Author Topic: Hesitation, surging and crap mpg. (Read 15366 times)

darrsi · « **Reply #25 on:** 24 September 2013, 07:45:22 pm »

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

Lawrence · « **Reply #26 on:** 24 September 2013, 07:47:11 pm »

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 · « **Reply #27 on:** 24 September 2013, 07:56:55 pm »

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.

Lawrence · « **Reply #28 on:** 24 September 2013, 07:59:40 pm »

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/resistorcapsandplugs.htm
http://forums.sohc4.net/index.php?topic=67096.0

darrsi · « **Reply #29 on:** 24 September 2013, 08:06:59 pm »

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

That'll do for me

dBfazer600 · « **Reply #30 on:** 24 September 2013, 08:08:07 pm »

Quote from: darrsi on 24 September 2013, 07:19:36 pm

Quote from: Lawrence on 24 September 2013, 07:03:03 pm
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

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?

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

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

Daz

darrsi · « **Reply #31 on:** 24 September 2013, 08:17:07 pm »

Quote from: dBfazer600 on 24 September 2013, 08:08:07 pm

Quote from: darrsi on 24 September 2013, 07:19:36 pm
Quote from: Lawrence on 24 September 2013, 07:03:03 pm
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

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?

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

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

Daz

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

Frosties · « **Reply #32 on:** 25 September 2013, 07:46:36 am »

Quote from: Fazerider on 24 September 2013, 07:39:01 pm

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 · « **Reply #33 on:** 25 September 2013, 09:34:01 am »

Lawrence · « **Reply #34 on:** 25 September 2013, 01:02:52 pm »

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 · « **Reply #35 on:** 05 October 2013, 05:40:52 pm »

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

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 · « **Reply #36 on:** 06 October 2013, 12:16:49 am »

Quote from: Lawrence on 05 October 2013, 05:40:52 pm

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 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 · « **Reply #37 on:** 06 October 2013, 12:18:26 am »

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 · « **Reply #38 on:** 11 October 2013, 08:17:24 pm »

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 · « **Reply #39 on:** 12 October 2013, 07:06:40 am »

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/index?qid=20071102043029AAd5QCo

Lawrence · « **Reply #40 on:** 03 December 2013, 03:55:10 pm »

Right, need to get this sorted now. It's got worse recently to the extent that it's hard work getting it past 70, it misfires constantly over 5k and even in neutral at 4k you can hear it's not running right. It's also drinking fuel, and doing 100 miles/day it's getting expensive. It's had new filters, plugs, caps, coils, carbs and still runs like a bag of shit. Tps has been checked and is ok. Battery voltage is steady at over 14v (I'll get an exact reading later).

What else can I try? I've got a gallon of petrol and some matches ready which I could try but hesitant to use those yet...

Ta

Fazerider · « **Reply #41 on:** 03 December 2013, 05:14:48 pm »

You're doing long trips so this is a long shot, but we are in the carb icing season. Worth a check of the carb heating circuit? At least it should be possible to blow through them without taking them off, they're a bugger to refit in cold weather.
Beyond that it is pointing to an ignition problem I guess.
Flooding carbs would make it hard to start, as would low compression. Fuel starvation would explain a lack of power, but that doesn't tally with high consumption and an exhaust full of soot.
Have you gone round all the electrical connections making sure they're clean and tight?
Make a careful inspection of the wiring harness too: check where flexes with the steering and look for places where it can vibrate and chafe against things... particularly near the ignitor box in the tail unit, that was where I had a wire break in the immobiliser wiring.
Failing that, I'd try a swap of ignitor box and, it pains me to say, the regulator/rectifier. (I have no idea how that caused Red98's problem!)

dBfazer600 · « **Reply #42 on:** 03 December 2013, 05:21:16 pm »

Mine had a similar problem and went down the same road as you. In the end I did 3 jobs at once.

Rad flush second time.
K & N air filter to replace stock filter with 100 miles on it.
Carb clean took out all the jets and poked the hell out of em used a guitar string and socked in carb cleaner but took the rubber washers off em.
Make sure you clean and poke the hell out off the rad connection pipes on the carbs as well. As I was sure it was not helping and aided in the icing

Put it all back together and made sure everything was seated and air tight with no cracks in.

It did the job for mine

Daz

darrsi · « **Reply #43 on:** 03 December 2013, 07:25:32 pm »

Quote from: Fazerider on 03 December 2013, 05:14:48 pm

You're doing long trips so this is a long shot, but we are in the carb icing season. Worth a check of the carb heating circuit? At least it should be possible to blow through them without taking them off, they're a bugger to refit in cold weather.
Beyond that it is pointing to an ignition problem I guess.
Flooding carbs would make it hard to start, as would low compression. Fuel starvation would explain a lack of power, but that doesn't tally with high consumption and an exhaust full of soot.
Have you gone round all the electrical connections making sure they're clean and tight?
Make a careful inspection of the wiring harness too: check where flexes with the steering and look for places where it can vibrate and chafe against things... particularly near the ignitor box in the tail unit, that was where I had a wire break in the immobiliser wiring.
Failing that, I'd try a swap of ignitor box and, it pains me to say, the regulator/rectifier. (I have no idea how that caused Red98's problem!)

This problem started when it was in really warm weather so i think carb icing can safely be ruled out.
When i had it the bike virtually came to a stop anyway, whereas his bike is still running, albeit roughly.

He's still describing symptoms of a faulty TPS to me........rough running, bad fuel consumption, misfiring, etc.

