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+--- Thread: Rough running 2.5k to 3.5k (/showthread.php?tid=83852)
Rough running 2.5k to 3.5k - Hubb96 - 19-09-25
Hi all,
New to the forum and not long had my 2004 Fazer 1000 but in need of some advice!
To give some perspective the bike runs fine high revs and the way through with smooth throttle, however it has a bit of a lumpy idle and a misfire at 2.5k to around 3.5k, this is very apparent in the 30’s which is making them hard work with the jerkiness.
I have temp checked the headers and cyclinder 1 seems to not be getting as hot but only be around 40 degrees compared to the rest so suspect this is the one missing.
I have changed the coils to brand new ones, changed the spark plugs round to test if one is faulty (same result every time) changed the plug caps round from the full running cylinders to no avail.
Cleaned up all earth connections for the coils and the battery strap.
I have had the carbs done at my local bit shop with all pilots and o rings sorted, diaphragms also done and cleaned out and then balanced so it runs lovely higher up.
Air filter all good and fuel pump is priming as it should. Set the TPS many times and the clock test says it’s ok.
However this is where I need some help - I have checked the ohms rating on the TPS and when I test the black and blue wires it reads 5.5k ohms.
Then when I check the yellow and blue wire whilst slowly opening the throttle it runs from 0.6 ohm up to a max of 6.9k ohms, but this is momentary, whilst opening the throttle slowly it doesn’t seem to go up progressively, instead it jumps up and down from the lowest reading in between all of them, spiking it.
The spiking seems to happen when I have the throttle a tiny amount open (ie how it would be when in a 30 holding constant speed at those rpms)
I’m not sure if this is the reason it’s jumping when at constant throttle or not but wondered if anyone could lend some advice?
It might also be worth mentioning my bike doesn’t have the exup fitted, this lowers low down grunt but I can’t imagine it’s causing the misfire as described!
Many thanks in advance chaps!
RE: Rough running 2.5k to 3.5k - unfazed - 20-09-25
Common enough issue and the only way to fix it is a new TPS. The TPS is a physical unit not electronic and it wears. When the ohms jump around like you say it effects the ignition timing.
The Yamaha branded TPS is ridiculously expensive, but the
Tourmax TPS-107 and Suzuki 13580-26F00 which has been superceded by 13580-26F01 are direct replacement for the Yamaha 4XY-85885-00
and the Tourmax TPS-113 and Suzuki 13580-42F00 will also work, but need 2 wires reversed in the plug (Usually Black and Blue)as they operate in the opposite direction to the FZS1000.
The FZS1000 TPS is not spring loaded like the FZS600 which also have two different ones which will fit but only one will work as they cannot be modified
RE: Rough running 2.5k to 3.5k - Hubb96 - 20-09-25
Hi Falcon,
Thanks for all the info on what models I can purchase instead of the £200 unit from Yamaha.
I thought I’d double check today and test again, this time from cold the unit was all within specified range. With no jumping around, so I thought I’d then get it up to operating temp and try again.
The readings then simply weren’t there, I could not get a resistance reading for either method and it seems completely dead. I’m not a wizard in any way with this and wondered if that is a way of saying that that the TPS is effectively dead at operating temp?
As like I said, when it was stone cold it worked!
Tearing my hair out with this a bit as I don’t want to sink money into unnecessary parts!
Thanks for replying as quick as you did!
Now after about 10 mins of cooling down the resistance readings are back to normal… I’m confused!
RE: Rough running 2.5k to 3.5k - Gaz66 - 22-09-25
Hi Hubb:
Welcome.
Re: Ohms testing a carb'd bikes TPS.
From what you state in your post, you're actually doing the test wrong.
Test procedure below:
Ohms testing any electrical component is to determine if it's outside of manufactures specs ie) Open circuit / high resistance.
All components under Ohms test must be unplugged.
Ignition pickup coil = (248 ~ 372ohms) unplugged, test across 2 pin connector behind right side panel near fuel pump.
TPS = (4~6Kohms) unplugged.
Ohms test is a static test, you gain nothing by rotating a tps during an Ohms test.
Set meter on 20K Ohms, touch leads together for a few seconds, what does display read?
Any resistance displayed is in the meter/leads & must be deducted from components tested value.
Connect multi-meter (Black/Negative) test lead to TPS Blue wire & meters (Red/Positive) test lead to TPS Yellow.
Display should read (4~6Kohms), if in spec, continue to DCV test TPS, if out of spec, replace TPS.
Voltage Test TPS:
Since TPS is a basic rotating 3 wire potentiometer it needs volt testing in motion to verify a fault.
Fully charge battery before any Volt testing.
Cold test first, then run motor up to temp, retest & compare values.
Connect TPS back up to bikes loom.
Set meter to DCV.
Touch meter leads together for a few seconds to zero meter.
Avoid touching meter lead ends, some meters pick up body voltage.
Connect meter (Black/Negative) lead to battery Negative.
back probe at 3 pin connector with TPS plugged into loom).
Turn ignition "ON".
Back probe TPS plug on Blue & Yellow wires, one of these should be a 5v reference, use the other wire that is the signal wire to test TPS.
Throttle closed, what does meter display = ? DCV, should be around 0.2v ~ 0.5v
Slowly open throttle up to full throttle, display voltage should increase to around 4.5v, any sudden drops or jumps, TPS is faulty, it's usually dirt ingress up the shaft that causes a TPS to play up.
I use a small Ultrasonic cleaner for jewellery, ideal for sensors & injectors, use stainless lockwire to suspend TPS with shaft end upwards, often get a good amount of crap out of em, sometimes this sorts em, sometimes not, suck it n see deal.
Hope the above helps?
RE: Rough running 2.5k to 3.5k - Hubb96 - 22-09-25
Hi Gaz,
Thanks for all the info! Having tested now I am unsure as to what the culprit of my dropping idle and hesitation is.
The ignition pickup tested at 320ohms so all good there.
Following all the instructions the ohms test was 4.8k cold and warm.
The volts is 0.68 with the throttle closed (which is higher then the max 0.5v you specified) and then runs smoothly up to 3.9v without and huge jumps or losses on the way to full throttle and back to closed.
Does the 0.68v mean the sensor needs attention or would this not cause the issue? As spiking isn’t happening and so I’m inclined to think my issue may be elsewhere?
Thanks for the reply, gremlins like this aren’t major but makes riding the bike less enjoyable when it isn’t quite how it should be!
RE: Rough running 2.5k to 3.5k - Gaz66 - 23-09-25
(22-09-25, 09:29 AM)Hubb96 Wrote: Hi Gaz,
Thanks for all the info! Having tested now I am unsure as to what the culprit of my dropping idle and hesitation is.
The ignition pickup tested at 320ohms so all good there.
Following all the instructions the ohms test was 4.8k cold and warm.
The volts is 0.68 with the throttle closed (which is higher then the max 0.5v you specified) and then runs smoothly up to 3.9v without and huge jumps or losses on the way to full throttle and back to closed.
Does the 0.68v mean the sensor needs attention or would this not cause the issue? As spiking isn’t happening and so I’m inclined to think my issue may be elsewhere?
Thanks for the reply, gremlins like this aren’t major but makes riding the bike less enjoyable when it isn’t quite how it should be!
Hi Hubb.
Gremlins can be hard to locate.
If you're convinced you've electrical Gremlins, which it sounds like you have, I'd be working my way thru all the electrics & test everything to manual specs.
2 main loom multi-plugs under left front infill panel, known Gremlin location for corrosion, I found some green corrosion in em on mine when I was unpicking the loom yrs ago to get rid of a shitty Meta alarm system, so I thought fuck it, while bikes stripped & half of loom is out anyway, I started at the arse end & methodically opened up every loom connector, pulled every wire out 1 at a time, wire brushed out any green crap, flushed with brake cleaner, painted every connection with AC50, never had any electrical issue since, that was nearly 10yrs ago.
Out of curiosity, have you replaced or had the plugs out, checked cleaned, ohms tested & gapped em etc, never assume all new plugs are good, test & gap em every time, fake dodgy plugs are out there.
Plug threads & cyl head threads should be clean & grease free, plugs earth thru cyl head, if gummed up with copper grease it can kill the ground for the plugs, many use copper grease,it's not conductive, clean is better, no car or bike motor comes out the factory with greased plugs.
Main Battery to engine earth cable terminates at starter motor bolt, unless cable Ohms test with no resistance which it won't, it's 20+ yrs old, it'll defo have some corrosion inside the copper strands or in the ring terminal crimps, copper multi-strand earth cable & ring terminals are cheap, common sense to replace it, at least then you're 100% sure you have a good ground from batter to starter, starter bolt holes need some love too, drop starter out, run a tap thru em, blow em clean, same love to bolt threads & under bolt head, it's the only earth between battery & engine, so it need to be clean & grease free for a good ground.
Let us know how you get on?
RE: Rough running 2.5k to 3.5k - Trebus - 28-09-25
Been through a similar problem recently which now looks like is eliminated.
In the end I had high resistance through the ignition switch, marginal voltage at the battery due to loom losses and reg / rec getting a bit tired and resistance on one plug cap. The problem was finally eliminated after replacing one of the coils (including leads / caps) even though the old coil checked out fine from a resistance standpoint.
These bikes are getting older and electrical gremlins more common. Good luck.
RE: Rough running 2.5k to 3.5k - Hubb96 - 26-01-26
Hi everyone, sorry for not coming back a lot sooner, life and crap put all issues on the back burner for a while!
So I have tested the battery (voltage all good with no drops) the reg/rec and that’s all performing as it should, new plus been ohms tested and in theory all is well there.
Started in the dark to check for sparks or arcing with no issues.
