98 Fzs6 reverting from 2/3 cyclinders to 4 constantly.

[KyleBeeson]

Hello basically I have a 98 fazer with 35k on the clock, I brought the bike about 6 weeks ago, its very hard to explain the problem I'm having.. basically I first noticed that my bike would lose throttle response and judder, basically would pull the throttle back 1/4 way and nothing would happen then a few seconds later it would kick in but eventually the engine would be running down the revs, pulling back the throttle would do nothing, pulling in the clutch would cut the engine.. while stopped, sometimes it'd start back up straight away other times you had to wait 1-15 minutes, always basically starting on 2-3 cylinders, would have to manually pull the throttle back to keep the engine alive, eventually it would revert to all four, I've put in 50:1 fst fuel additive , which on the bottle says its the most i should put it (360ml, 18 litre tank) but it hasnt helped at all really, I've been told carb freeze by someone, but i cant see how mine suffers from it so bad, and two friends of mine has a foxeye 02 fazer, and the other has a 98-99 one, its been like this for the duration and it being my first big boy bike has left me frustrated not being able to feel comfortable riding it knowing if i give some beans i could face 15 minutes sat trying to start it, the only difference is on my bike I have a aftermarket can, and they are both using stock cans, any help would be amazing, thanks

[darrsi]

FST is crap, especially at the amounts they tell you to use, i've tried it and it's quite useless.
Some bikes suffer from it, others don't, it's the luck of the draw i think.
IF it is carb icing then i would imagine the pipes around your carb heater circuit are blocked, which are part of the coolant system to raise the temperature of the carbs to prevent icing, so ideally they need unblocking so the fluid can flow properly.


Be worth reading this as well:   http://foc-u.co.uk/index.php/topic,5122.msg44462.html#msg44462

[bandit]

Have you tried a new set of sparkplugs, using a aftermarket can shouldn't affect carb balance, only when downpipes are aftermarket it's normally req'd. 

[Dave48]

Don't think it will be anything too serious. As already said check carburettor heater hoses(small bore-easily blocked) and check spark plugs/HT caps & coil connections. If you are systematic and work through the fuel system/ignition system you will find the problem-happens to us all from time to time. Good Luck

[greenman]

I've had similar issues, no. 3 pot wasn't firing well and its downpipe was always cooler.
It missfired and ran like a pig until it decided it would play ball for a while. It turned out to be plug caps, new NGK SDO5F and trimming 1/2 inch off the ends of the HT leads did the trick.

[AdieR]

I don't think it's carb icing.

As the bike is new to you, I'd start by giving it a good service (spark plugs, fuel and air filters, and maybe try fresh fuel without the FST). Is it a dealer buy or private? Service record? At 35k, valve clearances should have been checked by now (is it indicated on paperwork?).

Is it hesitant at all rpm's, or a certain range?

[darrsi]

I'm wondering if you may have water sitting in the carbs, that would give off the symptoms you're saying?
Maybe worth draining the carbs just to cross it off the list.


Have a good read of this and it explains what to do, it's a quick and easy job, but use a decent fitting screwdriver so you don't mess the screws up, don't over tighten them back up, and keep some water or a hose nearby to wash any spilt fuel away.
I'd do it while the engine is cold as well.


  http://foc-u.co.uk/index.php/topic,6574.msg62449.html#msg62449

[KyleBeeson]

Full service history up to 32k and the bloke 'serviced it' before selling it, I've had no time to look at anything on it, I've got a Haynes manual for it but if I'm honest my knowledge about mechanics is minimal haha. I changed spark plugs, going to give it a full service, not sure about how I go about valve clearances etc

[KyleBeeson]

So unsure on what it is, could be anything.. Def strange, ran it in daylight the other day and it was being a dog st 30 round a town, but tonight just been 25 miles, m4 etc and its not missed a beat..

[darrsi]

Did you drain the carbs?

[KyleBeeson]

Yeah I'm about to in about 20 mins lol, would it be best to replace ht leads as well as the caps, or ?

[110%]

Greenman is right, I had the exact same problem. Buy yourself 4 new NGK plug caps and simply trim the existing HT leads to give the caps a fresh bit of metal to contact to.

I wouldn't bother changing the HT leads, they are an absolute nightmare to get out of the coils or to fit some fresh ones without breaking the very brittle plastic clips.

[KyleBeeson]

Yep I tried changing leads and snapped the clips on one, but I think I've located problem but very hard to explain, fuel pump clicks when you turn ignition in the morning 1-5 times, but if you turn your ignition off and on again it won't click, when it dies everytime I turn it on it clicks 5 times, I turns my ignition on and off when it died earlier 25 times and boom when I started it, perfect!!

