Author Topic: Coil resistance (Read 4068 times)

Kentish · « **on:** 26 June 2016, 02:39:02 pm »

Hello everyone

So, I am working through the issue my trusty fazer has developed,poor idle and jittery pulling away. More so when hot. I have changed plugs so far and that's not work. I have checked the plug cap resistance as per the manual and the are all under the 10k the workshop manual states. More like 9k. Also the primary coil resistance is within spec at 2.5 but I just can't get a reading on the secondary coil resistance. Is this the issue? I thought a no secondary resistance reading would cause the bike not to start at all? Mine starts and runs its just poor idle and jittery pulling away. Really bad the hotter it gets.. HELP!!!

slappy · « **Reply #1 on:** 26 June 2016, 03:18:56 pm »

Could the resistance be going out of spec when the coils get warm?

Kentish · « **Reply #2 on:** 26 June 2016, 03:31:23 pm »

That's what I was thinking. I just can't get a secondary coil reading though that would suggest a bad coil. The workshop manual doesn't say check both coils though only 1&2 cylinder coil

Kentish · « **Reply #3 on:** 26 June 2016, 04:01:27 pm »

This issue is deffo only when the bike starts getting hot. When cold it runs fine,

Carter · « **Reply #4 on:** 26 June 2016, 06:38:14 pm »

Sounds like the insulation on something is breaking down when it's hot. May be worth checking the pick up too.

Bretty · « **Reply #5 on:** 26 June 2016, 06:45:55 pm »

Is there no issue at all when cold?
Can you not determine which cylinder the problem is by the temperature of the down pipes? Then eliminate the spark plugs and caps by swapping them around?

Kentish · « **Reply #6 on:** 26 June 2016, 09:31:55 pm »

Well I rode it home today and its fine. All I have done today is unpluged the heated grips and took all the plug caps off and pushed them back on.I also unscrewed them and screwed them back on. The problem has gone for now...Its bizzare

His Dudeness · « **Reply #7 on:** 26 June 2016, 09:40:43 pm »

Did you change your spark plug caps?

Kentish · « **Reply #8 on:** 26 June 2016, 09:59:52 pm »

na i didnt

Fazerider · « **Reply #9 on:** 27 June 2016, 12:56:22 pm »

Have you trimmed the leads? The end bit where the plug cap screws in gets damaged which is why you eventually need to chop a centimetre off to get contact with some good copper.
If there's a break you'll get no continuity when you do the resistance check, but the coil can still generate enough volts to jump the gap. The trouble is it reaches a higher voltage in order to do so, hence it either starts tracking down the outside of the plug cap or breaks down the insulation internally and causes a short in the coil itself.

BBROWN1664 · « **Reply #10 on:** 27 June 2016, 03:02:29 pm »

Are you checking the resistance from plug lead (take the cap off) 1 through to 3 and 2-4? They are linked and act as an earth to each other.

Kentish · « **Reply #11 on:** 27 June 2016, 10:23:29 pm »

Quote from: BBROWN1664 on 27 June 2016, 03:02:29 pm

Are you checking the resistance from plug lead (take the cap off) 1 through to 3 and 2-4? They are linked and act as an earth to each other.

No I was doing it as per that photo above.

BBROWN1664 · « **Reply #12 on:** 28 June 2016, 10:08:46 am »

Kentish - That is lead to lead if you are doing it properly.

Kentish · « **Reply #13 on:** 28 June 2016, 06:57:29 pm »

So your saying put the red multimeter probe into the plug wire 1 and the black probe into plug wire 3?

BBROWN1664 · « **Reply #14 on:** 29 June 2016, 08:53:51 am »

Each coil connects to two spark plugs. If I recall correctly, they are 1 & 3, 2 &4 but I may have got that mixed up with another vehicle.

Basically, connect to the two thick wires from the coil.

Kentish · « **Reply #15 on:** 29 June 2016, 07:12:01 pm »

Mine seems to have stopped this problem altogether at the moment. I don't no why though I have put a new air filter in it also which has made it run a lot smoother

Also you are right mate re 1-3 and 2-4 just been to check

Millietant · « **Reply #16 on:** 01 July 2016, 12:32:32 am »

That's weird, I have a set of Fazer 600 coils in my hands right now and they are marked 1-4 and 2-3.

Also, when checking the coils on our sons 03 Foxeye earlier today, one coil definitely feeds plugs 1-4 and the other plugs 2-3.

It looks like we have a dodgy coil - bike running very rough, no fuel issues, 4 new plugs, but removing plug caps 1 or 4 when it's running makes very little difference, removing the caps from either 2 or 3, causes even further missing. Hence, I'm thinking dodgy coil (first thing I could think of that would affect plugs 1 & 4 simultaneously). Will put replacement coil on tomorrow - hoping its what's wrong.

BTW, this is the very first mechanical/electrical issue we have had with either Fazer (we've had the 1000 for 13 years and the 600 for nearly 5 years).

Kentish · « **Reply #17 on:** 01 July 2016, 08:46:46 pm »

I would love to tell you what was wrong with mine but its stopped doing what it done..

I have purchased a set of new plug caps for it anyway. NGK ones. I have noticed they are 5k resistance not 10k like the standard ones. Will this cause an issue?

Fazerider · « **Reply #18 on:** 02 July 2016, 08:58:18 am »

Quote from: Kentish on 01 July 2016, 08:46:46 pm

... I have noticed they are 5k resistance not 10k like the standard ones. Will this cause an issue?

No. The internal resistors are only there to damp out high frequency oscillations that cause radio interference and the values are not critical.

Kentish · « **Reply #19 on:** 02 July 2016, 01:30:54 pm »

Quote from: Fazerider on 02 July 2016, 08:58:18 am

Quote from: Kentish on 01 July 2016, 08:46:46 pm
... I have noticed they are 5k resistance not 10k like the standard ones. Will this cause an issue?
No. The internal resistors are only there to damp out high frequency oscillations that cause radio interference and the values are not critical.

lol radio interference...