carb problems (yes, i've edited title 3 times)

[12thmonkey]

After this thread, i decided that i needed to rejet. i got some jets from Alpha yesterday, and tackled the job today. Unfortunately, after the rejet, it's actually running much worse than before. The symptoms are just like  this thread. It runs like CRAP at low rpms. And by crap, i mean it hesitates really bad. Throttle response is very jerky and inconsistent, and maintaining a steady engine speed below 5k is impossible. And this is while in neutral...riding is even worse. i didn't even try to venture further than up and down our street. It seemed much better above about 5k though.

Here's some pertinent info:  It's an '02, that has 135 mains, 62.5 mids, 17.5 pilots, and the needles have not been shimmed. i checked the floats with the tube method, and the level for the left carb is a little over about 7mm (edited from .5" measure on sidestand - oops) above the gasket. The right float seems to be ok. So, i do know that i need to adjust that left float...but have a few questions.

1. Is there a write-up on adjusting the float height (preferably with pictures )? i searched and found a lot of stuff for carb heights on pre-01 carbs...but nothing on the later carbs. Is there a difference other than the screw holding the float assembly down? Basically, i don't know what the reading means or how to fix it. 

2. Is it likely that the float height is the lone culprit? If there is anything else i can do while i have the bike/carbs apart...even if it's just for peace of mind...i'd like to do it.

***EDITED to clarify the phrase "runs like CRAP." While true, it's not the most accurate description...

[werase643]

well, logic would tell me to put it back so it doesn't suck

[12thmonkey]

well, logic would tell me to put it back so it doesn't suck

It sucked before. Now it just sucks worse. i know the float height is off, and i'm sure that's having a big effect...i just don't know exactly how to adjust the float height. i'm hoping the rejetting will help eradicate the problem with running lean. And hopefully fixing the float height will eradicate the problem i'm having now?

[Jenya]

Well, if you suspect float height to be off so certainly, then just go over your fear of tackling the unknown and adjust it.
It is very easy. All can be done right on the bike without having to remove carbs.

To check the float height use this HowTo: http://www.gstwin.com/float_height_check.htm

To adjust, you simply bend the metal tang on which the needle jet is hanging gently with a screwdriver.

Jenya

[The Buddha]

Floats ... nope ... under 5K ...
You have air leak ... definete ... or carbs waaaaaay out of synch ... or choke stuck open ... or fuel getting into vacuum line ...
Plug pull at idle or ... 3-4K ...
I have had a float height off, decently synched, choke sticking, throttle play = 0, and vacuum diaphragm leaky so it takes in gas from the vacuum line ... and the biggest change to it was that ... fixed it, and I ran it for over 50 miles before I did anything else ... Still has float height off.
You have air leak if too lean, (white plugs) or fuel crossing into vaccum line if rich black plugs ... and wet too.
Cool.
Srinath.

[12thmonkey]

Well, if you suspect float height to be off so certainly, then just go over your fear of tackling the unknown and adjust it.
It is very easy. All can be done right on the bike without having to remove carbs.

To check the float height use this HowTo: http://www.gstwin.com/float_height_check.htm

To adjust, you simply bend the metal tang on which the needle jet is hanging gently with a screwdriver.

Jenya

Fear is not what's keeping me from doing it...it's more that unknown aspect. i already used Kerry's method to check the height, that's how i found out it was off. i was just hoping someone could tell me what it means that the fuel level in the hose (from Kerry's method) was about .5" above the gasket. Which direction do i need to bend the tang? And is the measurement of around 14mm the same for the '01+ carbs? i'm still a little confused as to how to arrive at that measurement too. Argh...

[12thmonkey]

Floats ... nope ... under 5K ...
You have air leak ... definete ... or carbs waaaaaay out of synch ... or choke stuck open ... or fuel getting into vacuum line ...
Plug pull at idle or ... 3-4K ...
I have had a float height off, decently synched, choke sticking, throttle play = 0, and vacuum diaphragm leaky so it takes in gas from the vacuum line ... and the biggest change to it was that ... fixed it, and I ran it for over 50 miles before I did anything else ... Still has float height off.
You have air leak if too lean, (white plugs) or fuel crossing into vaccum line if rich black plugs ... and wet too.
Cool.
Srinath.

Srinath - would putting in larger mids and mains make any of the problems you suggested more pronounced? It was already running rough (hesitating throughout the power band, but primarily in low to mid rpms) It seemed like it was running lean, and rejetting was called for. Since then, the only thing i've changed is the jets. Could i have somehow unsynched the carbs in my removing them? i do know that the choke cable isn't stuck...

How long does the bike need to run for the plugs to show the signs of running lean/rich you described? Spray WD-40 around carbs and look for white smoke from pipe to test for vacuum leak (i think i read that somewhere)?

[galahs]

This is why I'm happy to leave my carbs alone.

Want a faster bike, buy a faster bike. lol

[12thmonkey]

Srinath, just out of curiosity...why did you tell me the problem is probably not float height, when you advised Jake42 here that his identical symptoms were caused by a bad float height? i tried fixing the float height but got it wrong. Is it bad that i want to rule this out first? i tried spraying WD-40 around the carbs, and didn't get white smoke...i didn't find where, but i remember reading that somewhere...who knows...

