I drove my bike today. Runs rough 1/8 throttle. Right now, I have a .19mm (.020") washer under the clip on needles. Float level is 21.8mm (.86").
Starts and comes off the choke good.
Cold -runs good off choke
warm-Runs rough 1/8 throttle but crank a little more and it comes out of it.
Idles ok- light blip drops below 1000 and then rises back up.
I still got the 37.5 fuel jet
I adjusted the mixture screws from 3 to 3 1/2 turns with no change
I have uni-pod and the F1 cans
I guess whats confusing me is the "CV carb jetting.pdf 4d" states that this is a rich condition. "light blip drops below 1000 and then rises back up".
I had the mixture screws at 2 and 2 1/2 before and it was rough blipping and popping from the carbs
but I can't remember if it was before I adjusted the floats.
Should I put the 40. fuel jet? Wouldn't that would make it richer?
How can I fix this cheap as possible
It is my understanding that in doing the blip test if the rpm drops below 1150 (or where ever your idle is set, I would adjust to 1150) then rises it is a to lean condition.
Under the assumption that the carbs are synced good I would pull those fuel jets and fuel air screws and clean the system at a minimum. Be careful with the fuel air screws, there is a washer and small o ring there on each screw.
I wouldn't think your needles are much of a player at 1/8 throttle. Others can chime in with more experience. As far as changing the 37.5 fuel jets, call or PM Randy and install what ever he recommends.
George
Thats what I was thinking, George. My setup should be in a lean state but this;
"C. If the throttle is lightly "blipped" at idle, and the rpm drops below
the set idle speed, then rises up to the set idle speed, the low speed
mixture screws are probably set too rich: try 1/2 turn in, to lean the idle
mixture."
doesn't seem logical. It should be lean with the 37.5's.
Might help to read this file.
http://www.fjowners.com/index.php?topic=655.0 (http://www.fjowners.com/index.php?topic=655.0)
I am not carb expert. I just try to comprehend as much as I can. And I attend the school hard knocks and "aw shit" (I have a masters in that) .. But it is my understanding that if you do the blip test and the RPM returns rapidly and go's below the set idle rpm then returns to the set level you are to lean.
If the rpm returns slowly and settles at the set rpm level then it is to rich.
You should be able to induce both problems via the fuel air screws so you know what you are looking at. If you can't then something is plugged or out of adjustment.
If the fuel air screw is turned in on an FJ then you should be leaning the idle. Turning the screw out should be enriching the idle.
George
Quote from: Joe Sull on March 18, 2014, 06:45:10 PM
doesn't seem logical. It should be lean with the 37.5's.
The 37.5 jets are just for idle, once you get on the throttle you are off the idle jets. So switching to #40 should not have any real effect on your 1/8 throttle position. And I found #40 to be a smoother less finicky idle on my FJ.
....and #40's are easier to keep clean. It seems that the pilots are first to plug up with our crap E10 gas here in Kalif...
To answer Joe's question, I would also check the needle jets (aka emulsion tubes) to make sure all the little holes are open. Especially the bottom holes (closest to the main jets)
I disagree with Mark. When I installed the #40 pilots, I noticed immediate improvement from idle to approx 1/2 to 2/3 throttle. Better response, smoother operation and no real mileage penalty to boot. It ran soooo much better I would have given up 5 mpg and still been happy.
Yes Ed, you are correct. I think Mark got confused with the air idle circuit.
The pilot jets do effect the low speed characteristics.
Ok, I'll pull out the emulsion tubes and check them and I'll replace the pilot jets with #40's. Thanks for the replies and the advise.
I still don't understand why the blip test implies a rich idle state.
As you state it your blip test indicates to me you are lean. "Idles ok- light blip drops below 1000 and then rises back up." ?
Here is another link to read.
http://www.fj1200.info/mixture_screws.htm (http://www.fj1200.info/mixture_screws.htm)
George
Pilot jets alter the same region that the mix screws tend to, it's noticable at steady-state cruise, low speeds, long gears (4th at 35mph say).
Start with fresh gas, and possibly check the synch, if it's a recent problem. If it's always been this way, do those and then look at the brass.
Quote from: movenon on March 19, 2014, 07:15:38 AM
As you state it your blip test indicates to me you are lean. "Idles ok- light blip drops below 1000 and then rises back up." ?
Here is another link to read.
http://www.fj1200.info/mixture_screws.htm (http://www.fj1200.info/mixture_screws.htm)
George
Which makes more sense.
That opposite what these two doc. are saying,
http://www.fjowners.com/index.php?action=dlattach;topic=580.0;attach=255 (http://www.fjowners.com/index.php?action=dlattach;topic=580.0;attach=255)
http://www.factorypro.com/tech_tuning_procedures/tuning_carbtune,CV,high_rpm_engines.html (http://www.factorypro.com/tech_tuning_procedures/tuning_carbtune,CV,high_rpm_engines.html)
If I recall correctly, the manual lists #40 jets in Europe and #37.5 jets in the US. I assuming for the 37.5's were put in to meet emission standards in the US. I interpret that to say that Yamaha preferred the bike to run on #40's, and stuck 37.5's in to pass US standards. I put the 40's in mine.
Quote from: andyb on March 19, 2014, 08:18:40 AM
Pilot jets alter the same region that the mix screws tend to, it's noticable at steady-state cruise, low speeds, long gears (4th at 35mph say).
Start with fresh gas, and possibly check the synch, if it's a recent problem. If it's always been this way, do those and then look at the brass.
Andy, The carbs are cleaned and sync'd and I have fresh gas.
"it's noticable at steady-state cruise, low speeds, long gears (4th at 35mph say)."
Thats exactlly were the problem was.
Ok, I took the carbs apart and checked how clean the jets were and it's all good except for something I overlooked.
(http://i1212.photobucket.com/albums/cc460/whiterabbit30/bs36-001.jpg)
There was a tutorial Andy made that mensions these two holes up the top of the throat.
I never did clean these out. I can't find the tutorial again so how do I get them clean without rounding a corner off
or getting something stuck.
Joe, here's the q-d way to get those passages cleared out. Remove mixture screws @ air filters. Spray carb cleaner through the mixture screw hole until you see it Cingular out the air jet at the carb mouth. Next cover the air jet with a finger and spray again, which will force the carb cleaner through the passage near the throttle butterfly. Reassemble & test.
2 warnings:
1.) carb cleaner may/will spray everywhere including all over your nice red paint AND into your face.
2.) record the position of mixture screws as you remove 'em & don't mix them between carbs.
Good luck!
Sorry iPod keyboard malfunctioned ...
Quote from: simi_ed on March 19, 2014, 08:02:16 PM
Joe, here's the q & d way to get those passages cleared out. Remove mixture screws & air filters. Force spray tube into passage until semi-seals to force cleaner through passage. Spray carb cleaner through the mixture screw hole until you see it squirt out the air jet at the carb mouth. Next cover the air jet with a finger and spray again, which will force the carb cleaner through the passage near the throttle butterfly. Reassemble & test.
2 warnings:
1.) carb cleaner may/will spray everywhere including all over your nice red paint AND into your face.
2.) record the position of mixture screws as you remove 'em & don't mix them between carbs.
Good luck!
Ed, I got some carb cleaner and shot thru those ports. The holes directly below the needles were all open but the forward ones were not. The #1 & 2 were partially blocked and the #3 & 4 blocked but the carb cleaner made quick work of it. I shot each from the needle hole and by the time I went back over them, they were clear. Thanks for the tip. :hi: