Hi everyone. I’ve recently become a happy owner of a 2005 FZS1000. The bike is awesome, and I’d like to improve it further. Unfortunately, when I went to service the EXUP system, I discovered that the valve had been removed and the muffler welded. In Estonia and neighboring countries, it’s very difficult to find a header with this valve.
So I’ve got a question before I start. How badly does the absence of the EXUP system REALLY affect low-end performance? I ride about 80% in the city, and I’d really like the engine to pull well at low RPM right away.
I found a company on eBay that makes jet kits for the Fazer and other bikes as well. They’ve sold over 100k kits and have around 40,000 reviews. From what I understand, they select the kit based on the bike’s setup.
So here’s my main question: if I order a kit for a completely stock bike but with the EXUP disabled, what will come out of it? Will everything run fine, or is it better to restore the EXUP by any means?
Thanks 
Jet KIT 6 SIGMA
27-08-25, 09:24 AM
(This post was last modified: 27-08-25, 09:45 AM by PieEater.)
(26-08-25, 05:26 PM)vitman Wrote: Hi everyone. I’ve recently become a happy owner of a 2005 FZS1000. The bike is awesome, and I’d like to improve it further. Unfortunately, when I went to service the EXUP system, I discovered that the valve had been removed and the muffler welded. In Estonia and neighboring countries, it’s very difficult to find a header with this valve.
So I’ve got a question before I start. How badly does the absence of the EXUP system REALLY affect low-end performance? I ride about 80% in the city, and I’d really like the engine to pull well at low RPM right away.
I found a company on eBay that makes jet kits for the Fazer and other bikes as well. They’ve sold over 100k kits and have around 40,000 reviews. From what I understand, they select the kit based on the bike’s setup.
So here’s my main question: if I order a kit for a completely stock bike but with the EXUP disabled, what will come out of it? Will everything run fine, or is it better to restore the EXUP by any means?
Thanks
Jet KIT 6 SIGMA
Hi, and welcome to the forums, I'm glad your enjoying your Fazer. Under the "Important Threads" section you will see a FAQ for the Gen1 Fazer 1000 which I'd encourage you to read as a new owner as it has lots of useful information.
To answer your questions with the EXUP valve missing your bike is not going to be ideal for town use as it will be missing the low down torque that the EXUP system is designed to provide so will instead be quite flat at low revs and then take off at higher revs. Unfortunately the only way to resolve this is to restore the EXUP system which as you say can be difficult / expensive to source. There are no jet kits specifically for a FZS1000 without the EXUP and the only jet kit likely to be recommended on these forums is the Ivan's kit which is mentioned in the FAQ but even this won't restore the low down pull that the EXUP valve provides.
If replacing the EXUP isn't going to be possible but you still want to improve the bike, then looking at the rear suspension would be a good place to start, especially if the shock is still the original one, as replacing or refurbishing it will make a noticeable improvement on the handling.
They run like crap at anything but half throttle, another one of those myths people used to believe, ok ish for the track utterly useless for the road. That said most are in the state yours is because owners didn't service them and couldn't afford or didn't want to pay for repairs/replacement.
As mentioned there's no off the shelf jet kits for non power valve bikes that I know off. Time on a Dyno and more than likely replacement cards required to get the non valved engine running at its best. Costs of that route are probably more than finding a replacement set of down pipes.
Later
27-08-25, 02:41 PM
(This post was last modified: 27-08-25, 02:50 PM by vitman.)
I hear you. I'm not really a fan of tuning myself. It's just that many people speak positively about it.
So the right way would be to take the carbs off for the winter, rebuild them with a Keyster kit, and find an EXUP collector to restore it to working condition, right?
https://www.ebay.de/itm/335725548550?_sk...R-bvjo6ZZg
After 4000 rpm the dynamics are completely fine. Up to 4000 it feels a bit sluggish (exup), and I think the carburetors need to be rebuilt because – the idle is not stable, when riding at a steady speed the bike shakes, and also at low rpm it shake  . I understand that synchronization alone won’t be enough. And I also want to do it properly once (rebuild the carburetors).
