Plugs not firing

[Dan D]

Hi, just bought a 93 NTV 650 and after two weeks of smooth riding, found that it wouldn't start one morning. The starter motor turns the engine over, but no firing. I pulled out the plugs and they were in nearly mint condition, but did not fire when the engine turned over. Any suggestions? I have a friends broken down ntv I can use for spare parts so am willing to play around with different solutions at no cost.

Thanks,
Dan

[yellowmelos]

could try the the pickup on the right side of the engine ( as looking from the back) or the wiring for it first.
and the connectors to the coil's... also the connections from the off switch on the right hand handle bar

[De Graaf van Salland]

At least this will help you to locate all the various parts:

www.stoeretassen.nl/My_NTV650/Ontsteking/Ignition.htm

Good luck with the fault finding.

GvS

[De Graaf van Salland]

Oct 16, 2010 18:46:57 GMT 1 yellowmelos said:

could try the the pickup on the right side of the engine ( as looking from the back) or the wiring for it first.
and the connectors to the coil's... also the connections from the off switch on the right hand handle bar

Hmmm......
Is the engine kill switch in the correct position ?

GvS

[rj2para (Bisto)]

Side stand down?

Or check the leads from the battery for internal corrosion. That was a problem I had. Along with the side stand

Good luck

Roger

[McF]

Oct 17, 2010 17:19:07 GMT 1 rj2para (Bisto) said:

Side stand down?

If the engine turns over but not fires, it's well worth trying all of the "safety logic":
Side Stand Switch - stand should be up
Neutral indicator - should be in neutral
Clutch Lever - Clutch should be out

don't just check the condition, confirm the switch is doing the right thing (or at least makes / breaks when you move the relevant lever)

It shouldn't take long to rule these variable out but I suspect they aren't the answer. As far as I can work it out, they not only prevent the engine firing, but prevent it from turning over too.
There are conditions when you can start and run eg:
Side stand down but in neutral
In gear but clutch in
a fancy diode controls the signals and whether the bike will run or not.

Have you tried the primary and seconday HT circuits? If there is no sign of a spark to either cylinder, it must be something common to both, so it may be worth checking the plug for the wire coming from the pulse sender.
Follow the heat insulated wire that rises out of the front of the clutch housing and up the frame. Somewhere near the front of the petrol tank on the right side is a small 4 way plug to join the cable into the loom. If this is shitted up it could be your problem. Give it a good clean, ideally with electrical contact cleaner (better than WD40, but that will be better than nothing), then reconnect and try again.
You may need to try mechanical cleaning (eg point of a small flat bladed screwdriver) to scrape off any versdigris.

If you have inclination, it's worth going over the whole loom (even if this fixes the problem) and splitting every cable connection, cleaning up and slapping some petroleum jelly (vaseline) on the contacts