Author Topic: Carburetor Spring (Read 5163 times)

adasilva · « **on:** 11 March 2018, 11:20:13 pm »

Hi all.
I need to know if this is an issue or not.
Recently i had a stick throttle and i tried to adjust the slack in the carb and in the handle bar but could not get it to work. I checked to see if the handle bar end was the issue as i read somewhere that it might be sticking on the handle bar ends but that was not the issue. I lubed the cables and check for tears and could not find any.
What i noticed was that there were so much dirty on the outside of the carburetors and the springs were covered with it.
I removed the carbs as in needed to change the carb rubber boots and clean them. The carbs insides were not too bad but outside the were so much S___t and the throttle spring was full of it.
I made a good progress and the carbs now look great.
But i have tried to open the carb vents by pushing the spring but when i let it go it stays in place with the vents open. I have lubed the springs again after the cleaning but still the same.
This is my first time getting my hands dirty in removing carbs and cleaning them. So wondering if this is a normal thing or should the spring snap back when i let them go and close the vents.

Cheers
adasilva

Disorderlypunk · « **Reply #1 on:** 12 March 2018, 08:44:34 am »

if you are meaning the butterfly valves (brass bits) then yes that should snap back to the closed position (especially if no cables on)
is there any chance of some photos or a video to give us a clearer idea, we might spot something missing or misplaced

adasilva · « **Reply #2 on:** 12 March 2018, 08:59:39 am »

Yes that is what i meant. The cables are disconnected as the carbs are out.
I will post some images later today when i get back home.

thanks Disorderlypunk

adasilva · « **Reply #3 on:** 12 March 2018, 01:31:31 pm »

Here is the link for the pictures.

https://drive.google.com/file/d/15jRCc1JEuhpaTCbnp4AQikEdvR6EQFgJ/view?usp=sharing
https://drive.google.com/file/d/1v6ZaJX76izau8-hx-Zv9z2VcFmdE1yKz/view?usp=sharing
https://drive.google.com/file/d/1b1Y2RwDa-MGf6sC_Au4tZNV3vDu6Tdia/view?usp=sharing

The images above shows the carb with the butterflies closed, opened by pushing the spring and left opened when released the spring.
Question is should the spring snap back and close the butterflies (vents)?

Cheers
adasilva

Fazerider · « **Reply #4 on:** 12 March 2018, 02:14:30 pm »

How much force does it take to rotate the butterflies?
The springs are quite stiff so it should feel uncomfortable pushing the pulley with your thumb. If it opens with little resistance check the two springs are not broken and the inner ends are fixed to the pulley and outer ends fixed to the bodies of carb 2&3.
On the other hand, if there’s massive resistance to rotation that the springs can’t overcome then it sounds as if the shaft either has got corrosion jamming the pivots… or the entire assembly has been dropped and things are no longer straight.

adasilva · « **Reply #5 on:** 12 March 2018, 02:51:39 pm »

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.

adasilva

Fazerider · « **Reply #6 on:** 12 March 2018, 03:23:55 pm »

Ah! I’d forgotten the TPS was also a factor.
It should be possible to tighten the screws up firmly, you don’t want it drifting out of calibration.
Just make sure it’s centred and you should be OK.

Disorderlypunk · « **Reply #7 on:** 12 March 2018, 03:31:55 pm »

well that is definatly one for the memory - wouldnt have thought about the tps untill checking pretty much everything else lol
good find

adasilva · « **Reply #8 on:** 12 March 2018, 04:31:30 pm »

Great guys thanks for all your inputs!

adasilva · « **Reply #9 on:** 12 March 2018, 04:45:20 pm »

FazerRider
Can you explain what you mean by centre the TPS?
cheers

Fazerider · « **Reply #10 on:** 12 March 2018, 06:18:27 pm »

I’m just guessing that the TPS was bolted down such that it was applying sideways pressure on the shaft, i.e that its axis was slightly off to one side rather than concentric with the shaft. There should be enough free play available between the screws and the slots in the TPS (when they’re loose) to be able to get the TPS centred.
Another cause for the problem might be that the TPS is pressing on the end of the shaft, but it’s hard to see how that could happen unless there’s a lot of dirt in there or the TPS is non-standard.

tommyardin · « **Reply #11 on:** 12 March 2018, 09:48:44 pm »

Interesting post and helpful information.

I was wondering if the return springs had just not been fitted/anchored in the right position after strip down and rebuild. But that is obviously not the case as the Butterflys snap back shut with the TPS removed.
Its always a good policy when fitting any part to put all the fixing screws in place without tightening them up, and centre the part by wiggling it about within the tolerance of the fixing holes to centre the part.
Now I'm not convinced that makes a lot of sense but at least I know what I mean

Looks like you have done a nice job on the carb clean they look good, well done

Oh ! one other thing I know what the TPS is but what do those initials stand for? or what do they mean?

