Hesitation, surging and crap mpg.

[Lawrence]

That's why I bought them, they were recommended on here.  Haynes says the resistance of the caps should be 10Kohm, those are 5.  Swapping them back (and that's the only change that was made) had a huge impact on how it ran.

[darrsi]

That's very interesting!!!
I wonder if that might be a reason why my bike's slightly unhappy around the 3000rpm mark at lower speeds?
I've always blamed the short end can!  :look
Gonna have to see if i've still got the originals to try, 'cos i'm certainly not gonna pay £52 each for new ones?  :eek

[Lawrence]

Sod £200 for a set, that's not far off what my bikes worth  :rollin  I'm sure NGK will have something suitable, just a case of finding the right one.

[Fazerider]

As Darssi says, lots of us are using the NGK plug caps. There is nothing wrong with having a 5k ohm resistor instead of 10k, the thing's only there to stop radio frequency interference and the value is not critical. If those caps really are causing the problem it'll be due to breakdown of the insulation i.e a faulty one... or tracking due to dirt/moisture... or not having a good connection to the plug or ht cable. The value of the suppression resistor being 5k rather than 10 is not the problem.

[darrsi]

I never knew it was all so complex, i just thought caps were caps?

[darrsi]

I would've thought that there'd be loads of people complaining of issues if it was the NGK caps?

[Lawrence]

I'll give them another go then, but that's definitely the only thing that was changed.  All the HT leads were secure in the caps and the I didn't trim them when I put the standard caps back on.

This needs more investigation, I'll check it out more at the weekend

[darrsi]

So, in theory from what you're saying, according to this NGK chart we "should" need SD10F caps, but they don't actually exist so i can't see it being too much of an issue, although it's interesting what the Haynes manual says.
Saying that, electrics and me don't get on too well.  :thumbdown 


http://www.ngksparkplugs.com/docs/resistor_covers.pdf

[Lawrence]

From a quick read, using 5k caps instead of the standard 10k will mean that the coil discharges quicker, giving you a stronger spark that doesn't last as long.  It might be that the shorter spark, coupled with whatever else is wrong with it, is making it run like a bag of shite.  If I can sort out the other thing (carbs possibly) then the 5k caps might work a treat...

http://www.ultralightnews.ca/articles/re...dplugs.htm
http://forums.sohc4.net/index.php?topic=67096.0

[darrsi]

All i got was "Use these as replacements for superior performance on your bike."

That'll do for me :lol

[dBfazer600]

[quote author=Lawrence link=topic=10010.msg103678#msg103678 date=1380045783]
Part way there...

Took the coils off to check resistances, checked first one and it was ok.  Checked the caps (NGK SD05Fs that went on a few weeks back) and they're 5k ohm, which is half what Haynes reckons they should be.  Checked the originals, after digging them out of the bin, and they were all 10 ± 0.4 Kohm.  Stuck them all back on, re-assembled and it's much better than it was.  Still hesitates around 7k but pulled through it and then right up to 12k.  Shall see what the mpg is like tomorrow, hopefully it'll be better as it's costing me an extra £15-£20/week at the moment.

Oddly enough I don't remember it getting worse when I fitted them otherwise they'd have come straight back off  mash 

These are the ones I got and as it turns out they're wrong so don't buy them.

Loads of us have got them, including me?
[/quote]

This includes me and I have been having problems with a stuttering  :faz

I may just get out the old uns and see what happens.

Daz

[darrsi]

[quote author=darrsi link=topic=10010.msg103687#msg103687 date=1380046776]
[quote author=Lawrence link=topic=10010.msg103678#msg103678 date=1380045783]
Part way there...

Took the coils off to check resistances, checked first one and it was ok.  Checked the caps (NGK SD05Fs that went on a few weeks back) and they're 5k ohm, which is half what Haynes reckons they should be.  Checked the originals, after digging them out of the bin, and they were all 10 ± 0.4 Kohm.  Stuck them all back on, re-assembled and it's much better than it was.  Still hesitates around 7k but pulled through it and then right up to 12k.  Shall see what the mpg is like tomorrow, hopefully it'll be better as it's costing me an extra £15-£20/week at the moment.

Oddly enough I don't remember it getting worse when I fitted them otherwise they'd have come straight back off  mash 

These are the ones I got and as it turns out they're wrong so don't buy them.

Loads of us have got them, including me?
[/quote]

This includes me and I have been having problems with a stuttering  :faz

I may just get out the old uns and see what happens.

Daz
[/quote]


Won't hurt to try i s'pose, it's not exactly a major is it? 

[Frosties]

As Darssi says, lots of us are using the NGK plug caps. There is nothing wrong with having a 5k ohm resistor instead of 10k, the thing's only there to stop radio frequency interference and the value is not critical. If those caps really are causing the problem it'll be due to breakdown of the insulation i.e a faulty one... or tracking due to dirt/moisture... or not having a good connection to the plug or ht cable. The value of the suppression resistor being 5k rather than 10 is not the problem.

Well said fella!

[Ebme Geek]

+1

[Lawrence]

It was running far better this morning than yesterday.  Still has the hesitation that it always had, but the really shit running has gone.

When I service it at the weekend I'll stick the NGK caps back on and try it again.

[Lawrence]

Just done a service (oil + filter, air filter, fuel filter, plugs, front sprocket, coolant) and it's running exactly the same as before but now it sounds weird  :rolleyes   Sounds a bit like an Impreza, although it goes just the same as before which is odd.  I'll leave it for a bit as it might've been me spilling something in the electrics...

I cleaned the carbs out too, is there anything I should've done after to prime them?  I just flicked the ignition off/on a few times to run the pump.

[Fazerider]

Just done a service (oil + filter, air filter, fuel filter, plugs, front sprocket, coolant) and it's running exactly the same as before but now it sounds weird  :rolleyes   Sounds a bit like an Impreza, although it goes just the same as before which is odd.  I'll leave it for a bit as it might've been me spilling something in the electrics...

I cleaned the carbs out too, is there anything I should've done after to prime them?  I just flicked the ignition off/on a few times to run the pump.

Running the pump is all it needs, though as you noticed it does cut off if it doesn't detect the pressure rising after clicking for a few seconds.


Are cylinders 3 and 4 still running cooler?

[Lawrence]

Yeah I had to do it a few times until it got to the usual point of slowing right down as the pressure builds up, like it does if you leave it off overnight.

Not sure, I only went for a quick run down the road and back.  Next time I take it out I'll check.

[Lawrence]

Turns out that in first/second gear when I gave it some welly it was ok.  In higher gears it ran like a sack of shite.  Was on the way home and planning on taking the carbs out again to check them out (it wasn't getting (enough) fuel to #4, sparking but header was ~50C when the others were ~150C) and 10 minutes before I got home it suddenly cleared and went back to normal.

So to summarise, it still hesitates like before but at least I haven't made it worse

[darrsi]

Just had a read of this and the fella explains very well how carbs work, it's worth a look. 


http://au.answers.yahoo.com/question/ind...029AAd5QCo