SP 1000 electrical gremlin

[ukdavo]

Hi folks - I have a 1979 SP 1000 with a weird syndrome. I think it is probably a single relay causing a variety of problems. Bear with me please, I'm a (gasp) BMW guy & novice w/Guzzis.
1) Gives me a starter relay click unless it has just been charged. New battery, takes and holds a charge fine. After charging it will start just fine, and run fine - for a while. Then it will intermittantly cut out and run on one cylinder. If I stop & pull a plug wire it seems like I'm getting spark, and both cylinders start firing again. If it stalls, sometimes it won't turn over on the starter again UNLESS I put the key in position 2 (aux) and then switch it back to position 1 (start) while it is cranking.
2) What I've done: New battery, new wire core plug leads, reversed plug wires (made no diff). I'm not positive which cylinder cuts out; seems like the Left at the moment.  If I take a jumper wire direct from the battery to the starter solenoid it ALWAYS cranks fine. New plugs, of course.

So - any ideas would be much appreciated. I'm in rural E Oregon, far from any service possibilities. Thanks, David

[charlie b]

Have you put in a new starter relay? 

The cutting out part would worry me a bit more.  Are you sure it is one cylinder and not just a random spark?  I'd also try cleaning the switches.

[fotoguzzi]

UNLESS I put the key in position 2 (aux) and then switch it back to position 1 (start) while it is cranking.
 

I think you can take apart and clean the ignition switch.

[nunzio]

Do you have the only the key in the ignition and not a bunch of other stuff on a key ring hanging on?

run it with only the key in it.

[ukdavo]

Thanks for the answers (so far). No, I haven't swapped out the starter relay. It looks hard to get to. & I'm kinda lazy. Only one key in the switch. I guess I'll try to pull the starter relay. Could that relay affect the ignition? Appreciate the help very much. David

[JoeW]

Most likely is a bad ignition switch, could be a bad starter relay too but, the relay will not affect running.

[Kiwi_Roy]

I think it's probably the ignition switch but there's a simple wiring change that will improve the starting
Power up the start relay contact directly from the battery through a fuse. The coil feed stays through the switch.

http://www.thisoldtractor.com/guzzi007/schematics/1978_V1000_SP.gif

[guzzimike]

Has the motorcycle  been retrofitted with an aftermarket Electronic Ignition, such as Dyna ..?


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[ukdavo]

Sounds like there's some consensus that I should pull the ignition switch & clean it, maybe replace it. To answer the question re: Dyna fitment; no, the ignition is stock. I'll post the result of the sign switch inspection. Thanks again, folks. David

[swalker]

David,

   If you are running stock points, make sure your condensers are tight. I had one come loose on my V7 Sport once and it caused spark problems. Make sure they are getting a good ground.
   Other than that, I would look at the ignition switch as mentioned.
Good Luck.
swalker

[ukdavo]

Thank you mr walker. David