FZRSupport: the FZROnline Archive

Here's how the things are:
If I have the floats height set to 24 mm. When i start the bike, it starts fine. I let it warm up to working temperature, but when i blip the throttle it boggles. So i start to turn the pilot screws out from 3 turns up to 7 turns out. Only when i get them at 7 turns out, when i blip the throttle it doesn't boggle anymore.
As far as i know, when you turn the pilot screw out, you make the fuel mixture richer, and if you drop the floats height you also make the fuel mixture richer at low RPM.
What is the cause of this oddly high number of turns out of the pilot screws?
Because as far as I know, if the carbs ar worn, the fuel mixture is richer. So if my carbs would be worn I would not have to make the fuel mixture richer by turning out the pilot screws.
Help me out because I'm completely lost!
Thanks guys!
P.S. I forgot to mention that the clip on the needles is at the last position toward the thick end of it.

Anyone??

trifgeorge wrote:Here's how the things are:
If I have the floats height set to 24 mm. When i start the bike, it starts fine. I let it warm up to working temperature, but when i blip the throttle it boggles. So i start to turn the pilot screws out from 3 turns up to 7 turns out. Only when i get them at 7 turns out, when i blip the throttle it doesn't boggle anymore.
As far as i know, when you turn the pilot screw out, you make the fuel mixture richer, and if you drop the floats height you also make the fuel mixture richer at low RPM.
What is the cause of this oddly high number of turns out of the pilot screws?
Because as far as I know, if the carbs ar worn, the fuel mixture is richer. So if my carbs would be worn I would not have to make the fuel mixture richer by turning out the pilot screws.
Help me out because I'm completely lost!
Thanks guys!
P.S. I forgot to mention that the clip on the needles is at the last position toward the thick end of it.

The stock position for the clip on the needle is the second position from the top of the needle, with your float height of 24 mm and your clip position your running very lean (the lower the clip position on the needle = rich). stock float height is 22mm with a float height of 24mm = less fuel in the bowls & very lean. Have you removed the pilot air jets in the mouth of the carb, and cleared those jets & the passageway? also clear the main air jet again in the mouth of the carb.

dropping the float height to 24mm actually = less fuel in the bowls = leaner not richer, you don't say if you have a jet kit, nor if your emulsion tubes are warn.

try a search im sure this has been covered in the past

good luck.

CJD,
everything is clean and clear. i cleaned the carbs inside out. i don't have a jet kit installed. the emulsion tubes don't seem to have the oval shape as described on factorypro site.
I just don't understand why it takes so many turns out to compensate for that boggle when i blip the throttle.

UPDATE:
Just got back from the garage. The bike revs great, but with these settings:
22 mm float height
2-nd clip position from the top on the needles
pilot screws 6 turns out


Still to many turns out, and I still don't know why.

the needle setting will have NO effect on tickover. How are you setting the float heights?? I know when Flipper does float heights on the Exup, he takes carbs off, tips them upsidedown, and measures height of bottom (top now??) of float to body of carb. He sets them at around 14mm.

We cant see that there would be such a difference between the same type of carbs on similar machines

Ice Queen wrote:the needle setting will have NO effect on tickover. How are you setting the float heights?? I know when Flipper does float heights on the Exup, he takes carbs off, tips them upsidedown, and measures height of bottom (top now??) of float to body of carb. He sets them at around 14mm.

We cant see that there would be such a difference between the same type of carbs on similar machines

The 14mm setting is really for the EXUP 1ks. 600 is closer to 23-24mm. Nonetheless the needle position doesn't really come into play until the midrange. If you're still bogging out then you probably still have a rich condition happening. I've you've you synched and cleaned then you may want to look at you jet sizes and, possibly, go down.

Ice Queen,
As sweekster said, 14mm is the floats height for the fzr 1000; for the 600 is 22 mm stock. I apply a similar method as Flipper does. I tilt them at 45" and let the little metal plate seat on the needle valve without compressing the spring.

I know that the needle position does't come to play untill midrange,but i wanted to start with the stock settings. I had 110 main jets on it, but i took them off and reistalled the stock 107.5 ones before i started the tune up.
The carbs are all stock, the air filter is stock (washable - don't know if it's K&N), the floats height is 22, idle screws are 6 turns out, and jet needle is set at 2 clip from top (stock position). I took it for a ride with these setting and it has a smooth powerband and doesn't back fire and things like that; it sounds and drives very nice with these setting, but that high number of turns out keeps messing with my mind.
If i try to start the bike with the floats at 22m , and idle screws 3 turns out, it doesn't start. I have to turn the idle screws to at least 4 turns out. After i start it, when i blip the throttle, it boggles and only after it boggles it revs up, and when it's coming back to idle is coming very slow. As far as I know that a lean condition, so i continue to turn the idle screws out until 6 turns out. When I reach 6 turns out it revs fine without boggling and it come very easy back to idle.
Should I try to lower the floats height even more than 22, because that will make the idle mixture richer?

trifgeorge wrote:I tilt them at 45" and let the little metal plate seat on the needle valve without compressing the spring.

That may be your problem, as far as I know, you invert (turn the carbs upside down) then set the float height, with the spring compressed. Someone correct me if im wrong.

Thats said if shes running fine, don't fix it.

You should "not" compress the springs if setting your fuel level this way, the float bowls should just "seat" onto the fuel needle spring and measure from carb gasket seat to top of float bowl. I use a caliper locked in at my designated measurement, much easier this way. I recently set my float bowls to 15mm as the FZ750 I recently purchased was running way too rich (jet black plugs and hard starting) the floats were originally at 25mm, now the bike runs way, way better, starts right away and the plugs are a nice tan color. (87 FZ750 with K &N dynojet kit and K&N airbox filter with 4:1 Yosh exhaust.) I may still do some fine tuning with the floats but it at a good starting spot now. Keep in mind K&N's instructions are made to "richen" your setting and depending even the altitude where you live it may be too much. Hope this helps.

One checking method I use when set float heights is that I blow through the fuel line and lift the float to the point it starts leaking a bit and record the level and check if all 4 open up at the same height by same pressure. If one is off the line up it means the valve/seat is suspect.
You don't have to blow hard, just enough so you can tell when air leaked. Air leaks much easier than fuel by the way.

If you need 6 turns out on the idle mixture screws to get it to even start, then you have one of two things going on in my opinion,

a) not enough pilot/idle jet (i.e for example you have #30's...you need to step up to 32.5 or 35)

b) like CJD said..you have restriction in the idle AIR bleed passages..these are fed by the idle air jet in the mouth (upstream) side of the carbs. One would think logically that plugging this will RICHEN the mixture, but the way they work is that the idle bleed air helps provides the vacuum that pulls fuel through the pilot jet. Check these thoroughly.

also, guess I should have said three things.....


How are your valve lash clearances? Without good intake valve seal, starting is tough, starting on a lean mix is impossible, and almost no carb tuning work well as the carbs are entirely dependent on intake vacuum to make them meter fuel and air properly.

did you figure it out? having the same problem here.