• Welcome to the Yamaha FZ1 Forums. Member registration disables ads and allows you to post and share. Register Here.

Carb Adjusting

Isleoman said:
Good news!

It would be interesting to see where the plates are now after using the gauges. I’ll understand if you’ve had enough carb pulling. It does get faster with each time you do it.
Click to expand...
Started the bike again today. used a little choke to get it running. Doesn't hold idle well again & throttle up stalls it. Sticks don't register any vacuum until I open the throttle a little bit & with that little bit of choke, it revs up quick & I have to control the idle with the choke. Still not fully synced so I'll try to get that right 1st. This makes me think there's a vacuum leak somewhere. Both side of the carbs are tight; head & airbox boots, at least from what I see. Try to get all 4 carbs synced & bike to idle then I'll spray some carb cleaner around the intake boots to see if that effects the running.

If I can't get it to run correctly from this, I'll pull the carbs again & check those plates When it throttles up & I get vacuum readings, only #2 carbs is higher than the others, the rest are pretty close to each other. And I've checked that the hoses for the sticks are tight on each boot nipple, so I don't think that's the problem.

Stay tuned......
 
After all the work you've done it's hard to imagine how it could be but needing the choke at idle seems like there's still a fuel delivery problem in the idle circuit.

The problem with cracking open the throttle and it dying is now solved right?
 
jwarden said:
After all the work you've done it's hard to imagine how it could be but needing the choke at idle seems like there's still a fuel delivery problem in the idle circuit.

The problem with cracking open the throttle and it dying is now solved right?
Click to expand...
Not really. When I 1st put that carbs back in after cleaning, it ran Ok & would allow throttle. Today, it's back to where it won't allow any throttle. The only thing that changed the rpm's was the choke; started off with about 1/3 choke to get it started & when it wouldn't idle without ch9oke, I went to the idle speed adjusting screw, turned that up a little but as soon as I tried to open the throttle a little, it would rev to 3k+ & I'd have to cut the choke altogether to lower the revs & then the engine would die. Hit the idle screw a bit more after next start & tried to let it warm up a bit to see if what was the issue, but didn't have time. (Damn haircut girl only works on Sundays!!) So onto a more thorough test tomorrow.

My big question of the day is, why does my Carbtune sync tool not show any vacuum @ 1k rpms? It should be showing something. That's the 1st thing I'm gonna check tomorrow is get the bike started & idling & spray the intakes to see if there's any leaks there that aren't letting it breath correctly, then move on from there.

Another thought is if this slip on exhaust canister is making a difference in what the carbs need to run correctly? All stock jets with an unknown slip on.

Check back in tomorrow with hopefully some good news!
 
roguevfz1 said:
Not really. When I 1st put that carbs back in after cleaning, it ran Ok & would allow throttle. Today, it's back to where it won't allow any throttle. The only thing that changed the rpm's was the choke; started off with about 1/3 choke to get it started & when it wouldn't idle without ch9oke, I went to the idle speed adjusting screw, turned that up a little but as soon as I tried to open the throttle a little, it would rev to 3k+ & I'd have to cut the choke altogether to lower the revs & then the engine would die. Hit the idle screw a bit more after next start & tried to let it warm up a bit to see if what was the issue, but didn't have time. (Damn haircut girl only works on Sundays!!) So onto a more thorough test tomorrow.

My big question of the day is, why does my Carbtune sync tool not show any vacuum @ 1k rpms? It should be showing something. That's the 1st thing I'm gonna check tomorrow is get the bike started & idling & spray the intakes to see if there's any leaks there that aren't letting it breath correctly, then move on from there.

Another thought is if this slip on exhaust canister is making a difference in what the carbs need to run correctly? All stock jets with an unknown slip on.

Check back in tomorrow with hopefully some good news!
Click to expand...
Don't think the slip on will affect jetting enough so that it won't run.
 
How much vacuum should the sticks be reading @ 1k rpms? It should up near 20-24, right? If I'm not getting anything until I blip the throttle, what does that tell us? There's gotta be some kind of leak or hole in the system somewhere, right?

Those tiny o rings that go in the carb tops; 1 side is a hole in the cab top & the other side is the body of the carb with no hole. What do those o rings actually do? I replaced 2 of them by finding the nearest size to them I could. The new 1's look slightly thicker but when I screwed the tops down the plastic lid looks completely level with the carb bod & no gap where the o rings are. Could that be a leak there, even if it looks good?
 
