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Thread: Spark plug cap replacement

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    Should Get Out More Pax's Avatar
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    Default Spark plug cap replacement


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    Quickie - do I need to cut back the HT lead at all before screwing the cap onto the end of the HT lead? ZZR600

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    At Work iansoady's Avatar
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    Default Re: Spark plug cap replacement

    I always chop 1/4" or so off to make sure I get a good purchase on the core (copper core of course).

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    Default Re: Spark plug cap replacement

    Idiot here didn't take a photo when I took the caps off weeks ago. I believe it's firing 1243, HT leads are labelled 1 & 4 on left coil, 2 & 3 on right.

    So that means 1 goes to far left, 2 crosses to 2nd cylinder from left, 4 crosses to third cylinder from left and 3 goes on fourth cylinder from left.

    I ballsed this up before years ago on a Bandit so I know what can happen (ran, but super rough), but I don't want to get it wrong as I don't want to run it without the airbox on, which is a PITA to put back on and will need removing again if I fook it up. Plus the bike hasn't run for ages so I won't know if it's just taking its time getting going, as well as having minor running issues anyway.

    Who the fuck dreamt this system up ?

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    Should Get Out More Tomcat's Avatar
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    Default Re: Spark plug cap replacement

    Quote Originally Posted by iansoady View Post
    I always chop 1/4" or so off to make sure I get a good purchase on the core (copper core of course).
    Me too, since the screw thread inside the plug cap can chew up the (usually copper wire) core of the HT lead. That said it's been many years since I needed to change one, very reliable things IME.

    Firing order for a conventional IL4 is 1342. For a transverse engine I would expect the left-hand cylinder (viewed sitting on the bike) to be No. 1. However many systems these days are wasted spark, meaning the plug sparks at the top of both compression and exhaust strokes, so in theory you could have more than one combination of leads that would work. 1 and 4 fire together, and 2 and 3 together.

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    Default Re: Spark plug cap replacement

    Yes i always snip also. If you look into your HT Lead you will now see a wee hole the cap screw left. Best getting a new snug fit. BTW if they are numbered 1 to 4 how can you fuck that up? Even Val could work that out

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    Default Re: Spark plug cap replacement

    Leads from one coil go to 1 and 4, leads from the other coil go to 2 and 3, doesn't matter which lead goes to which cylinder, but does matter which coil goes to which cylinder iYSWIM.

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    Default Re: Spark plug cap replacement

    Quote Originally Posted by 1888 View Post
    Yes i always snip also. If you look into your HT Lead you will now see a wee hole the cap screw left. Best getting a new snug fit. BTW if they are numbered 1 to 4 how can you fuck that up? Even Val could work that out
    Because if the firing order isn't 1234 from left to right, then it makes it ambiguous whether you should just go left to right with the numbered cables, doesn't it? Hence me asking the question. Anyway, I found a copy of the Haynes to download and it looks like, only from the photo mind, as they didn't feel it was important to spell this out clearly (as opposed to clearly telling you which screw to undo ), yes, the leads will go 1234, as coils will go as Julian says. I will verify this by looking at the feeds to the coils, because I did write on the coils themselves what colour feeds went to which coil connector, managed to think of that.

    All I need now is a day that hasn't forecast rain, every day that I planned to do it has had intermittent rain, so I've kept putting it off.

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    Default Re: Spark plug cap replacement

    Quote Originally Posted by Pax View Post
    Because if the firing order isn't 1234 from left to right, then it makes it ambiguous whether you should just go left to right with the numbered cables, doesn't it? Hence me asking the question. Anyway, I found a copy of the Haynes to download and it looks like, only from the photo mind, as they didn't feel it was important to spell this out clearly (as opposed to clearly telling you which screw to undo ), yes, the leads will go 1234, as coils will go as Julian says. I will verify this by looking at the feeds to the coils, because I did write on the coils themselves what colour feeds went to which coil connector, managed to think of that.

    All I need now is a day that hasn't forecast rain, every day that I planned to do it has had intermittent rain, so I've kept putting it off.
    1234 isn't the firing order. It's the number cylinder counting left to right as you sit in the bike.

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    Default Re: Spark plug cap replacement

    Quote Originally Posted by Pax View Post
    Because if the firing order isn't 1234 from left to right, then it makes it ambiguous whether you should just go left to right with the numbered cables, doesn't it? Hence me asking the question. Anyway, I found a copy of the Haynes to download and it looks like, only from the photo mind, as they didn't feel it was important to spell this out clearly (as opposed to clearly telling you which screw to undo ), yes, the leads will go 1234, as coils will go as Julian says. I will verify this by looking at the feeds to the coils, because I did write on the coils themselves what colour feeds went to which coil connector, managed to think of that.

    All I need now is a day that hasn't forecast rain, every day that I planned to do it has had intermittent rain, so I've kept putting it off.
    Sitting on the bike left hand coil, Short lead pot number one. One being LHS. Long lead pot number 4. Right hand coil. Longer lead pot 2 and you cant go wrong with the last lead.

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    Default Re: Spark plug cap replacement

    Quote Originally Posted by Tomcat View Post
    Me too, since the screw thread inside the plug cap can chew up the (usually copper wire) core of the HT lead. That said it's been many years since I needed to change one, very reliable things IME.

    Firing order for a conventional IL4 is 1342. For a transverse engine I would expect the left-hand cylinder (viewed sitting on the bike) to be No. 1. However many systems these days are wasted spark, meaning the plug sparks at the top of both compression and exhaust strokes, so in theory you could have more than one combination of leads that would work. 1 and 4 fire together, and 2 and 3 together.
    correct!

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    Default Re: Spark plug cap replacement

    Just getting round to finishing this off. Aaaaaaand with the replacement caps, which are different shape, lead number four won't reach. So next question is - if I go get a new bit of HT lead, do I have to worry about anything, like I should replace all the leads because the new one may have I dunno, different resistance or something? That sort of thing.

    I could just take one of the old caps that is in good looking shape and use that...

    Also, I fired it up anyway. Seems to be running fine - with one exception. It doesn't seem to like hardly any choke now, whereas before it was sort of average (though it would start stuttering after a very short period of time after setting off). I guess it's possible I've just disturbed the cable tension somehow, but it seems all right from what little of it I can see without pulling a load of it off again.

    EDIT: answered already about the HT leads, not to worry.
    Last edited by Pax; 12-09-18 at 15:31.

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    Default Re: Spark plug cap replacement

    Could just be it doesn't need the crutch that is choke because it's just running strong enough to start without it?

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    Default Re: Spark plug cap replacement

    Quote Originally Posted by a_morti View Post
    Could just be it doesn't need the crutch that is choke because it's just running strong enough to start without it?
    If the cap change did that, I'll be over the moon . Either way, the airbox isn't fitted back on properly, the HT cables probably aren't routed properly regards the throttle and clutch cable, coils not screwed onto brackets, tank just sitting on top of it all, just thrown together enough to see that it starts. I'll see what it's like after I've put it all back together again nicely. Number 4 HT cable isn't now long enough to get the coil onto its mount, by about 1cm grr.

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    Default Re: Spark plug cap replacement

    correct

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