Jules-C · « **Reply #12 on:** 12 March 2018, 10:21:34 pm »

Throttle Position Sensor

adasilva · « **Reply #13 on:** 15 March 2018, 11:14:59 pm »

Hey guys. This is taking my night's sleep now.
I have put the TPS back in place and tried as peer your suggestions to centre it but no matter what i do the bloody thing stops the spring from snapping back. It only allows it to spring back if the screws are bit loosed. Once i tied them down ( and i am doing that using the same amount of turns on each screw at time) it locks the spring.

any ideas on what i am be doing wrong?

unfazed · « **Reply #14 on:** 15 March 2018, 11:29:21 pm »

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.

Disorderlypunk · « **Reply #15 on:** 15 March 2018, 11:29:51 pm »

i have no experiance with the tps but it might be worth looking at it on its own and seeing if the movement feels 'notchy'
if it is it might be worth giving a clean with some electrical cleaner (might be some sh*te in it)
if there is damage to the rotational parts it might need replaced and you wont be happy as i am sure i read they are a bit pricey

tommyardin · « **Reply #16 on:** 15 March 2018, 11:35:02 pm »

Quote from: Disorderlypunk on 15 March 2018, 11:29:51 pm

i have no experiance with the tps but it might be worth looking at it on its own and seeing if the movement feels 'notchy'
if it is it might be worth giving a clean with some electrical cleaner (might be some sh*te in it)
if there is damage to the rotational parts it might need replaced and you wont be happy as i am sure i read they are a bit pricey

Have a chat with Darrsi he is clued up on the TPS situation and knows where to source them at a good price.

celticbiker · « **Reply #17 on:** 16 March 2018, 06:51:53 am »

It sounds to me like it's either the wrong tps or it's supposed to have a spacer (1-1.5mm ish) behind it.
I'm assuming the screws are m4 or m5. Try putting a washer of the relevant size on each screw between the tps and the carbs then try it, this will prove a theory, a solution can be worked out later.

adasilva · « **Reply #18 on:** 16 March 2018, 01:49:19 pm »

Hey all!
Update news!
First i think the TPS is spring preloaded as when i rotate it using a screwdriver and let it go it snaps back into the original position. Second, it only rotates to one direction.
while i was trying it out again, and removed the TPS i noticed that this little o ring rubber came on with the TPS. This rubber was located inside of the carb where the TPS connects to. When i tried without it i had no issues and the TPS seems to snaggle into place very well. With the rubber on, it does not attach properly and before screw the TPS in there is about 3mm cap between the TPS and the carb. See pictures
Any ideas what this rubber is for?

cheers

darrsi · « **Reply #19 on:** 16 March 2018, 02:11:24 pm »

From experience don't even bother buying a "used" TPS simply because of the age of the bikes now.

You could be buying a part that is 15-20 years old that is just waiting to play games with you or pack up completely, so just buy a new one if necessary.

Don't worry about buying a year specific TPS, as they'll work on all 98-03 bikes.

https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313.TR0.TRC0.H0.Xfzs+600+throttle+position+sensor.TRS0&_nkw=fzs+600+throttle+position+sensor&_sacat=0

unfazed · « **Reply #20 on:** 16 March 2018, 02:26:43 pm »

Ys a common issues, rubber ring get squashed against the shaft. Glad you got it sorted. The reason for my original question was to see if you wete fitting it the correct way around. You would not believe what I have seen with TPS fitting. 😊

adasilva · « **Reply #21 on:** 16 March 2018, 02:47:20 pm »

Thanks darrsi.
I am going to buy that one that you send me. Thanks for that.

I kind thinking that that rubber ring could not be possibly be part of the carb. because when i removed it if fits on the TPS but it leaves a 3mm gap from where it sits on the TPS and the end of bottom of the TPS if you know what i mean. So when i connect it to the carb that 3mm gap wont fit properly as the rubber does not pass the edge of the role where the TPS sits so the TPS is not flushed with the carb and to do so causes a lot pressure on the screws and locks the butterflies.

see images
First one is the TPS without the rubber and without screw in. See how it fits perfectly. and if i tied the screws the spring snap back closed the vents.
Second shows the TPS with the rubber on. you see where it sits and the gap it leaves.
Third on is the TPS with the rubber connected to the carb. See the cap and to make it flush there is to be a quite pressure when screwing the tps in place.

adasilva · « **Reply #22 on:** 16 March 2018, 04:01:32 pm »

Hey All.
I finally figured out!

Whomever had changed the TPS before me had jammed the rubber all way inside the groove where the TPS sits on the carb. I mean jammed in! I could not even see it.
So no wondering the TPS was not going in properly and was jammed the butterflies vents.

Thanks all for your great help!

I just ordered a new TPS as this one was giving me trouble.

Thanks again

darrsi · « **Reply #23 on:** 16 March 2018, 05:51:54 pm »

Just be aware if you've recently done a carb balance with a possibly faulty TPS then the carbs won't be set right so will need doing again once the new one is fitted.

redmandan · « **Reply #24 on:** 18 March 2018, 08:16:15 pm »

Great thread and glad you got it fixed mate. I myself am also fairly new to Fazers and one of the things I liked about them was the help and community available on this site.

A word of advice (As I have to take my carbs off again cos I didn't do this) do your best to bench sync the carbs before you put them back on. This will help to balance them later and also familiarize yourself with the location of the balancing screws so it's less of a fiddle.