[darrsi]

Yep I tried changing leads and snapped the clips on one, but I think I've located problem but very hard to explain, fuel pump clicks when you turn ignition in the morning 1-5 times, but if you turn your ignition off and on again it won't click, when it dies everytime I turn it on it clicks 5 times, I turns my ignition on and off when it died earlier 25 times and boom when I started it, perfect!!

The clicking is the pump feeding fuel to the carbs that slightly drains when left standing for a few hours or overnight. The longer the bike is left the more fuel will be needed before start up, so you'll hear more clicking.
If you drained the bowls it probably sounded like a rattle snake when turning the ignition back on 'cos they were empty!
It won't click again straight away because the carb bowls are already full of petrol.

[KyleBeeson]

Yep I tried changing leads and snapped the clips on one, but I think I've located problem but very hard to explain, fuel pump clicks when you turn ignition in the morning 1-5 times, but if you turn your ignition off and on again it won't click, when it dies everytime I turn it on it clicks 5 times, I turns my ignition on and off when it died earlier 25 times and boom when I started it, perfect!!

The clicking is the pump feeding fuel to the carbs that slightly drains when left standing for a few hours or overnight. The longer the bike is left the more fuel will be needed before start up, so you'll hear more clicking.
If you drained the bowls it probably sounded like a rattle snake when turning the ignition back on 'cos they were empty!
It won't click again straight away because the carb bowls are already full of petrol.

Yeah so what would it be then? When it dies I can make the fuel pump click 100 times lol, but when it's running fine and I just turn it on normally clicks once but, I breakdown and it will continuously click and I did it about 50 times earlier and it fired all 4 up straight away

[darrsi]

It still sounds like fuel starvation, like not enough is getting through which is why the pump is doing overtime.
If you've checked for kinked pipes, and the fuel switch under the tank is fully on, then i would definitely change the fuel filter. It may have crap in it from the tank that might be moving about and causing an intermittent blockage.

[Dead Eye]

Agreed, if the fuel pump is going mad after its died then its likely that the float bowls are empty which means fuel isn't getting to the carbs fast enough. Check the routing of all the fuel pipes and replace the filter

[riz]

FST is crap, especially at the amounts they tell you to use, i've tried it and it's quite useless.
Some bikes suffer from it, others don't, it's the luck of the draw i think.
IF it is carb icing then i would imagine the pipes around your carb heater circuit are blocked, which are part of the coolant system to raise the temperature of the carbs to prevent icing, so ideally they need unblocking so the fluid can flow properly.


Be worth reading this as well:   http://foc-u.co.uk/index.php/topic,5122.msg44462.html#msg44462

 
I had a thundercat that struggled with carb icing a lot, the carb heater pipes were clear and the thermostat worked fine, but the engine just ran too cold in the winter, i used to tape a good 1/2 of the rad up for winter which helped to a point but for the colder times i used pro FST and it stopped the icing perfectly, (although i have to admit i switched to the cheaper option of the same % of isopropyl alcohol, and a small splash of redex instead of pro FST, for the next winter).
Again with 'cats some struggled, some didnt, so i guess some will find FST helps and some won't, but i do know it 100% 'cured' my icing on the 'cat.

[Dead Eye]

Makes sense since darrsi's machine seems to start consistently and very smoothly all the time (based on previous topics) and he doesn't have to use the choke - whereas for me, I need to have the choke on for at least a few minutes and even then the bike isn't properly happy until its a few miles in to the journey

[KyleBeeson]

I rid it round nicely in 12 degrees, and its still done it, I've just got a big feeling its not carb icing, taking it done garage Monday for them to be taken apart properly

[riz]

The icing used to happen to me after 10-15 miles of a mixture to speed's, but i noticed it in the slower speed areas, and then above 7-8k rpm it seemed to clear (or was that 4-5k?, cant remember), it also happened once on the m4 comming back from the ace later at night after 30 mins or so of pretty constant throttle. Icing isnt just about temp. its also about moisture in the air.
If you hadn't mentioned the fuel pump relay i would have suggested coil's.
When it happens if you give it WOT does it clear at any point?

[KyleBeeson]

Kind of, but its unreliable there most of the time are no beans to give it

[darrsi]

It's extremely unlikely to be carb icing, it's too warm now.

[richfzs]

carb icing? as others have said, no chance.

check the routing of the breather pipes, its easy to kink them on the early bikes, creates a low pressure in the tank, and try as it will, the pump cant get the fuel down to the carbs....

[KyleBeeson]

I doubt the fuel lines have been changed, so a 15 year old bike I'm sure the lines would need changing soon or more importantly now