27-08-25, 04:34 PM
(This post was last modified: 27-08-25, 04:42 PM by Gnasher.)
Jets unless poked/cleaned roughly with something unsuitable don't really wear out, OE parts are going to be way better quality than pattern parts. If you bike is running as you say you probably need to to nothing more than just a good clean of the carbs, inspect all the jets. Pay particular attention to the metering jet and the needle that goes in it, the one the float attaches to. Also check all the main needles are set to the correct height ie the clip is in the correct slot on each one. Find a set of downtubes with a working EXUP reconnect the servo, hopefully that's still there and working?
Set the cables, a good carb balance and away you go as Yamaha intended.
Later
Thanks for the solid advice. This is my first bike, and on carbs too.
Could the picture change with some new info? Today my vacuum gauges arrived, so I decided to check carb sync and overall intake vacuum. I only have about 17–18 cm of vacuum at 1200–1300 rpm with the engine warmed up. Tried spraying brake cleaner around the whole intake, but there was no reaction.
Also, just out of curiosity, I checked the TPS setting according to the manual, and it turned out it was set at 10,000 rpm. I reset it to 5,000, and the bike started running noticeably better.
Still, it’s unpleasant to ride around town at a steady speed because of the shaking — you’re either accelerating or decelerating. At idle the throttle response is instant, and the revs drop back down smoothly and quickly. Acceleration after 4,000 rpm all the way to redline is clean, with no flat spots. No backfiring into the exhaust either. Sometimes though, the idle can sit 200–300 rpm higher than it should when hot. Not sure why — you ride for a while, stop, and suddenly the idle is at 1500.
Just my own experience.
My EXUP became poorly during covid lockdown - rebuilding the valve was going to be prohibitively expensive and a very long process. (nil parts availability and no access to a machine shop locally).
So I replaced the entire exhaust system with a Black Widow.
I then fitted a 4 degree ignition advancer.
Rode it like that in town, city and everywhere else with no issues at either low, mid or high rpm. If anything it would rev freer.
2002/3 I then fitted an Ivan's kit, along with new manifold rubbers (machined to match inlets on cylinder head!).
Pulls from 25 mph to 1?? in top without any bogging, hiccups or any other issues.
Just ordered a Piper Cross air filter - won't make a massive difference, but then again I'm not looking at improving something that doesn't really need improving.
90,000 miles and still going strong.
Thanks for the tip. I ordered a 4-degree sprocket. It’s not expensive, and I can always switch back if needed
27-08-25, 11:06 PM
(This post was last modified: 27-08-25, 11:49 PM by Gaz66.)
Welcome brother.
From personal experience, the bike needs a working/correctly setup Exup system, sounds like you've bought a potential shitter that's been abused/bodged, don't assume you're just only missing the Exup valve assembly, there's a servo motor just forward of the left side coil under the tank that runs a pull/push twin cable setup that operates the Exup valve, i'd check all parts are present before spending money.
Early Yamaha R1's use the exact same Exup valve, as does the Thunderace, i think the servo's are the same too, dunno about cables, headers are defo different, not massively but they're are different, you might get away using R1 headers, but you'll have to do some welding as the lower mount near centre stand is different from memory, Thunderace headers will likely be no use as these run the older FZR motor, 99% sure the Exup valves are all the same on all 3 bikes tho, at least you've half a chance on Ebay finding a usable valve assembly, even though the headers won't be much use unless you're handy with an arc welder.
My advice is don't spend on this bike until you've confirmed the motor's not shagged in any way, leave tuning the carbs until you sort the missing Exup system.
I've often seen usable FZS1000 headers on eBay with the valve missing, seen as new minter headers with the Exup still fitted on USA eBay listings, shipping is a biatch tho, don't forget other bikes in Yamaha's range use the same parts.
Good luck bro ?
Just seen these headers (Poland) so not far from you... look in decent nick, just missing the valve assembly.
https://www.ebay.co.uk/itm/177334974829?
