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adasiva 12th March 2018 09:51 AM

Throttle spring
Hello there.
I have removed my carbs from my FZS 600 2002 and i have noticed that the spring the open the butterflies on the carb are not returning back when opening it by hand. Should they snap back? I think so but not sure since this is my first attempt to clean the carbs.
They were very dirty and i clean and lubed it but still when i push with my thumb they kept it open.

If the issue is the spring, is that a difficult thing to change? I have searched the net but cannot find any info on how to change them.

I have checked and they seem to be connected properly. I did not removed them while cleaning the carbs so don't know.

Has anyone had this issue before or has anyone changed these springs before?


Burt_Munro 12th March 2018 10:40 AM

Re: Throttle spring
Like you, I would have thought they should snap back but I'm no expert. A picture might help with some more useful answers from some of the other members!

DavyH 12th March 2018 12:05 PM

Re: Throttle spring
Are we definitely talking about the butterflies here,you sure it's not the diaphragm slides? They are under spring tension also but the fuel going past them tends to lubricate them and when they are old they bind a little when dry

adasiva 12th March 2018 01:07 PM

Re: Throttle spring
Hey thanks for the reply.


Images above shows the butterflies closed, opened by pushing the spring and left opened (spring does not return)

Hope this will help clarify


adasiva 12th March 2018 01:09 PM

Re: Throttle spring
Going to just add the link to drive is faster to open


adasiva 12th March 2018 02:32 PM

Re: Throttle spring
Hey Guys.
I just went home for lunch and decided to have another look. while i was contemplating what would be causing this issue a light bulb come on. Could it be the TPS as i had changed it.
So i removed it from the carbs and bingo! the spring snapped back.
I then put it back on and did not tied the TPS screws as much as it was before and they still snapping back.

So now i will have to reset the TPS but and try not to tie the screws too much.

Strange one

Good thing is that is not the springs that is the problem. But i am afraid that when i put the carbs back and reset the TPS this will happen again as I remember that i had to tied the screws in such way as to have a 5000 RPM steady reading.

Thanks for your help and i will let you know once i have put it back on the bike.


Notch000 12th March 2018 02:34 PM

Re: Throttle spring
they should snap back, there are two cable runners, one for the throttle and one for the choke, are you sure you not adjusting the choke ?

chopper 12th March 2018 02:55 PM

Re: Throttle spring
He had the tps back in slightly off centre or something

adasiva 12th March 2018 04:16 PM

Re: Throttle spring
[quote=chopper;3525848]He had the tps back in slightly off centre or something[/quote]

Just one question when you say off centre what do you mean?

jp biker 12th March 2018 06:28 PM

Re: Throttle spring
Choppers area of expertise
Drop him a pm or call/txt him

adasiva 14th March 2018 10:01 AM

Re: Throttle spring
[quote=jp biker;3525908]Choppers area of expertise
Drop him a pm or call/txt him[/quote]

will do thanks

manbearpig 14th March 2018 11:08 AM

Re: Throttle spring
1 Attachment(s)
[quote=adasiva;3525872]Just one question when you say off centre what do you mean?

TPS should fit into a groove - you had it off center

Sorry about the pic - only one I could find online, it will only go on when seated properly

adasiva 15th March 2018 08:48 AM

Re: Throttle spring
Hey manbearpig
thanks for the picture i know what you mean now.

adasiva 15th March 2018 10:14 PM

Re: Throttle spring
Hey guys.
Thanks all for your inputs.
I still having some issues. When i remove the TPS the spring snap back closing the vents of the carbs, but as soon as i put the TPS and tied the screws it gets stuck. If i loose the screws its fine but then i don't see how the TPS will stay in place.
I checked that i had the TPS correct in place and to me there is only one way that it goes in which fits the groves as point out bh manbearpig.

Any ideas??

Unfazed 15th March 2018 11:08 PM

Re: Throttle spring
Remove the TPS rotate the inner until it stops, (note which direction you rotated it) put it on the carb and try it. If it does not work remove it and rotate it in the opposite direction until it stops now try it on the carb again.

DavyH 16th March 2018 07:43 AM

Re: Throttle spring
You need to fit the TPS with a load on the spring(the internal spring for the TPS). Just don't rotate it the wrong direction or you could damage it. Use a flat head screwdriver to get a feel for how it operates,then fit it to the locating tab and turn it to line up the bolt holes. Don't overtighten the screws! You will still have to adjust it but it makes very little difference on an fzs,you could run the bike without it if you're really stuck but you'd have to bypass it or your clocks will be hopping all the time

Unfazed 16th March 2018 08:29 AM

Re: Throttle spring
You are obviously not familiar with the TPS on the Fazer

DavyH 16th March 2018 08:32 AM

Re: Throttle spring
[quote=Unfazed;3526458]You are obviously not familiar with the TPS on the Fazer[/quote]

Why,is it not spring loaded?

DavyH 16th March 2018 08:36 AM

Re: Throttle spring
Might be thinking of the Suzuki ones:thumbsup2:

adasiva 16th March 2018 09:12 AM

Re: Throttle spring
Hey all.
Thanks for all you advice. I am not familiar with the TPS until it started giving me issues and i had to research and buy a new one. It seems strange that none of the google searches that i did was talking about your advice on how to attach it to the carbs Unfazed/ DavyH. I did not know that! But living and learning that's is my 'motto'!
I will try to set them with the spring pre-loaded and see.
I will let you guys know.
Thanks again for all you help.