Went to start bike after sitting for about a week or so .Bike started and then cut off . First thought was the carbs of course. Pulled them and went through. Same thing .Was running 8 mm suppression core wires .Bought copper core and new plugs. Same thing . So I ordered a new coil. A lower ohm coil. Still no spark . Maybe ignition unit or rectifier???
-
Enjoy XS650.com? Consider making a donation to help support the site.
XS650.com receives a small share of sales from some links on this page, but direct donations have a much greater impact on keeping this site going.
No spark
- Thread starter TGOOD
- Start date
My physic powers are weak this morning, what ignition?
As always testing is key, random parts replacement is the long hard $$$ way to find a problem.
As always testing is key, random parts replacement is the long hard $$$ way to find a problem.
So it's a heavily modified bike running a TCI? I'd start with checking grounds very carefully. Same for +12. A 12 volt light bulb like from a tail light or turn signal with some leads and alligator clips makes a good voltage tester, helps show the difference between a GOOD 12 volts and weak connections.
Mr. gggGary, should I have 12.3 V on both sides of coil ? I found out that my lights hooked up to the positive side of the coil I guess was take from ignition . Of course ,after I purchased a new coil and installed . Bike ran great for a couple days and went to fire it up and it started then cut off.
one side should be 12ish, other side should vary when motor's cranked. Not quite clear on what all you are saying in your last post....
no
I have a 3.3 ohm XS performance green coil .I have 3.6 ohms terminal to terminal .I have 15.7 from spark plug wire to spark plug wire with NGK boots off on 20k setting. I have no reading on one boot and .94 on the other on 20k setting .is coil , wires , and boots ok ??
When testing low resistances, test your leads first. Short them together, take a reading. Then, subtract that reading from your coil measurement. For example, if the shorted leads show 0.3 ohms, subtract that 0.3 from 3.6, and get 3.3ohms.
Set your meter on the 2k scale and retest the plug caps. You may have 2 different caps, one at zero ohms, the other with the internal resistor...
Prisondawg
XS650 Addict
How are the connections at the TCI box. If there is power to both sides of the coil, it seems like either the coil is bad which probably wouldn’t occur unless you were running the bike with one or both of the wires disconnected . Or if you have continuous power running to them for example leaving your key on, or wiring them so that power is constantly running even with the bike off. If the coils are new. I think it would have to be a TCI box issue. As that box tells it when to fire. It seems like it’s not telling it to fire. Some corrosion , a disconnected wire, or wires that are mixed up might be at play. Hopefully the box itself isn’t bad, there has been luck in repairing them. There are threads outlining that process. The only way to test that really from my knowledge is to swap it out with a box that you KNOW works.
Wulfbyte
XS650 Addict
Check the small magnet on rotor ,it goes weak and the pick ups won’t detect it and will give little to no spark, you can epoxy a new rare magnet,from radio shack, on top ,I actually put two on mine had to put small washers under pickups to raise it a little for clearance but with one there is plenty of clearance! Was having same problem and it was on a new o.e.m. rotor! You might be having the same problem, hope it is ,it’s an easy fix and mine has been doing fine ever since! But I am going to go ahead and get a brand new rotor soon! Hopes this helps a lil, good luck!
Yeah, those caps, good design, but they do go bad.
Just for kicks, unscrew one of those connectors, pull the insides out. There's a lot of connections being made in there. 30 - 40 year old caps can be filled with corrosion. That innermost connection can get too corroded to even be cleaned to make contact.
Scott
Oh, what size wire is recommended for the coil? You should probably be using non-suppression metal core wire and NGK caps.
I've tried automotive caps, never liked the connections at wire or plug, and most are not a water resistant fit on our smaller dia. plugs.
Scott
You can use 8mm wire, depends on what size the coil is designed for. My NAPA, remnant of an old "speed shop", stocks 7mm and 8mm metal core wire, nice silicone stuff, sold by the foot. Then the cap has to match the size of the wire. Some NGK caps are designated for 7mm or 8mm wire, seems like a problem getting the wire centered if using 7mm, to me.
Yeah, mismatched coil, wire and caps could very well cause no spark.
Scott
Yeah, mismatched coil, wire and caps could very well cause no spark.
Scott