Fazerider · « **Reply #44 on:** 03 December 2013, 08:27:12 pm »

Quote from: darrsi on 03 December 2013, 07:25:32 pm

Quote from: Fazerider on 03 December 2013, 05:14:48 pm

You're doing long trips so this is a long shot, but we are in the carb icing season. Worth a check of the carb heating circuit? At least it should be possible to blow through them without taking them off, they're a bugger to refit in cold weather.
Beyond that it is pointing to an ignition problem I guess.
Flooding carbs would make it hard to start, as would low compression. Fuel starvation would explain a lack of power, but that doesn't tally with high consumption and an exhaust full of soot.
Have you gone round all the electrical connections making sure they're clean and tight?
Make a careful inspection of the wiring harness too: check where flexes with the steering and look for places where it can vibrate and chafe against things... particularly near the ignitor box in the tail unit, that was where I had a wire break in the immobiliser wiring.
Failing that, I'd try a swap of ignitor box and, it pains me to say, the regulator/rectifier. (I have no idea how that caused Red98's problem!)

This problem started when it was in really warm weather so i think carb icing can safely be ruled out.
When i had it the bike virtually came to a stop anyway, whereas his bike is still running, albeit roughly.

He's still describing symptoms of a faulty TPS to me........rough running, bad fuel consumption, misfiring, etc.

I did say it was a long shot.
But the OP says it ran OK in lower gears and then started spluttering so it's not impossible that time was the relevant factor rather than the road speed... so there could be icing. He also said it's got worse since the summer... so it could be icing.
Since a test can be done in ten minutes by taking the little pipe off the right hand side of the radiator, blocking the rad outlet with a finger and undoing the filler cap to see if coolant pisses out of the hose or not, is it really an unreasonable thing to check?

darrsi · « **Reply #45 on:** 03 December 2013, 08:41:30 pm »

Stick 200-300ml of 99% Isopropyl Alcohol in a full tank of fuel, it will stop carb icing immediately by binding with any water and burning it as fuel, and it will lower the freezing point, stopping any icing occurring.
If it isn't that then it won't make the bike run any worse at all, the ratio is far too small and it's obviously highly flammable so just ignites as normal, plus it's tried and tested.....by me.

Note: It must be the 99% stuff, if you get the 70% version then you'll also add 30% water as well which will cause you even more problems instead.

elbrownos · « **Reply #46 on:** 03 December 2013, 09:11:38 pm »

Carb icing is nothing to do with water in the fuel. It's humidity in the air that freezes.
The air temperature drops as it expands through a restriction (the throttle butterfly)
Moisture condenses out of the air and freezes in the carb.
Not saying there's any harm in putting isopropyl alcohol in your fuel, but it won't help with carb icing.

darrsi · « **Reply #47 on:** 03 December 2013, 09:38:36 pm »

Quote from: elbrownos on 03 December 2013, 09:11:38 pm

Carb icing is nothing to do with water in the fuel. It's humidity in the air that freezes.
The air temperature drops as it expands through a restriction (the throttle butterfly)
Moisture condenses out of the air and freezes in the carb.
Not saying there's any harm in putting isopropyl alcohol in your fuel, but it won't help with carb icing.

Erm.......yes it does.......100%.

darrsi · « **Reply #48 on:** 03 December 2013, 10:08:55 pm »

The main ingredient in Silkolene Pro FST is Isopropanol, which is basically the same gear as Isopropyl Alcohol and is the suggested additive to fuel for carb icing.
I tried this Silkolene stuff but they suggest a couple of capfuls in your tank, so it basically just doesn't work because the ratio to fuel is simply too small.
Perhaps if you put the 1% ratio (200ml) as i have said then it may help, but at around £15 a litre that's an expensive habit, although it does have the fancy name and packaging, if you like that sort of thing.
5 litres of Isopropyl is now £14.19 delivered so a much better alternative, and easier on the wallet.
Saying all that, i don't believe that Lawrence's bike has carb icing.
From experience when i first got my bike, it would suddenly run like a tractor, or as if it was running out of fuel (which it was in theory) and the odd thing was that it was exactly one mile away from my house at the same spot where it happened, 3 days in a row
I managed to keep it just about ticking over by keeping the revs high, but it was basically running like shite.
Luckily i phoned my mechanic and he knew the symptoms straight away and told me it would pass once the engine warmed up properly and heated the carbs, which it did after about 10 minutes ticking over at the roadside.
That's when i did some research, tried the Silkolene which helped a little bit but wasn't great, then bought the Isopropyl and that did work a treat, to the point where there were zero signs of icing ever again.
I have been putting it in my tank every winter, at 200ml per full tank (1% ratio) and never ever had it again since then.

So yes, my bike has a booze problem, but it keeps it running sweet so everybody's happy.

Lawrence · « **Reply #49 on:** 03 December 2013, 10:41:33 pm »

TPS has been replaced (with the carbs) but I can always swap back to make sure.

From what I understand about carb icing it's mainly when the engine is cold and in cold weather. When I'm leaving in the mornings now it's ~8C outside, my garage is around 15C and it does it constantly through my 1 1/4 hr commute. Also I'm pretty sure the carb heating pipes are ok as one of the rubber joiners split recently on the way to work (thankfully about 3 minutes before I got there) and was leaking coolant.

Just checked the battery voltages, engine off it was 12.18, warm idling it was 14.03 and at 2500rpm (I don't want to piss my landlord of too much...) it increased a fraction to 14.06. Are these ok?

As for electrical connectors, I'll see if I can take a look at lunchtime tomorrow.