going crazy

[capymotiv]

History: 88 full power, kickstand switch clipped, new cop's (Jon Harris), New ignateck (Sean Morley), exhaust drilled, new carb diaphragms, good AGM battery, charging system working, connectors checked for shorts,cleaned and greased. Pulling ign switch and start button to check and clean today just because.
Original problem was rear 2 cyls would not fire. replaced cdi with Ignatek. Bike ran great. Rear 2 cyl drop again couple weeks later while out riding. Pickups tested fine per book. Cleaned, tested and greased all connectors (per Seans rec). Bike ran great again. Today, taking old lady to work, stop at light and can feel it drop the back 2 cyl again and I notice the tach is dead. Bike stalls out. Restart it and tach is working again with bike running fine. Dropped her off, talk to buddy couple min tops. Start bike, go to take off and back 2 cyl and tach are dead again. Hit a bump and every thing is normal again. Can a r/r cause this? Thinking it's gotta be a wire or something loose or broken to be this intermittent. Any ideas? I am fresh out if not the switches.
Sorry so long.

 

[Fire-medic]

Time for the 'wiggle test.'

You probably have a loose connection, or one that's also corroded. The time-honored method is to start with one aprt of the wire harness, and to flex it, to see if you can duplicate the cyl's dropping due to your manipulation of the wires. You have to do it systematically. Since it's the ignition, I would concentrate on the wires that service the cylinders which are not fully-functional. You should also check the connectors to make-sure the spades and terminals are tight, and that you don't have any disintegrated wires where the crimp on the wire is for the quick-disconnect, whether it's a single wire for a molex-type ganged wire-set, where a female plug accepts the male plug into it for multiple wires. These on cars, bikes and trucks are usually polarized so they can only plug-together in one direction.

There's a simple tool you can get at any good auto parts store, for removing individual wires from those nylon communal (multi-) wire blocks. Yes, theoretically, you can use a small screwdriver to release the connector from the nylon block, but it's much-easier and faster, and 'way-less frustrating to use one of those cheap wire-removing tools. To ensure that you don't make any mistakes, make sure that you just remove one pair of spade/female connectors at a time from the nylon block, and that the wire color code is identical on both sides, because sometimes it isn't! Look for green corrosion or a loose connector, hanging by a couple of copper threads at the male or female (M or F) brass connector. I've had either a M or an F terminal look like it's well-crimped, but inside that first inch of PVC wire insulation, the strands of copper wire have nearly-all broken, leaving only a few to carry the current. Grabbing-onto a suspect individual connector and giving it a bit of a pull, may suddenly result in the connector having those last couple of copper strands snapping. No big deal, you just strip-back the wire to good strands, and use a rosin solder to solder back-on the connector, or a new one if you can find them in the right size. You will easily recognize the difference between a broken strand of wires, save for a coup[le, versus a well-fastened wire with all strands intact and not corroded/broken.

 

[one2dmax]

You might also check the vacuum sensor. Seems like we've had a rash of customers with them going bad lately.

 

[maleko89]

My bet is the pickup coils. There are two on early models, one fires the front cylinders and the other the rear. Pickup coils can test fine and still be bad.

Mark


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[capymotiv]

Vacuum sensor was upgraded (soldered and heat shrinked)with Seans Ignatek kit. Thinking of getting a set of pickups from Sean and finding another harness and just being done with it. Ign switch and start button were in good shape. Just tired of throwing money at it.