I remember in the FZ1Oa Raven Rider carb mod write up that it was indicated that those small o-rings under the carb tops are not even really required. I use them but that was the claim. I agree with Killer that slip shouldn’t make any difference.

What was the condition of the bike before you started cleaning?

http://www.cartestsoftware.com/fz1/carburetorsynchronization.html.

Pat gives the pressure as [The specification for vacuum pressure at idling speed is 22.5 cm, 225 mm, 30 kPa, 8.86 in. of Hg.]
 
www.simplymotorcycle.com

14 Reasons ‌Your Motorcycle Dies When Given Throttle

Motorcycle engines are relatively simple. You add fuel, ignite it, and the engine generates power. Add more fuel, and the engine gives more power.
www.simplymotorcycle.com www.simplymotorcycle.com

Item 10 in article (blocked gas cap vent ) was something I was going to ask about, can you try running it with the gas cap open, may have to fool around with it a little to get key out of cap to start bike.
 
Isleoman said:
I remember in the FZ1Oa Raven Rider carb mod write up that it was indicated that those small o-rings under the carb tops are not even really required. I use them but that was the claim. I agree with Killer that slip shouldn’t make any difference.

What was the condition of the bike before you started cleaning?

http://www.cartestsoftware.com/fz1/carburetorsynchronization.html.

Pat gives the pressure as [The specification for vacuum pressure at idling speed is 22.5 cm, 225 mm, 30 kPa, 8.86 in. of Hg.]
Click to expand...
The bike ran but it was rough. It took a while to warm up enough to get it to run smoothly & idle well without choke & acceleration was choppy even after warmed up. Rode it twice; once on the test drive & once before starting to work on the carbs after I got it home. The fuel has been in there for about 6 months. The tow company filled the tank right before I came to get it.

That's what I mean; to have zero vacuum pressure @ 1k leads me to believe that this may also be an intake leak issue.
 
Isleoman said:
www.simplymotorcycle.com

14 Reasons ‌Your Motorcycle Dies When Given Throttle

Motorcycle engines are relatively simple. You add fuel, ignite it, and the engine generates power. Add more fuel, and the engine gives more power.
www.simplymotorcycle.com www.simplymotorcycle.com

Item 10 in article (blocked gas cap vent ) was something I was going to ask about, can you try running it with the gas cap open, may have to fool around with it a little to get key out of cap to start bike.
Click to expand...
I have 2 keys for it.

I opened the gas cap & started it. 3 1/2 turns out was what I set the mixture screws at. It starts but still won't accept any throttle & still no reading in vacuum pressure until 2500 or so. Then it only goes up to about 14-16. 1=2 carbs show hi & 3-4 show low but both sets are about even when it registers as it revs. Smells pretty rich too & get some pops in the exhaust. If any choke is on & I twist the throttle, it'll rev up to 3k+ & I have to let all the choke out to lower it back down & with no choke if I twist the throttle just a little, it stalls. Also, the fan comes on after about 45 seconds of running. Not even close to hot.

Another thing I noticed is that carb 4 has a hose that leads to what I believe to be the EXUP valve under the tank that then has steel lines leading to the head just above the exhaust pipes. I have that blocked off with a screw while tuning. Could that have anything to do with any of these issues?
 
Last edited:
TPS was also loose. Set it the where I think the marks had it set before. Started it again, set the idle screw to where it idled @ 2k so I could get readings & set the sync screws to where they're all pretty close. 2=3 are a little higher than 1-4 but she's accepting some throttle now. Still, when I lower the idle to 1k I get no vacuum readings. I'll keep fidgeting with these settings & see where it leads.
 
Hey all. Have been dealing with car & truck issues but was moving stuff in the garage around so I started the bike & went to oil it out of the garage & as soon as I put it in gear, it jerked forward & stalled, almost like the clutch wasn’t disengaging the engine from the tranny. What could possibly make that happen? I can see the clutch cable pulling the lever & mechanism on the crankcase; I never touched anything as far as clutch cable or adjusted it; it worked fine before, even when it was running rough & I was trying to tune it.

Is there Gremlins in this bike??
 
The clutch plates may be gummed up and stuck together. I’d throw it on center stand and repeat trying to put it in gear. Then work the clutch lever in the various gears as it turns.

Having suggested gummed up clutch I will say I’ve never experienced it after letting my bike sit all winter.
 
You must log in or register to reply here.
Back
Top