Topic: 2-3 cutting out issue is back

[Bankerdanny]

Right before I left on my trip I experienced the 2-3 cylinders cutting out on my 750F1. I pulled the carbs and double checked the float levels, confirmed my valve clearances, and double checked the timing and point gap.

I thought it cleared up, but then on the first day of my trip it came back. I stopped at a gas station and swapped out the 2-3 condenser for a spare, which seemed to do the trick and it performed just fine for the remaining 1800+ miles I was gone.

Tuesday I decided to ride to work and about 5 miles into the trip I lost them again. I limped into a neighborhoods, parked and took the L the rest of the way (thank goodness for Chicago public transit) and then limped it home.

Last night I swapped in the spare 2-3 coil I picked up on the trip. The bike started right up and was running solid, but after about a block, 2-3 stopped working again.

I am at a loss about what to do here. the fact that it is the pair that I keep losing indicated ignition rather that fuel, but I have replaced all the 2-3 components except for the points. I have 2 spare points setups, so I can swap them, but they are just a mechanical switch, I can't see why they would be the cause of my issues.

I would love some thoughts on how to trouble shoot this.

[Don R]

 These types of problems are a pain, especially since you've done the right things so far. Double check the 12 volt wires and especially the connectors at the points. I found a broken wire in the insulation in a headlight bucket once. It could happen to the points wire. Maybe even make up a jumper wire to temporarily replace the 2-3 points wire?

[TwoTired]

Check for points function when it quits.  Points open should have 12V across the them.    Closed points should have zero V across contacts.  The moving arm contact must be insulated from the frame.  Look for a short there. Or a failure of the insulation. Or, try some spare points.

What brand points?  What brand condensers?

Have you cleaned the contacts?  Are you using low ohm coils?

Cheers,

[Bankerdanny]

Check for points function when it quits.  Points open should have 12V across the them.    Closed points should have zero V across contacts.  The moving arm contact must be insulated from the frame.  Look for a short there. Or a failure of the insulation. Or, try some spare points.

What brand points?  What brand condensers?

Have you cleaned the contacts?  Are you using low ohm coils?

Cheers,

The points and condensers should be the originals, so TEC. My coils are stock and I replaced the plug boots with fresh NGK's last year.

[69cb750]

Points, condensors, coils
Condensors and coils can fail from age, coils can alternate between working and failing when coil is old and heats up.
I have new spares, points plate first, coils second.

[seanbarney41]

Just about has to be a loose connection somewhere...first place i would check is the black and white wire powering the 2-3 coil.

Remember when we were riding and your bike would shut off altogether?...what did that end up being?

[Bankerdanny]

Just about has to be a loose connection somewhere...first place i would check is the black and white wire powering the 2-3 coil.

Remember when we were riding and your bike would shut off altogether?...what did that end up being?

I found a short in the harness that was causing that.