Spluttering at low revs

[sc0ttie]

I have a 1999 FZS600 I have owned it for 18 months and it is now on 70,000 miles. Recently it has developed a spluttering power delivery in low revs, typically below 2000rpm and usually when cold but it has happened a few times now when the engine is fully warmed up, which has prompted me to post here.


Since ownership i have always used standard 95 unleaded fuel. never had a problem. The bike starts usually first time, amazingly and tick over is fine, no problems with that. It is just really when pulling away, in first and in low revs in second gear in traffic, it seems very boggy and splutters until it gets up to 3000rpm. Not every time, but its happening more often now.


Where do i start to check for solutions to this issue? electrical or fuel related?

[darrsi]

Ever had the carbs balanced?
Unbalanced carbs will be most noticeable under 2500rpm or at low speeds, resulting in the need for more throttle and clutch control.
Check the TPS is positioned correctly as well, if that's out that can cause low rev jerkiness.

[sc0ttie]

I haven't had them balanced since I have owned it. I will check the TPS and see what comes up on the rev counter. I don't own a carbtune either.

[darrsi]

Probably just needs a good balancing, but before doing so make sure your air filter is in good nick and breathing okay, if you're not sure i'd get it changed.
In fact, saying that, is your air filter okay? When was it last changed?

[sc0ttie]

I haven't changed it so this is another thing I will check this weekend, will check the TPS first then the air filter.

[darrsi]

If you have no real history of servicing then i'd change the air filter anyway.
Don't buy the cheapest one you can find because it's false economy.
If you don't mind parting with 40 quid then i would always recommend a K&N, but that's obviously your choice, but it'll be the last one you need to buy for the bike as they are washable.

[His Dudeness]

could be spark plug caps. ngks 

[YamFazFan]

Ever had the carbs balanced?
Unbalanced carbs will be most noticeable under 2500rpm or at low speeds, resulting in the need for more throttle and clutch control.
Check the TPS is positioned correctly as well, if that's out that can cause low rev jerkiness.

How often would you expect to have to carry out carb balancing on Fazer 600's?.

Also, would you expect to completely eliminate any clutch rattle at idle (without the clutch lever pulled in) with perfect balancing?.

Ta.

[darrsi]

Ever had the carbs balanced?
Unbalanced carbs will be most noticeable under 2500rpm or at low speeds, resulting in the need for more throttle and clutch control.
Check the TPS is positioned correctly as well, if that's out that can cause low rev jerkiness.

How often would you expect to have to carry out carb balancing on Fazer 600's?.

Also, would you expect to completely eliminate any clutch rattle at idle (without the clutch lever pulled in) with perfect balancing?.

Ta.

I tend to do my carbs during summer time, or whenever i feel it needs it basically.
It's good practice to make sure the air filter is in good nick beforehand though in my opinion for best results.
Balancing will help with clutch rattle, as will the correct RPM setting at tickover, i've been surprised how low revs some people have had their bike set at on recent posts on here.
1250rpm has always been around right for my bike once warm.

[stevierst]

I've just balanced my carbs and reset my TPS after the same symptoms as you've said you had sc0ttie. Mine sounded like a Subaru Impreza at low revs, very annoying!

I changed the plugs, caps, and balanced the carbs. Made no difference. Mine turned out to be the TPS which was miles out! Took her for a short blast after doing all that, and the stuttering has now gone.
Never had to adjust a TPS before in the 4 fazers and 100k+ miles I've done on them!!!

Every days a school day!!

[sc0ttie]

My problem turned out to be worn plugs, the electrode on them was receding, they looked to be a couple of years old so I replaced them with NGK plugs and now the bike runs fine. The TPS was fine and the air filter was like new still.

[darrsi]

My problem turned out to be worn plugs, the electrode on them was receding, they looked to be a couple of years old so I replaced them with NGK plugs and now the bike runs fine. The TPS was fine and the air filter was like new still.

That's why i spend a couple of quid more per plug and buy Iridium ones, it makes economic sense.


http://www.ngk.com.au/spark-plugs/product-information/spark-plug-types

[darrsi]

I've just balanced my carbs and reset my TPS after the same symptoms as you've said you had sc0ttie. Mine sounded like a Subaru Impreza at low revs, very annoying!

I changed the plugs, caps, and balanced the carbs. Made no difference. Mine turned out to be the TPS which was miles out! Took her for a short blast after doing all that, and the stuttering has now gone.
Never had to adjust a TPS before in the 4 fazers and 100k+ miles I've done on them!!!

Every days a school day!!

I know the exact noises and feeling my bike makes when the TPS is wrong now, it will be worth you checking it more often as if it was that ropey it could be a sign that it's slowly breaking down.
They don't tend to just stop working, they misbehave, the bike will feel a bit jerky and either the RPM needle will move about much more often or it will remain fixed on 0rpm or 10,000rpm.
If you ever think it's finally pegged out, just buy a new one, don't buy a 13+ year old used one as it'll just happen again eventually.


http://www.ebay.co.uk/itm/Drosselklappensensor-TPS-101-Yamaha-FZS-600-DROSSELKLAPPE-13550-13D60-4HD-85885-/361403667980?hash=item542556560c:g:svIAAOSw2s1UxgsX
 

[stevierst]

Cheers darrsi, I'll bear it in mind if it starts playing up again!


Sent from my iPad using Tapatalk