Carb quirks

billruiz · Post by **billruiz** » Sat Jul 19, 2008 11:20 am

After getting all my parts and sh*t together I finally attacked my carbs. I've installed new FP emulsion tubes along with the Config 10 jet kit. I got replacement slides that were not Dynojet drilled. So after following all the baseline settings, it still feels a bit flat from idle to 2-3K. I have no "idle" hang ups or drops. It returns to idle after blipping. The jet kit came with two 127.5 and two 130 main jets. I tried those and it was all I could do to hang on when I tried the 7.5K to redline test...the cop wasn't impressed since there have been a rash of kids wrecking their bikes, but let me off when I explained what I was doing. I even showed him the test procedure from FP. I also used the new pilot jets that came with the kit. Anyway, I'm not getting any stumbling or hesitation. It just doesn't feel smooth. I've got a feeling the mains might still be a bit rich, but the 122.5/125 combo didn't pull quite as hard. I've tried the fuel level at both 14mm and 13mm. 13 seems smoother, but no idle hangups or drops when blipped. One other quirk. I stopped to pick something up during my road test. I was in the store maybe 20-30 minutes. When I went to start the bike I could hear the fuel pump run for more than a few seconds, almost as if the bowls had drained. Instead of lighting right up she kinda coughed to life then seemed to need a few seconds to clear her throat. Any advice?

Post by **FZRDude** » Sat Jul 19, 2008 11:43 am

bill wrote:...it was all I could do to hang on when I tried the 7.5K to redline test...the cop wasn't impressed...

:ha and in what gear did you do the "test" that the UFO wasn't impressed with? Did you offer to do it in a different gear so that he might be impressed?

bill wrote:...I've tried the fuel level at both 14mm and 13mm...

Sorry Bill, I don't recall which bike you have. The FZR1000 has a 14 mm Float Height and the YZF750 has 15mm Float Height. Float and Fuel Heights are different measurements.

sickle44 · Post by **sickle44** » Sat Jul 19, 2008 12:10 pm

Have you replaced your float valves?
When was the last time you synced the carbs?
Where are your pilot screws?
Stick with the 122.5's and the 125's the 27/30 combo is as you expected too rich.

billruiz · Post by **billruiz** » Sat Jul 19, 2008 12:14 pm

I was in 2nd gear

I think he might have had a bike, although I was ticketed by a CHP bike cop while trailering my R6 a few years ago.

I have a 94 FZR 1000. I should've said float height. Before I forget, which part of the float do you measure? The float has two pontoon-looking things, but seem to be different sizes.

Post by **FZRDude** » Sat Jul 19, 2008 12:38 pm

billruiz wrote:...I was ticketed by a CHP bike cop while trailering my R6 a few years ago...

That's because you weren't riding it...

billruiz · Post by **billruiz** » Sat Jul 19, 2008 1:55 pm

I have replaced all the gaskets and float valves in addition to the tubes and jet kit. My bike was Dynojetted years ago so that's why I had to find original spec slides. I've since lost the original Mikuni jets, so I guess I better get those. Air mixture screws at 3 turns out.

billruiz · Post by **billruiz** » Sat Jul 19, 2008 2:01 pm

Good news. The guy I "borrowed" the 122.5/125's from said I can keep them, but they don't pull as hard as the 127.5/130's/. I wonder if I go with 125/127.5 if that would work...damn, I hate working on my bike

goingtoscotland · Post by **goingtoscotland** » Sat Jul 19, 2008 5:23 pm

might try 2.5 turns out on the pilot air screws.

billruiz · Post by **billruiz** » Thu Jul 24, 2008 7:18 pm

Success!!!

