, just using the battery, then you need to buy one of those Radio Shack super strong magnets. Some lads have had success gluing a new magnet on top of the existing magnet.

If the problems lies with the TCI black box, there's no way to trouble shoot it other than replacement with a known working TCI.
 
I'm gettin 23000 ohms through my secondary windings of the ignition coil. The primary is in spec. Connected to either end of the spark plug wires is how I understood it. So it's looking like a coil issue. Where's the best place to get a stock replacement?
 
That actually sounds correct. The ratio of the primary/secondary resistances closely match the voltage step-up produced by the coil. Suggest re-reading posts #10 and #11.
 
Man, I'm getting clobbered out here, over 20 'net' crashes today, so make this short. If each side of your coil wires has a 5k ohm plug cap, then your readings for the coil puts you in the ballpark. Also, try the google search of this forum using "secondary"+"resistance". Keeps crashing on me, maybe you'll get lucky...
 
Tacforce650 said:
I'm gettin 23000 ohms through my secondary windings of the ignition coil. The primary is in spec. Connected to either end of the spark plug wires is how I understood it. So it's looking like a coil issue. Where's the best place to get a stock replacement?
Click to expand...

1980 ignition coil has 13K secondary winding. Add 2, 5K caps, and you get 23K ohms. Your coil should be good.
 

Similar threads

Fingerscrossed
Engine cutting out / dies on throttle
2 3
Replies
41
Views
2K
Fingerscrossed
Fingerscrossed
Batterylizard
‘79 xs650 won’t start ..backfires out of left cylinder on kick
Replies
8
Views
846
5twins
5twins
M
Not starting after a few small maintenance jobs. I’m stumped.
2
Replies
33
Views
1K
Jim
Jim
S
Hissing out of left carb and then bike dies.
Replies
13
Views
900
Boneheads47
B
H
has compression, spark, and fuel but won't fire / start - cam chain issue?
2
Replies
36
Views
2K
Jan_P
J
Back
Top