FZR1000 problem with idle/high rpm when warm

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DrGreve
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FZR1000 problem with idle/high rpm when warm

Post by DrGreve »

Hi!

I got a 1993 FZR 1000 with a 1990 engine. This is my first bike and I got my driver license two weeks ago, yay!

I bought the bike in april. It was a pretty good ride except sometimes it lagged in throttle response. Also me and a couple of buddies rode up a steep mountain road and stopped midway to take some pictures. I fired it up to continue driving up the road and when i turned the throttle it died after a short while. I tried several times. When I drove it down the hill it was no problem, so I had to go down in order to gain enough momentum to get all the way up again.

I thought the problems might have been the float settings.

So, as the mechanical novice that I am, I decided to work on it (might have been a mistake :ermm: ). I changed the fuel filter, fuel lines, spark plugs and took off the carbs and cleaned them. I also adjusted the pilot air screws to spec. I adjusted the floats, but I didnt get it right the first time(s) as I wasnt accurate enough and got overflow as a result (also one time some debris clogged the valve to cause overflow).
I got it right after making a 14mm "tool" to adjust them precisely (it was harder than I thought using eye sight :unsure: ). Finally it was good again, after 3-4 times taking the carbs on and off. The Idle was a little low so I adjusted that. Now the throttle response is good, but I dont know if the "steep hill problem" is gone yet. If not, what might be the cause of this if it isnt the carb settings?

Now I got a new problem. When I start the engine (and after applying choke) and it warms up it settles at around 1000 rpm as it should. But after driving for 30 seconds or so it wont go below 2000 rpm, and it rises to almost 2500 rpm when i pull the clutch. The bike has to completely cool down in order for it to idle at 1000 rpms again. My initial thought was that I had an air leak around the carburator boots. So I pulled them off. They looked good. I clamped them on as tightly as a could and put the carbs back on, also as tightly as possible in that end (with the help of grease). The problem persists and it soooo frustrating. It hurts to clunk it in first gear when it revs at 2000 rpms as I had to the other day after rinding to the gas station. Btw I also changed the clutch plates the other day and the gear changes are like butter, when the rpms are normal.

Below are pictures of grooves at the top of the intake. I cant remember them being the before, but they might have been. I can feel the grooves with my fingers, and there are two of these in each intake wall, at the left side for the two left side carburators and on the right side for the two right side carburators. What causes these grooves? Or are they machined in like that?

Image http://tinypic.com/m/ifmt00/4
DrGreve
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Re: FZR1000 problem with idle/high rpm when warm

Post by DrGreve »

I should add that the O-ring for the pilot air screw in the number 4 carburator is missing. It is set at 2.5 turns out like the others. I also "manually" synced the carbs without a manometer, so they are possible not perfectly synced. Could the missing O-ring cause a rich mixture that would disturb the sync of the carbs and cause them all to idle to high? But if this is the case shouldnt the rpms get too high before I ride it?
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Stig
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Re: FZR1000 problem with idle/high rpm when warm

Post by Stig »

if air is getting past the air screw it will make the idle high. BTW, not sure where you are for model numbers but the UK 1990 air screws are 3 turns out
If its not broken it dont need fixing

http://www.exup1000.co.uk
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coops
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Re: FZR1000 problem with idle/high rpm when warm

Post by coops »

The groove in the intake port is normal, machined from new. But can I see carbon down the bottom near the right valve? means the valve is leaking. (don't worry about it)
Dunno about most people but I try to avoid putting grease on rubber. especially carb boots either side. Grease stops the rubber gripping and can squeeze off or blow off.
They have probably shrunk with all the heat over the years. Mine did so I got new ones. Just my 2cents on the rubber.
You may have the carb synk miles out, that would affect idle speed when it warms. Could be a few things or combination of things. Carb tuning can be tricky, even for good mechanics. Good luck.
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