how can is top my sparkplugs arcing?

[aj1soad]

im having a bit of trouble with spark plug number 3. everytime it rains water settles near the spark plug and makes it missfire. ive checked the drain hole and its clear. it rained a bit this morning and my bike was outside and when i start it up you can hear like a poping noise and when i level the bike up you can see water draining out. also when the bike was running i touched the spark plug lead and got a shock :| could i have a problem with the ht lead not getting a complete seal around the plug? i did try putting a bit of copper grease around the base of the rubber to try and stop water getting in but obviously hasnt worked. any ideas? thanx

[darrsi]

Maybe a new set of NGK caps might help, after chopping about 5mm off the ends of the leads before fitting. They're only about £11 a set.


And copper grease won't do anything, WD40 is your friend here (Water Displacement)




http://www.ebay.co.uk/itm/1x-NGK-Resisto...35bb7ed7f4

[alexanderfitu]

Try cutting about 5mm off the end of the ht lead and screwing the cap back on. The end goes brittle with the head and doesnt help water ingress.

[aj1soad]

thanx for the quick replys. how would i go about cutting the cable. does it just screw off or do i need to undo the screw inside the plug cap?

[aj1soad]

ok so i just unscrewed the wire and snipped around 5mm off. i sprayed wd40 on plugs 3 and 4 and where ive got the bike on the side stand obviously the wd40 wont drain away but should i still be hearing that popping noise or is that just a sign that the ht plug is faulty and arcing somewhere?

[darrsi]

Swap number 3 cap with number 1 cap and see if the popping swaps sides?

[Punkstig]

Replace the cap and absolutely smother the cap top and bottom with normal grease to stop water getting anywhere near the leads or plugs.
This issue was my only fault with the fzs600, exposed engine to the elements!

[aj1soad]

so i got my new NGK spark plug caps this morning and ive just fitted them. good thing is i didnt get a shock when i touched the leads but it still makes the funny popping noise when i get water or WD40 on spark plug no 3. the sound is like blowing bubbles in water. when i tilt the bike to the right to drain the wd40 ive sprayed there it still makes the noise slightly. could this be a problem with the spark plug not in the right place? one way i did manage to stop the noise a bit was to pull the rubber boot at the bottom of the spark plug cap down a bit then fit the cap on the spak plug.

[Dead Eye]

Sounds like you have pressure escaping from the cylinder up past the spark plug... does the popping frequency increase when you rev the engine? Never heard of anything like that before though so could very well be wrong

[aj1soad]

its hard to tell really as the exhaust is quite loud. if that was the case what options would i have to fix it?

[aj1soad]

also if that was the case would it cause the bike to misfire and idle funny when water got near the plugs? cos i doubt that water could get into the head while running coz of the pressure?:S

[His Dudeness]

Try wrapping the cap and lead in insulating tape as a quick fix. Also try starting it in the dark and check for arcing

[darrsi]

Have you actually removed the plug?
It's not cross threaded is it, or even just loose?

[Dead Eye]

its hard to tell really as the exhaust is quite loud. if that was the case what options would i have to fix it?

Hard to say without some further testing. Have you tried swapping the spark plugs around? How old are the plugs / when did you replace them?

If it is a leak then it probably means bad threads on either the spark plug (fingers crossed) or in the head. If the former, then a new plug should stop it, if the latter then it means either new head or having it helicoiled. As for the cause - previous owner / mechanic could have tightened the spark plug too much and stripped the threads?

All of this is complete guess work at this stage as its all based on an assumption.

First step, swap the plug with a different cylinder and test - if you can, stick a photo up of the plug #3

[aj1soad]

plugs are new and ive tried swapping them around. one thing that could be causing the problem is a few months ago i had a snapped spark plug in no 3 but i got someone to drill it out and re thread it. while i was hoovering inside holes 3 and 4 now with a small piece 6mm tubeing connected to the hoover on no 3 the pipe would go quite far down, more than the depth of the thread on the spark plug but on no 4 it would only go as far as the depth of the spark plug thread. could the guy i got to fix it have drilled to far?
if i was to replace the head what sort of costs would i be looking at to get a garage to do it? also what other parts/seals would i need? ive seen a head for sale on ebay http://www.ebay.co.uk/itm/321173771905?s...1423.l2649

[lds1973]

plugs are new and ive tried swapping them around. one thing that could be causing the problem is a few months ago i had a snapped spark plug in no 3 but i got someone to drill it out and re thread it. while i was hoovering inside holes 3 and 4 now with a small piece 6mm tubeing connected to the hoover on no 3 the pipe would go quite far down, more than the depth of the thread on the spark plug but on no 4 it would only go as far as the depth of the spark plug thread. could the guy i got to fix it have drilled to far?
if i was to replace the head what sort of costs would i be looking at to get a garage to do it? also what other parts/seals would i need? ive seen a head for sale on ebay http://www.ebay.co.uk/itm/321173771905?s...1423.l2649

I think you need to take the head off and look at the threads on cylinder 3. Its obviously not right. Regarding the tube going down, I should hope it does go down past the threads as that's the way to the cylinder. When you were hovering I guess number 3 cylinders piston was lower down than number 4s.

[aj1soad]

yeh that would probably explain that then

[darrsi]

Would've probably been an idea to mention earlier about the re-thread on number 3 don't you think?  :lol

[Dead Eye]

Yep, definitely sounds like the thread for plug 3 has been re-tapped incorrectly / out of spec

Might be possible to have it redone but I'm not sure if that's a sensible approach? A second hand head is about £50~ as far as I am aware (based on other threads). The work required to replace it is fairly straight forward as it can be done with the engine still in the frame. A little time consuming in that you will need to make sure the engine timing is correct on reassembly but I'd expect a competent mechanic could do it in 2-3 hours? Complete guess though

Could take a bash at it yourself, timing the engine isn't too difficult on the Fazer from what I've heard - I will be doing this when I get round to re-assembling the one I have in the garage