Date: 18-11-18  Time: 18:48 PM

Author Topic: stuttering fzs 600  (Read 189830 times)

red98

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stuttering fzs 600
« on: 11 March 2012, 02:46:51 PM »
my trusty 98 600 fazer has developed a stutter at 7/8000 rpm,i changed the inlet rubbers thinking that this was the problem as they have been split for a few years,but the stutter is still there,its a big one but a bit more gas and it pulls through,i put me carb vacuum guages on this morning and all was well,bike is well looked after and had a good service at the end of last year although the shims have never been looked at,there is a slight tap when cold but soon goes,ive owned the bike for nearly 10 years and never had a problem but with the better weather with us iam keen to sort it out.....iam going to do a compression test this afternoon but iam not expecting anything amiss,just something to cross of the list....new plugs were fitted last service but the caps are origanal so will probably treat it to a new set.....in the back of my mind iam thinking coil packs........any one else had simulaar problems ?
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red98

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Re: stuttering fzs 600
« Reply #1 on: 13 March 2012, 06:50:54 AM »
hi all....well i did the compression test on the fazer last night and was supprised at the results.....all cylinders were down on compression,so looks like rings or valve clearences,i didnt have time to squrt some engine oil in the bores and test again,this would have sealed any worn rings and given me an improved reading on the test,iam sure its the valve clearence as to my knowledge they have never been done,when i got the bike the bike it had 9000 miles now nearly 40000,shims should have been checked at 28000  :eek ....looks like a job for saturday morning.........
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Fazerider

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Re: stuttering fzs 600
« Reply #2 on: 13 March 2012, 10:37:58 AM »
I've found valve clearances on the FZS600 to be amazingly stable. Check them by all means, but don't be surprised if they're in spec... mine still were at three times that mileage.
Nor would I expect low compression to result in those symptoms: reduced power especially at lower revs, difficulty in starting, backfiring (or even backfiring through the carb in the case of inlet valve leakage) would be more likely. If your tester has a valveless adaptor to get it to suit the small plug holes on bike engines then it will give a low reading... they're more useful for picking up on differences rather than absolute measurements.

A new set of plug caps may help, some NGK ones cleared an intermittent misfire for me, but it sounds more like the problem may be the carb slides no longer moving smoothly due to wear. My current set are giving similar results: a massive flat spot with plenty of power available again once you've coaxed it through. It's easiest to provoke by snapping the throttle fully open from cruising at 70-80mph, the sudden difference in pressure jams the slide against the grooves in the carb body and the diaphragm doesn't develop enough force to overcome the friction. Dri-Slide or even applying an 8B pencil to the grooves will relieve the problem for a while, long enough to prove the theory anyway.

red98

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Re: stuttering fzs 600
« Reply #3 on: 14 March 2012, 06:49:41 AM »
thank you...thats given me something to think about...my compression tester is not the best in the world but its also not the worst.and i do as you say use it to compare cylinder pressure,and not rely on the reading to be 100% accurate,thats why i didnt put the results on here....looking at the reaults again there between 30-40% down...the bike performs too well for this to be correct.
 iam going to have a look at the cleanerces this weekend and also replace the plug caps,ive not heard of dri-slide before is that some sort of carb lube ?
 not sure on the valve on the adaptor but will look tonight.......thanks for your help
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Fazerider

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Re: stuttering fzs 600
« Reply #4 on: 14 March 2012, 09:40:25 AM »
...ive not heard of dri-slide before is that some sort of carb lube ?

Just had a look for stockists and found there don't seem to be any in the UK anymore. I used to use it as a lubricant in airgun barrels many years ago. It's molybdenum disulphide suspended in a solvent and came in a can with a needle dispenser. RS do something similar:
http://uk.rs-online.com/web/p/products/0558035/
... but it's in a spray can which will make it awkward to apply precisely. It's probably better to try a very soft pencil, graphite is as good a lubricant and the solvents in the spray might not be too good for the rubber components.

clayt74

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Re: stuttering fzs 600
« Reply #5 on: 16 March 2012, 08:56:52 AM »
Hi,
my fazer 02 has just developed what sounds to be a very similar problem.
it starts fine and runs fine around town as long as im very gentle and smooth on the throttle.
as soon as i try to give it some beans it stutters/judders around 6k rpm (it almost feels like your trying to accelerate in 3 gears too high) the bike does pull through it and then feels fine but have lost confidence in overtaking.
The thing for me is this problem started just after i had given the bike a real good hosing down, so I am assuming that my prob is almost certainly the caps ( I have just pulled them all off and sprayed with WD40 but wont get to ride until after work to see if it fixes the problem)
I would definately start with caps before taking the carbs apart.

