i need some help with this problem '92 K75RT

my 1992 K75RT with 79,000 miles has an intermittant problem; i've owned the bike over 10years, in those years maybe months apart, and at speed, the bike would just die, dash lights stay on, just goes dead; pull of side of road, it always restarts.........now lately it does it a bunch maybe every mile or two.....just changed plugs and wires.......there is no sputtering, no backfire, nothing, just dies. makes me think ignition? boy do i need some ideas.....has new fuel filter......

any suggestions helpful, i hate to take it in to the dealer without the problem being permanent so as to troubleshoot easier.

thanks,
carney
carneyrobertson@yahoo.com

does this problem sound like a solid state ignition failure? never remember the bike doing this when it was stone cold

I read in a couple of other threads that these types of problems can be caused by loose connections in the wiring harness, under the tank. I'd take a look there first.

The next time it dies and won't start, listen for the fuel pump to continue to run for a couple of seconds after you release the starter.

If not, the tank connector under the right battery cover is the 1st thing to check.

One of the things I would try is to disconnect the ECU under the tank, then clean the connectors and replace. This seems to be a fairly common problem on these older K bikes. Mine did this but never got as bad as you describe. Cleaning and reseating the ECU connection cured it.

I had a K100 that had similar problems, the connector going to the ignition box under the tank was loose. I reseated it & wrapped a big tye wrap around the ignition box to hole the plug firmly in the box. Never happened again. I have read about doing this in another thread also.

I think every one of the above ideas are good ones, as well as a few others I can think of. But to make the task easier I would try to isolate whether the problem is the loss of ignition or the loss of fuel.

Because it happens so often the first thing I would do is remove, clean, and re-seat the ECU plug. Beyond that I would determine whether it has any spark next time it quits. I would use an inductive timing light - just clip the pickup around a plug wire, power the light, and crank the engine. I just shine the light into the palm of my hand to see if it is flashing. If it is I have spark. There are other testers but this is the easiest.

NOTE: A bad spark plug or plug wire could result in the system working as far as the coils, but failing to fire the light - but that would be on one cylinder only, not all of them at once.

If it dies and still has spark then strongly suspect the fuel pump wiring and connections.

Carney,

I had a similar problem with a perfectly running Honda 125. I'd be tooling down the road and the bike would just conk-out.

The culprit ended up being a shorted emergency shut off switch. It looks like you live in Louisiana where there's a lot of humidity.

You may want to add this to your list of things to check.

PGlaves said:

I think every one of the above ideas are good ones, as well as a few others I can think of. But to make the task easier I would try to isolate whether the problem is the loss of ignition or the loss of fuel.

Because it happens so often the first thing I would do is remove, clean, and re-seat the ECU plug. Beyond that I would determine whether it has any spark next time it quits. I would use an inductive timing light - just clip the pickup around a plug wire, power the light, and crank the engine. I just shine the light into the palm of my hand to see if it is flashing. If it is I have spark. There are other testers but this is the easiest.

NOTE: A bad spark plug or plug wire could result in the system working as far as the coils, but failing to fire the light - but that would be on one cylinder only, not all of them at once.

If it dies and still has spark then strongly suspect the fuel pump wiring and connections.

Click to expand...

I think this is a great suggestion. Knowing whether its fire or fuel sends you in the right direction.

The timing light test I described in post #8 is also very effective in troubleshooting what seems to be a misfire or irregular running. By switching the light from plug wire to plug wire you can watch the sparking while the engine is running, and see the ignition break up at various RPM or running conditions, and isolate it to which cylinder is affected.

Great suggestions. Pauls test is execellent.

Even easier to do if you can find a neon ignition tester. Champion used to make these - the size of a ball-point pen, a plastic housing with a metal end, and neon light in the housing you can watch. When you touch the end to an ignition wire - the ignition pulse will make the neon light flash - not too bright. If the wire has a break or "leak" in it - as you pass the metal end over the wire - when it gets to the break in the insulation the neon bulb flashes very brightly. Handy tool that's easy to carry on your bike. Dunno if these are still made - but a Google might turn one up. Mine is about 40 years old (one of the first tools I ever bought actually..)

EDIT: - http://www.nextag.com/LIS19380/products-html?nxtg=2b760a500503-77A9DF7A433E6096 - Google found one that looks just like my old Champion one - $1.19-$15.



Another possible failure point is the ignition switch, and this is fairly common as the bikes get older. It can be intermittent - and kill the engine, then reconnect and the lights appear to still be on. Test for it is easy - a garage test. Walk to the bike, turn the ignition on, watch the instrument warning lights. Gently wiggle the switch in the on position. If the lights flicker - the switch needs cleaning. If so - get back to us and I'll point you to an illustrated guide to disassembly and cleaning the switch.

One other suggestion - put year/model of your bike in the thread title. This helps people who might have something to offer spot your thread. And it will help people later who are searching on a problem spot your thread. Win-win as they say. I've added it for you.

Good luck..

deilenberger said:

EDIT: - http://www.nextag.com/LIS19380/products-html?nxtg=2b760a500503-77A9DF7A433E6096 - Google found one that looks just like my old Champion one - $1.19-$15.

Click to expand...

Be careful of that first link for $1.19. You're signing up for something that costs you $19.99 after 7 days and is recurring.

You used to be able to find just the neon bulbs at RatShack, but they no longer carry many parts. The bulb is NE-2 or NE-2H. If you've got an electronics friend, there are prolly a few of them in his/her parts drawers. You don't need more than the bulb. Just put it in proximity to the ignition wire and the spark will ionize the gas in the bulb. Just make sure the pigtail leads on the bulb are not shorted together when you do this or the bulb won't light up.

Tom, thanks for the heads up.. the next two links on the page are reputable - Sears and Buy.com..

Wonder if Radio Shack still carries neon bulbs? It seems so old tech and non-digital (they have been phasing out a LOT of parts in the past few years in favor of electronic toys and gee-gaws..)