Any help would be appreciated. This is not me trying to make my bike faster...i'm just trying to get it running better. i just bought it and the PO had installed a slip-on without rejetting. Thought rejetting would make it run better...now just trying to clean up a mess i apparently made. i'm tempted to go back to the stock jetting, and find stock exhaust...but first i gotta clear up this float height issue.

[12thmonkey]

UPDATE:  i just adjusted the float height two more times. i discovered that trial-and-error adjustments with everything still on the bike were MUCH easier than trying to make sense of the measure method with everything apart (never really figured that out, i guess). i got it much closer. It's about 3mm above the gasket at this point. It's running better, but it's still having big hiccups down low. About half the time, right when you give it some throttle, it the rpms drop and then come up (there is a literal "hiccup" sound that actually comes from the carbs at this point). i took it out for a ride, and above 3k, it's running much better. i pulled the plugs, and they looked fine. If anything a little white...but definitely not wet or black.

Could the hiccups be from that one float still being a bit off? i guess at some point i need to check to see if the carbs are synched (trying to rule out everything else Srinath suggested). Any other thoughts?

[The Buddha]

I didn't see this thread till now ...
But I dont remember Jake42's case ... maybe he told me somehting in a PM ...
Anyway, the one and only 01+ carb I have worked on, had floats that were very very hard to adjust ... so I didn't think it may be the case.
3mm above gasket ... is waaaay high ... at gasket is right, however you are raising it up and its getting better right ...
Then you'd prolly have to step up mains ... Maybe.
I'll try to re read your thread and Jake42's and see what else jumps at me.
Lean under 3K. Floats affect the mixture on the opening throttle action quite a bit. You can be lean at idle, and rich at the opening ... though ... I'd like to set the floats stationary where they oughta be, and jet around it. too high and they'll leak.
Cool.
Srinath.

[12thmonkey]

Anyway, the one and only 01+ carb I have worked on, had floats that were very very hard to adjust ...

Ok, so it's not just me.

3mm above gasket ... is waaaay high ... at gasket is right, however you are raising it up and its getting better right ...

It was about 1cm when i started...and i adjusted it several times. Finally got it to about 3-4mm, but it didn't seem to want to go any lower. That's why i left it where it is. Maybe i'll try again tomorrow...

Lean under 3K. Floats affect the mixture on the opening throttle action quite a bit. You can be lean at idle, and rich at the opening ... though ... I'd like to set the floats stationary where they oughta be, and jet around it. too high and they'll leak.
Cool.
Srinath.

i don't think i understand what you're saying here. Would the float height allow it to be lean at idle and rich at opening throttle? How would i jet around it? And is 135 too small for mains?

[12thmonkey]

The current situation:  The bike stumbles really bad at low rpms. It has a difficult time holding a steady idle below 3k. When you try and give it throttle, it dips really low (doesn't die) and struggles to get up above 3k. Also, while riding, it does a whole lot of popping out of the pipe when engine braking. All in all, the problems get much better after the bike warms up...it just takes a LOT longer for that to happen. My commute is about 20 miles...most of which is on a freeway with intermittent stoplights. It was running rough and having a tough time with take-offs for i'd say the first 15 miles, or so. And that is after about 5 minutes of warming up before the ride.

[12thmonkey]

Anybody got any ideas?

[The Buddha]

By hard to adjust ... I sorta meant ... didn't need to be adjusted. The floats bend and get higher just from regular bouncing around ... the 01 floats are pretty resistant to that.
Idle dropping below the set idle when you blip the throttle = rich ... as is ... you rev up and let go, it drops below the idle speed and rises back to idle ...
You give gas and it sorta seems to fall on its face gasping = slide rising up too fast.
135 mains and 17.5 pilots ... why did you do that combo.
Stock pilots are 17.5, but stock mains are 127.5. You have some jetting off there.
I have bumped up the mains 1 step and bumped pilots up 1 and left the mids alone and shimmed needle for a bike with pipe and paper filter.
Let me read you thread again.
Cool.
Srinath.

[The Buddha]

OK you have just a pipe - 130 - 1 step up mains and 20 pilots - 1 step up. leave stock mids and put 1 washer under needle. Sorry man I dunno why I didn't tell you this earlier, but somehow I wasn't thinking.
Cool.
Srinath.

[12thmonkey]

Cool. Thanks. That helps (well, hopefully it will ). i'll try and take care of that this weekend. As to why i went with that setup...i can't really remember now (i read so many threads ). i remember Alpha thought that 135/62.5/20 would work well, and offered some 135s and 62.5s. i took him up on the offer, and i guess forgot that i also needed pilots (for some reason, i remember someone saying that i wouldn't need to change the pilots ). i know i don't really understand the what the various jets do...i guess that'd help. i'll try and get the right jets and see if that solves the problem. Thanks for getting back to me Srinath!

[12thmonkey]

While i'm at it, how do you get the needle out on 01+ carbs? i couldn't tell what was holding it in there, and i didn't want to try and force it.

[Wrecent_Wryder]

u7