After finally getting the float height set THE SAME for all (14mm), I went back to the 127.5/130 combo, needle in the 3rd position, screws out 3.75 turns. Everything is nice and smooth, no hiccups, backfires, stumbles, hesitation. It's probably running rich, but hell, this is the best it has run in years. I'm hoping the fuel mileage is better than the dismal 25mpg I've been experiencing...now I just gotta get the suspension going.

goingtoscotland · Post by **goingtoscotland** » Thu Jul 24, 2008 9:17 pm

billruiz wrote:I'm hoping the fuel mileage is better than the dismal 25mpg I've been experiencing...now I just gotta get the suspension going.

mine was almost as bad as yours was. i was getting 26 mpg city, 31hwy. messed with the air screws, new plugs, and i get 37 hwy now(my speedo is broken so i had to remember how much i put in and google mapped the route i took for the mileage. still unsure of city mpg. hopefully when i get my speedo fixed i'll find out.

billruiz · Post by **billruiz** » Thu Jul 24, 2008 10:07 pm

Maybe I should've replaced the plugs as well

I've got a new petcock assembly arriving any day now. I'll get to the plugs while I've got the tank off. BTW, I've got these two white "tees" which I assume are for carb venting or overflow. They look like they accept a hose. Does anyone know how long those hoses should be? Or will they be okay "hoseless"?

dragracer1951 · Post by **dragracer1951** » Fri Jul 25, 2008 9:09 am

3 1/2 turns out it huge.
Turn them in a turn.
I'm betting you are rich on the needles also.

billruiz · Post by **billruiz** » Sun Jul 27, 2008 5:41 am

On my ride out to the Duc dealer I was able to find some smooth country roads to test my FZR. I think I'm pretty close to the main jet size. I don't think I've ever felt that kind of power since I've owned it. The idle and low speed operation is better, but I'll turn the screws in and go back to the #2 position on the needles.

creed12r · Post by **creed12r** » Sun Jul 27, 2008 10:05 am

billruiz wrote:Maybe I should've replaced the plugs as well I've got a new petcock assembly arriving any day now. I'll get to the plugs while I've got the tank off. BTW, I've got these two white "tees" which I assume are for carb venting or overflow. They look like they accept a hose. Does anyone know how long those hoses should be? Or will they be okay "hoseless"?

You're OK to run without the overflow hoses

Chris

dragracer1951 · Post by **dragracer1951** » Mon Jul 28, 2008 3:24 pm

Word...
You wouldn't think them little tubes could generate that much vacuum to make the bike run rich but they do...

billruiz · Post by **billruiz** » Mon Jul 28, 2008 4:34 pm

I went back to 2.5 turns on the screws and #2 pos on the needles...not so good. The idle hangs when blipped and off idle to about 3k surges more than the 3.75 turns/#3 pos setting. The 7K to redline test is still pretty good. I was able to haul in some kid on his new CBR 600RR. He asked, "What's FZR?" I answered, "pre R1." He snickered and said something about old bikes then proceeded to rev his bike like a moron. I revved it a bit just to get him going. (Disclaimer. I do NOT condone street racing...) When the light turned green I eased it out while he dropped the hammer. When he got about five bike lengths, I gave it the hammer and reeled his tank-top, shorts wearin ass in. I remember hitting the rev limiter twice then easing off the gas. I saw the kid in my mirror, then he flew by still hard on the gas.......so yeah, it pulls pretty good to redline

So I'm gonna go back to #3 on the needles and tweak on the screws. I've checked for vacuum leaks and such just to rule those out. The only other thing I haven't done is a valve adjustment. 37K miles. The only time I took off the cover was to paint it gold about 8 years ago.

dragracer1951 · Post by **dragracer1951** » Mon Jul 28, 2008 6:42 pm

Bill,
Let me 'splain this to you.
The bike needs to be tuned from Idle up. I know everyone will tell you that ain't the way to do it but humor me for a bit.
The main ain't got shit to do with the bottom. In fact it will start and idle just fine if you take out the main jets.
They don't do diddley.
No kiddin.
get it to idle nicely. Adjust your valves for Gawd sakes....
That will have a lot to do with carb sync. Think cam overlap, manifold pressure and vacuum carbs and the light will turn on...
sync the carbs to get it to idle at the lowest it will and then use the pilot air screws to gain rpn one cyl at a time lowering the idle adjuster to the lowest it will run for each cylinder. By lowest I mean sub 500 rpm.
Then adjust the needle to the third or fourth from the top and do plug chops. when it starts to go lean, you will notice it won't answer the call for power. That's one step too fookin lean.
Swap mains from richest to leaner. Same thing applies, when it's too lean, it won't answer the call for power.
Anything else and you're just guessing.
Don't get sucked into equating throttle position with slide and thus needle position. The two ain't connected.

EXUP Worldwide

Carb quirks

Carb quirks

Re: Carb quirks

hoses