Gnasher

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Re: stuttering fzs 600
« Reply #6 on: 16 March 2012, 12:49:57 PM »
I've found valve clearances on the FZS600 to be amazingly stable. Check them by all means, but don't be surprised if they're in spec... mine still were at three times that mileage.
Nor would I expect low compression to result in those symptoms:

 :agree
 
  This is either electrical or fuelling, start with the easy things i.e. plugs as already mentioned.  Wait until it's dark or turn out the light in your garage lift the tank and start the bike now look for aching around the top end you may have to move around to see it and check inside the plug wells but it will be obvious. It's a common problem on high mileage bikes replace the cap/lead/plug if they are arching it may be worth changing the plugs as a matter of course and make sure the gap is correct.
 
If the above is all ok and changing the plugs does nothing start looking at the fuelling begin with obstructions in the air intake, then the filter either clean it or replace it.  Then move to the carbs looking for blocked main jet/s and emulsion tube/s and holed diaphragm/s these can be tiny and will get you the very symptoms you've got.
     
Later

red98

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Re: stuttering fzs 600
« Reply #7 on: 17 March 2012, 01:12:28 PM »
thanks for the replys...looks like were all thinking the same way....ive checked the clearences this morning and as mentioned by fazerider there not too far out,not been done before and bike now on 40,000 miles,results below
 
                 inlet                                      exhaust
              0.11-0.20                                0.21-0.30
 
1               0.12                                         0.20
                 0.15                                         0.20
 
2               0.11                                         0.20
                 0.11                                         0.19
 
3               0.11                                         0.19
                 0.11                                         0.19
 
4               0.12                                          0.18
                 0.13                                          0.18
 
i could go up a size (0.05)which would put me in the middle of recomended clearences (haynes manual) or go up two sizes which would put me at the top end......or the third option leave as is ......iam just on my way to local yam dealer to see what they think and also to pick up some new plug caps.....will post there answer later :rolleyes                       
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red98

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Re: stuttering fzs 600
« Reply #8 on: 17 March 2012, 04:01:20 PM »
just got back from yam dealer,got four ngk caps and 2 meters of ht lead for £20.01,£2.50 per metre for the lead,3.75 each for the caps.enquired about the price of shims and was supprised :eek  at between £4/£5 each,if you needed to replace the whole lot that would be close to £80,can you get pattern parts?
 had a word with the mechanic while i was down there,he said not to worry about the inlet clearences but it might be worth doing the exhaust,but if it was his bike he wouldnt bother.
 i asked about the stuttering and he said exactly as  mentioned on here by FAZERIDER and GNASHER ,my thanks to you both  :D ......CARBS....in particular emulsion tube,main jets and diaphram,either blocked or split...could also be moisture in the float bowls,which could be your problem CLAYT74  ;) .
  iam going to look for pattern shims and just do the exhaust valves,and then remove the carbs and give them a good clean and check over
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red98

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Re: stuttering fzs 600
« Reply #9 on: 17 March 2012, 04:14:04 PM »
wemoto can do shims at £3.58.....thats better....inless of course you know different ;)
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red98

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Re: stuttering fzs 600
« Reply #10 on: 18 March 2012, 07:46:06 AM »
ah................ :o :o     had a quick look at the ht leads last night,looks like they are sealed at the coil end which means if the leads are faulty ill have to replace the coils :( ....iam going to replace the caps this morning and also remove the carbs and clean/inspect....will up-date later
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wannafazer

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Re: stuttering fzs 600
« Reply #11 on: 18 March 2012, 06:51:02 PM »
Interesting. I was going to change my plug caps (for the second time) and was going to do the HT leads cos it's a cheap as chips and they are 12 years old. Didn't realise they were sealed at the coil end. Assumed they'd just screw off.
The only real Fazer is a carbed 600.