Cleaned earth strap/ bolts holes
New coils with new caps - again tested and all is well
New tps, tested and adjusted at full operating temp at 1.1k idle
Baffled the exhaust to make sure there isn’t too much pressure getting out
Checked air filter
Ignition not taken apart however have jiggled/prodded and poked while running with seemingly no affect, same with kill switch.
Cleaned out and electrical cleanered all connector blocks.
Checked for air leaks (the system is still on this and wondered if I should take this off?)
The carbs have been off and cleaned and balanced at a local bike shop to me also.
My question is if you guys think I’m missing something? I have gone through all I can think and this stutter at idle and lower and higher revs is still there. Having temp checked all cylinders #1 is the one getting hot and the rest are around 40 degrees behind when at running temp. I’d like to send a video but not sure how!
The stutter is at a constant throttle only, it revs cleanly all the way through and comes back down pretty clean too, only with minimal overrun also!
Hopefully someone can enlighten me with something I haven’t thought of! Again sorry for such a long delay, now getting my teeth stuck in before spring rolls around and I’m still in the garage arguing with the Fazer!!
It might also be worth mentioning that the stutter/misfire gets faster and more pronounced the higher the rev band the bike is held at!
RE: Rough running 2.5k to 3.5k - unfazed - 27-01-26
Does it work better with the choke on?
RE: Rough running 2.5k to 3.5k - Hubb96 - 27-01-26
(27-01-26, 01:15 AM)unfazed Wrote: Does it work better with the choke on?
I hadn’t given this a thought but yes, it holds revs without a stutter on choke fine. There is slight hesitation when first started and little during but it is much better than with the choke off as a whole. I haven’t come across a cold started carbed 4 cylinder yet that starts perfectly balanced yet!
RE: Rough running 2.5k to 3.5k - unfazed - 27-01-26
Sounds like the pilot jets are still blocked. Set the the pilot screws to the factory setting of 2 turns out from fully in, but on standard setup carbs 2.5 works better. The air cut off valve gets clogged up and may need to be cleaned out. although a non working ones usuallycauses a jump on acceleration when opening the throttle after after slowing down to almost stopped and Rarely cleaned as it means seperating the 4 carbs to get at all four. You will see this on the left side of the carb, it is a round cover with two screws. Inside is a small diaphragm and a spring. These are still available if they need to be replaced.The crankcase is vented into the air inatake after the airfilter and can effect this if idle for some time.
RE: Rough running 2.5k to 3.5k - botchitleggit - 28-01-26
as unfazed said... the guy who cleaned the carbs may not have been as diligent as he should have been.
RE: Rough running 2.5k to 3.5k - Hubb96 - 28-01-26
Thanks for this, looks like I’ll be taking the carbs off for a look in the near future. That’s why I tend to begrudge taking my bikes to local shops, should’ve thought it odd when they held onto it for so long!
Thanks for the info and will update after a thorough clean!
RE: Rough running 2.5k to 3.5k - kralik - 30-01-26
Hello all,
I am sorry I enter your thread Hubb, just have a similar question related to air cot off valves in our bikes.
I just gave a proper cleaning and new o-rings to my carbs (with Ivan`s full slip on kit), but I read some old threads related to carbs and found out the air cut off valve should be cleaned or changed too if needed.
And this is my question, just getting the carbs back together, but decided to open and clean up the cut off valves too.
I cleaned them up, but not sure when is the right time to change the diaphragm in them, even they are not damaged or with holes.
The rubber seems to be bit "tired" only, but not torn.
What would you recommend when they should be changed, please?
Just to give more light why I am getting them cleaned. The chokes were stucked and could not move in their holes, the bike were difficult to start in cold and it was running on three cylinders under 3000/3500 rpms.
Thank you in advance and again I am sorry Hubb for jumping into your thread. If this is not ok, I will delete my post then
RE: Rough running 2.5k to 3.5k - unfazed - 30-01-26
Difficult one to answer, but I will try.
The diaphragms do not appear to be the same material as the main diaphragms and are not as supple. I do not believe there is a right time to replace them, however if there is corrosion on the spring in particular I would replace them. My usual route is "if in doubt replace them", but they can range in price from 20 to 30euro. Wash the diaphragms in warm soapy water, dry them out and soak them in WD40 for about 10 minutes and then wipe the WD40 off with kitchen toweling. Many will frown at using WD40 on diaphragms, but I never had an issue doing it. Most important is to ensure the pathways for the air are clear
RE: Rough running 2.5k to 3.5k - RMT1983 - 31-01-26
Evening all,
So my thoughts, when the carbs were off and cleaned, have the tiny little springs been refitted and relocated in the right place? I visited a chap in Norfolk who was experiencing similar issues and I found that springs were missing for the needles. Hsi bike had also been worked on and his carbs done by a local garage.
Not the diaphragm springs, but the tiny ones on the top of the needles! It caused all kinds of low down throttle issues that were almost impossible to find.
Also, the air cut off valves could cause issues although less likely unless they have been damaged when removed or not cleaned thoroughly.
I have air cut off valves available if you do want to try them but id first be looking at the needles so see if they have that spring in them.