Maybe luck has finally turned my way ? Today I found an intake manifold with a flap, motor, and cables. Hopefully everything will work out and the bike will come back to life.
As for the carburetor, that’s still an open question. Can anyone share from their own experience — do fuel additives for cleaning carburetors actually work?
(28-08-25, 06:47 AM)vitman Wrote: do fuel additives for cleaning carburetors actually work?
No they don't if a jet is blocked now amount of fuel additive is going to clear it. They aren't good even just for cleaning, my humble opinion they're a waste of money.
Later
can you share Ivans facebook page ? thanks
Good evening.
Ivan is now closed until early September due to his annual holiday and also moving premises.
Don't worry though as I am the official importer and supplier of his kits.
I couldn't recommend staying away from the keyster kits enough. I have had a number of these kits for other bikes and have rarely been satisfied with any of the jets provided.
Most kits on ebay are garbage. Stay with your original jets where possible. If its not seized its not a problem! Clean vigorously and make sure all is clear.
I would also stay well clear of aftermarket cheap downpipes. People that notice no difference never had a working exup to compare with (my opinion).
I also sell the seal kits and fortunately have carbs on the shelf ready to sell.
As said above, check out the frequently asked questions part of the page.
Chuck me a message and im happy to chat more.
Thanks for your reply. I’ll restore the EXUP, set the ignition advance to +4°, and repair the carburetors. After that I’ll start thinking about tuning.
Could someone advise on replacing the fuel filter? It’s located inside the tank. Are there any equivalents from MANN or Knecht that I can easily buy in Europe and that will fit, or is OEM the only option?
Im guessing when you say the fuel filter inside the tank, you are specifically talking about the one that fits to the petrol tap? We have a saying in England, if its not broken, dont fix it. Those filters can be cleaned and reused. As can the 4 that live inside the carburettors that many people aren't aware even exist.
Whilst repairing the carburettors, which probably only just need a clean, it would be a shame not to fit the kit whilst your there and the carburettors are apart.
Rear ivans website, there are many benefits to installing the kit, increasing power isnt the most impressive benefit. It totally alters how the bike behaves through the rev ranges and reduces niggles like engine vibration etc.
https://ivansperformanceproducts.com/fz1.htm
Don't go putting extra filters in the fuel system they're not required and can actually restrict the fuel flow causing all manner of issues.
The best set up is standard EXUP with K&N and Ivan's kit fitted there is a few levels so take your pick. Any level improves the bike as mentioned not really about overall power gains, there is a slight gain. It's all about low and mid range and it's a huge improvement.
Later
Just throwing this out there. Ivan does not recommend k&n filters as the fitment is poor. The filters now rattler about in the box and are no longer fully seat.
He does however recommend DNA and after fitting half a dozen myself I also back what he says. They are a tight fit and look as good if not better than k&n.
Myself, I like BMC, although they are Italian and their postal service leaves lots to be desired.
l've fitted something like 50 odd K&Ns never had any issues or complaints/returns. Of those 50 odd I still see/service 8 of them they've all been in there for 20 odd years!
Later
(29-08-25, 11:35 AM)Gnasher Wrote: l've fitted something like 50 odd K&Ns never had any issues or complaints/returns. Of those 50 odd I still see/service 8 of them they've all been in there for 20 odd years!
I dont doubt that.... but how many new ones have you seen? New ones are lacking serious quality control and certainly won't get my recommendation or Ivans.
(29-08-25, 02:56 PM)RMT1983 Wrote: I dont doubt that.... but how many new ones have you seen? New ones are lacking serious quality control and certainly won't get my recommendation or Ivans.
Last week, admittedly not one for an FZS1000. As mentioned they last a lifetime correctly maintained. There's also not much call for FZS1000/600 K&Ns new these days. The one last week was for a Z1000SX, no problem with the fitment.
Where you getting this idea from? Sounds like whomever wants to push DNA for a kick back, very common these days.
Later
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