red98

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Re: stuttering fzs 600
« Reply #12 on: 18 March 2012, 07:01:31 PM »
carbs off today and given a good clean on the outside before i stripped them down,i did notice before i took them off that the throttle was`nt snapping shut like it use to,the return springs were well gummed up,difficult to see when on the bike,soon cleaned off with an air line,wd4o and an oily rag,came up realy well,took the tops off and all the diaphrams look good needles as well,then took the bowls off and removed the floats,only slight gunge in the bowls now all clean,then removed the jets,main jets were fine no problems,2 of the pilot jets were blocked,not completly but enough to restrict flow,a quick soaking and a blast with the air line soon cleared them,throttle snaps back now until i put the cables back on  :(  took them both off and gave them a blast of wd and worked them in and out a few times and refitted,problem sorted,took a while to start until the fuel reached the engine and then fired up well,think its running a bit smoother now and deffinatly picks up better on the throttle.........ive got to put all the bits and peices back on yet so could`nt go for a test ride....might do this one night in the week
  went to fit the new caps only to find they are the wrong ones (yam dealer)not long enough and the wrong angle, going to take them back tommrow  :\
 will update when its all back together and ive been on a test ride ;)
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red98

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Re: stuttering fzs 600
« Reply #13 on: 18 March 2012, 07:05:54 PM »
Interesting. I was going to change my plug caps (for the second time) and was going to do the HT leads cos it's a cheap as chips and they are 12 years old. Didn't realise they were sealed at the coil end. Assumed they'd just screw off.

thats what i thought....i bought the lead at yam dealer.i told them what bike it was too :\  not sure how long they last but mine are hard at the ends
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wannafazer

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Re: stuttering fzs 600
« Reply #14 on: 18 March 2012, 07:42:44 PM »
red, are you absolutely sure they're sealed cos' you said "looks like" ?  It's too dark for me to have a squint now.
The only real Fazer is a carbed 600.

red98

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Re: stuttering fzs 600
« Reply #15 on: 18 March 2012, 08:09:36 PM »
i must admit i didnt look today,just last night in the dark,i will check tommrow when i get in,the bikes still in bits so easy to see
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wannafazer

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Re: stuttering fzs 600
« Reply #16 on: 18 March 2012, 08:13:56 PM »
I'd appreciate that, chances are it'll be dark when I get home from work.


Les
The only real Fazer is a carbed 600.

red98

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Re: stuttering fzs 600
« Reply #17 on: 19 March 2012, 07:09:08 PM »
took the plug caps back to yamaha dealer today,got a refund no problem,according to them ngk dont list a cap for the fazer  :(  genuine yamaha caps.....wait for it....................................£53 each  :eek :eek :eek ....i came home empty handed..anyone know where i can get some caps from at a reasonable price ?
 
WANNAFAZER.......had a look at the coils when i got home,the leads are sealed to the coils so if the leads are faulty you have to replace the coil as well  :\
 
no work on the fazer tonight,might do a bit tommrow.......
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wannafazer

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Re: stuttering fzs 600
« Reply #18 on: 19 March 2012, 07:37:30 PM »
Thanks Red, forget the Yam plug caps NKG SD05F are the ones you need. They're straight not angled but fit absolutely fine.
The only real Fazer is a carbed 600.

red98

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Re: stuttering fzs 600
« Reply #19 on: 19 March 2012, 07:44:38 PM »
hi wannafazer.....i was thinking a straight one would work :) ........thanks for the part number,will look on ebay
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red98

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Re: stuttering fzs 600
« Reply #20 on: 19 March 2012, 08:04:15 PM »
just bought 4 plug caps on ebay for £8.80 + free delivery..........bargain  :)
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wannafazer

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Re: stuttering fzs 600
« Reply #21 on: 19 March 2012, 08:08:23 PM »
 :lol
The only real Fazer is a carbed 600.

wannafazer

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Re: stuttering fzs 600
« Reply #22 on: 19 March 2012, 08:34:13 PM »
By the way, chuck your old ones in the bottom of your toolbox. They won't all be fucked and will get you out of a hole one day, like mine did last Saturday.
The only real Fazer is a carbed 600.

happy biker

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Re: stuttering fzs 600
« Reply #23 on: 19 March 2012, 08:47:20 PM »
make you right the best one are the carb ones :rollin

clayt74

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Re: stuttering fzs 600
« Reply #24 on: 20 March 2012, 08:21:47 AM »
I think i got lucky with mine, it seems the only issue i had was a bit of water ingress into 1 of the caps. a good douse of WD40 and the symptoms were immediately gone, no matter how hard i pushed it to wot.
over the weekend i had the tank off to replace airfilter and whilst there cleaned and checked all leads and caps thoroughly as well as cleaning the seating area all around the plugs could see no proplems, I waited till dark and checked for any arcing or tracking as suggested, but could find nothing and the bike was still running a treat.
the only additional thing i did was to put some almagamating tape around where the HT leads enter the cap just as a precaution cos i ride all year round and believe prevention is better than cure.
hope yours is running sweet soon