Help, 79SF, sudden power loss....

[ron2830]

it has been running fine, out for a ride tonight, died as I pulled away from light, thought I was trying to start in second...suddenly no power and stuttering above idle. Rolling throttle on and it would finally take off, limped home and got worse. Finally died in driveway and would not restart unless I used choke. Then would not start at all. Supposed to go for ride tomorrow, any thoughts? Plenty of gas, tried petcocks in reserve and prime, but no help. Thanks.

[BLUEJEEPLAB]

Having to use the choke to restart even when warm points to fuel starvation. Any possibilty you got some bad gas? You say plenty of fuel, where? At Petcock? Carbs? I had a similar problem with my XT, it turned out to be clogged fuel line to the carb.

[knewsom]

if it's not a clogged petcock or fuel line, see my quote below.

[Ken Talbot]

Check out the pick-up coil wires. A lot of fuel supply and carb problems can cause similar problems, but they do not tend to come on suddenly. Electrical problems like pick-up coil wires, do come on all of a sudden.

YMMV

[TopCatGr58]

Along the same line of thought, also check out the TIPOVER switch under the tank! Just unplug it and see if it will run. We had a fellow with an intermittent problem during a rally, turned out to be the tipover, unplugged it, and he was able to make his way back from Pa. to Canada!!

Also, check Emergency shut off switch, FUSES. Also, battery, what's its voltage? Less than 10 volts, and the TCI won't fire right! Good Luck, hope you find it and get go for that ride!
T.C.

[ron2830]

It runs again....

.....but not sure what exactly fixed it, did not have time to try one thing at a time and then start it.

Pulled gas tank, fuel flowing freely through petcocks

checked float bowls and all were full of gas, drained them just in case I did get some bad gas, I had run it down to reserve and added two gallons when it started running rough. Maybe water in the bottom of tank?

Checked coils, spark plug wires showed 26K ohm across pairs, primaries showed 1.5K ohms. Noticed the common primaries (red wires) were kind of loose in the connector, pinched the female side down a little and now tight...maybe on to something here.

Spark at all four plugs, also checked all other connectors for tightness.

Fired it up and now it runs just as before.

Not sure what it was, maybe gas but possibly the loose primary wires on coils..

What is kind of weird is the "mid range hesitation" around 5K rpm seems less.

Thanks for all the advice, the adventure continues, off to my ride.

[ron2830]

Forgot to add, pickup coil wires seemed fine when doing physical inspection, tugged on, no stretch to them. Is there a place I can check resistance with a meter to verify pick up coil wires?

Thanks again guys....

[TopCatGr58]

Yes, Ron,

Where the PU coil wires connect to the TCI! See the LINKS section, and look on the second page for Randy's TCI testing and his web site link, I fixed it a while back so it does work, has great info on how to test your TCI, PU coils, etc! Congrats on the fix. Yeah, you're probably right, the primary wires to the coils may have developed some corrosion along with being loose, dropping their continuity, and their power...and yours!
T.C.