81 KZ750H LTD No spark

wrote:

Interesting, well it seems I don’t have speedometer or tachometer. Both seem to be cable driven and I have confirmed the tach cable has no movement during throttle so I guess that the speedometer is the same? 

If they are both mechanical, the tach should have a spinning cable going to the front of the engine, and the speedometer will have a spinning cable going to the front wheel. 

The tachometer should indicate RPM anytime the engine is running.

The speedometer should indicate speed when the front wheel is moving. It shouldn't be affected by the throttle.

I apologize for the confusion, I meant the tach was unaffected by throttle. Neither are spinning, does anyone have a schematic or video on disassembly of both? I’ll have to take both apart and see why neither spins

There are some posts here on how to rebuild the gauges, but it's quite involved and requires some jigs to get them back together looking good.  Martin CSR may chime in with some decent links on the subject.  You might get more views if you start a new topic for the gauges.

Well it’s not actually the gauges, it’s the cables not spinning. So I hope to not have to pull the gauges apart just yet. 

Have the cables been removed? If so, it may be that they were not fully seated when reinstalled. They could also be broken. The speedometer cable will turn only when the front wheel is turning.

Well not removed by me. I just picked the bike up a few weeks ago now so not totally sure what the history is. One question, if I pull the tachometer cable off the block, will it be one solid piece or will I have to worry about pieces falling into the motor that shouldn’t be there? Probably not going to get to the speedometer cable tomorrow morning so one thing at a time.

Ahh, you meant take the cables apart.

There should just be a knurled collar on the end of the cable housing at the block.  You just unscrew that with your fingers and the cable and housing should just pull out.  Nothing will fall into the block.

Same thing at the wheel for the speedo cable.

 

I did this this morning, the tachometer cable was very rusty at the bottom and had a square drive piece that combines the 2. So I put the piece back in the block and spun the motor over and it spun so I think the tach cable has rusted to the point it won’t spin. Then I pulled the front shaft out of the wheel and confirmed I had movement by moving the gears manually with a screwdriver and I had movement on the output shaft of the speedo gear but still no movement at the other side of the cable so I guess I need both new cables and that Shiism get those to function. Now on to diagnosing the fuel stop light that stays on and no turn signals and the bike should be functioning at top notch after that 

Well I fixed my carb issue and now I have an intermittent no spark issue. Not sure what it is but if I start to diagnose it, find nothing, and plug it back together, it will spark. But then I’ll try to put it all back in place so it will be rideable, it doesn’t spark anymore. Any ideas?

I have narrowed it down to the pickup coils. I’ve got no spark on cylinders 2 & 3 consistently  and 1 & 4 intermittently. So after playing around with continuity and making sure wires did not become disconnected, I tried the bench test on the bike, where you will the pickup coils and trigger them manually with a screwdriver, and I get spark on 2 & 3 and 1 & 4 every time. But when I reinstall it, back to no spark on 2&3 and only spark on 1&4. 

I apologize for the spam posting but it’s just information I think could help in the diagnosis. 

I noticed there was a bigger gap in between the 2&3 pickup coil and the rotating piece of metal that is on the crank. This is compared to the 1&4 pickup. I suspect the gap is too large to trigger the coil thus no spark but when I do it manually with a screwdriver, it sparks fine. Is there anyway to bend the coils and close the gap? 

You might get some reduced gap by bending the pickup frame, but I doubt that is the problem.  Once spinning from running, there should be more than enough signal to fire.

I suspect this intermittent behavior goes back to the coil polarity debate.  That is, when you didn't have spark, then moved the wires, and then had spark.  I suspect there is a wire issue somewhere in the 2-3 circuit.  Are you still using a Wells DR-100 with 1.25v W terminal for both igniters?