FZRSupport: the FZROnline Archive

Ok so i finally got my bike running after doing some carb work. while i was in there i noticed the bike had a dynojet kit but the jets that were in it were 108's which are smaller than stock. The only thing the bike has is a full exhaust system. I synced all the carbs together but i still cant get the bike to idle for shit. I got it to where it like barely idles then i rev it a hair and it revs to like 6k and will sit at about 4k. Its rediculous. i dont want to be on the gas all the time. What should i do. I was thinking a lot of you have jet kits and have extra jets laying around, so i was just wondering if i could borrow some jets to see if i can fix it.

Its really making me mad, i was thinking maybe it could be something else like something electrical like the VR or something. If any of you have any other ideas that would be helpful.

Thanks guys,
Dan

FizzNation wrote:Ok so i finally got my bike running after doing some carb work. while i was in there i noticed the bike had a dynojet kit but the jets that were in it were 108's which are smaller than stock. The only thing the bike has is a full exhaust system. I synced all the carbs together but i still cant get the bike to idle for shit. I got it to where it like barely idles then i rev it a hair and it revs to like 6k and will sit at about 4k. Its rediculous. i dont want to be on the gas all the time. What should i do. I was thinking a lot of you have jet kits and have extra jets laying around, so i was just wondering if i could borrow some jets to see if i can fix it.

Its really making me mad, i was thinking maybe it could be something else like something electrical like the VR or something. If any of you have any other ideas that would be helpful.

Thanks guys,
Dan

DAM,
You are looking in the wrong place ie main jet. the idle circuit has its own jets and that is where you should be looking.

Take alook for Mikuni CV carb manual on the web (sorry I do not have it b/marked)

do the idle jets get bad or something... Is that why i cant get it to idle right.

After you sync the carbs you need to re-set your idle speed. I did mine and had the exact same problem.

Get the bike warmed up first, then turn the idle adjust nob until it's where you like it. Blip the throttle with each adjustment and see what the revs drop to.

I think your A/F mixture isn't set right. You will have problems with the bike running right, if they are not. Welcome to the wonderful world of carb tuning. I hope you get it sorted out.

how do i fix the Fuel/Air issue. I tried to get all the idle air screws to 3 turns out

Check out Factory Pro's website on the info. about tuning carbs, it's a long process of tuning, so I would have you start there. 3 turns out is just a base setting, from there you need to see if the carbs are running lean or to rich. Can't remember off the top of my head, but I think the hanging of the rpm means your rich or visa versa.

I have always adjusted my carbs via an INFRARED TEMP GUN. The object isn't necessarily a target temperature at a certain idle, but rather each header should be at the same temp.

1. Have your tank on a stool next to your bike so you can adjust the carb IMS (Idle Mixture Screws - see photo below)
2. Let your bike warm up for a couple minutes in an area where there is little wind, but enough ventilation that you won't kill yourself. Doing it in the garage is fine as long as the door is open.
3. Point the gun at each header in the same location when taking temps. Usually 2" out away from the cylinder head is fine.
4. Record the temps on a sheet of paper. Make columns for each cylinder and each temp for each round of adjusting. You will forget - so WRITE IT DOWN!
5. Adjust the IMS screws one at a time and recheck the temps for all of the cylinders. The temps will be change pretty quick, but give them a minute or so to level out. Continue until all of them until they match.

Now, if your idle begins to drop, simply adjust your main IDLE screw that simply opens the throttle a bit to each carb.

After I did this, I wanted my bike to "richen" my bike up at idle for easier starts, so I adjusted each IMS screw to reduce the temps across the board at a given RPM.

Hope that helps!

darrin

wherte is the idle main screw

FizzNation wrote:wherte is the idle main screw

In the pic above, the black hose on the bottom of the carbs with the knob on it.

And just for reference, those are FZR600 EXUP carbs (Cali model). That's why you see the tubes coming out by the bottom of the float chambers on the right side. I do believe they were tied to the vapor canister that would recycle the vapor back through the carbs when the bike was started.