FZRSupport: the FZROnline Archive

So, I have been having the same problem since I got the bike and I can't figure out what the problem is. Here are the symptoms:

When I start the bike, I have to have the enriching lever all the way out.

When it DOES start, the bike revs and idles at about 5K.

When I put the enriching lever back in, it drops the idle off quickly and eventually dies.

When I try to hold the throttle back as I put the enriching lever back in there is a "lag" before it revs up. If I don't hold it open almost all the way, it dies. Holding it open almost all the way only revs the bike to about 5K.

The bike leaks gas from either the carbs or the fuel petcock (a NEW symptom, I am pretty sure it is my fault, but if it IS connected, there it is.)


Here is what I have tried:

I made sure the carbs are clean.

I adjusted the float height to EXACTLY 22mm (it is all stock.)

The idle screws are 3 FULL turns out.

I bench synched the carbs the best I possibly could.

I made sure that there are no air leaks from the boots that go from the carbs to the engine.

New spark plugs (NGKs, the one with the 8 in it. You know the one.)

New gas.

New oil (proper weight and it is motorcycle specific oil. I don't remember the weight off the top of my head, but I double checked before I changed it.)

New oil filter.

Checked the air filter (it looks pretty dang new.)


So there you have it. I am more than a little frustrated. What could this POSSIBLY be? ANY suggestions could be welcome.

Let it be known that when it is running with the enriching lever in, it runs strong and loud.

THANKS in advance. I really am out of my mind with frustration!

I have no idea what the cause of this is but your not alone. I have had my bike for almost 2 years now and its been doing this ever since i got it. It's pretty annoying but if you start it a minute or two before you take off and let it rev with choke all the way out it will begin to run smoothly so you can turn the choke off. At least thats how mine is. Does that sound like yours? If you've been riding and the bike is only stopped for a few minutes does it start up pretty smoothly? Hope somebody has an answer to this problem.

Guys,
Ok Fzr's are very sensitive to the cold (even on a hot day) I start the bike on full choke then sort my self out jacket , helmet, gloves visor.
On starting with full choke the revs to 3K+ I use the choke lever in a bit get the revs at about 2K then ride off. I will watch the temp guage to get it off zero and the bike is working well then shut the choke entirely whilst riding.

If I shut the engine off at my destination the above will still hold true but just a shorter time

If this does not work for you then

1} the lower rev range jets are dirty (yeh you may think you cleaned them ) use a NYLON fish wire not metal to pass thro each jet.

2} bench synching is a start

3)Dynamic synching with sych tool is the only real setup

4) Use the WIKI to research the synch tool most here use

yamaha_george wrote: 3)Dynamic synching with sych tool is the only real setup

4) Use the WIKI to research the synch tool most here use

Bench synching, from my experience, will not even get you in the ball park. Dynamic, as George put it, is pretty much the only way to go when it comes to any type of synch process. The downside is it will take more time to get it right. The upside is the result of a great running bike.

.
Dynamic sync is the ONLY way to go.

FWIW tho check that your valveclearances at least aint completely out of whack.

Then,on warm engine,there´s absolutely nothing that states that the idle mixture screws need to be turned 3 turns out.
It´s been my experience from time to another that albeit the most analy cleaned carbs in the world sometimes there ever so minute residues left that can easily havoc the extremely small holes of the light load circuit.
In short,run the engine and adjust the idle mixture screw for highest idle first.
THEN adjust until idle drops(for hot engine),and in this scenario a tach is a very usable tool.(no...NOT the one on the bike.It lacks resolution for this kind of work)
By how much...here´s where feel comes into play.

THEN adjust syncronization,cause there´s absolutely no way in hell that you´re going to get a smooth running engine if one or several cylinders are running out of whack from a fuel POW.

MC206 wrote:So, I have been having the same problem since I got the bike and I can't figure out what the problem is. Here are the symptoms:

When I start the bike, I have to have the enriching lever all the way out.

When it DOES start, the bike revs and idles at about 5K.

When I put the enriching lever back in, it drops the idle off quickly and eventually dies.

When I try to hold the throttle back as I put the enriching lever back in there is a "lag" before it revs up. If I don't hold it open almost all the way, it dies. Holding it open almost all the way only revs the bike to about 5K.

The bike leaks gas from either the carbs or the fuel petcock (a NEW symptom, I am pretty sure it is my fault, but if it IS connected, there it is.)


Here is what I have tried:

I made sure the carbs are clean.

I adjusted the float height to EXACTLY 22mm (it is all stock.)

The idle screws are 3 FULL turns out.

I bench synched the carbs the best I possibly could.

I made sure that there are no air leaks from the boots that go from the carbs to the engine.

New spark plugs (NGKs, the one with the 8 in it. You know the one.)

New gas.

New oil (proper weight and it is motorcycle specific oil. I don't remember the weight off the top of my head, but I double checked before I changed it.)

New oil filter.

Checked the air filter (it looks pretty dang new.)


So there you have it. I am more than a little frustrated. What could this POSSIBLY be? ANY suggestions could be welcome.

Let it be known that when it is running with the enriching lever in, it runs strong and loud.

THANKS in advance. I really am out of my mind with frustration!

I see no mention about messing with the idle screw..So try turning it in(tighten) and see if it helps. Also try turning your idle screws to 4 turns out. It seems that your bike is not getting enough fuel or it is lean. If it still doens't work then take the carbs apart again ,replace all the gaskets,pull all of the jets out and clean them with air and carb cleaner. Same thing for all of the small passages. Mine did not idle right because one of the pilot air screws was really plugged.. I know it is frustrating but you have to get used to pulling the carbs out and synchronizing them every time. I pulled mine out last night , changed the emulsion tubes ,all gaskets,float valves ,and synched them in about 1 hour. Now it idles dead on where I set it and runs really strong without hessitation.
Good luck

Several things have been pointed out which are very good, but in reality your circuit is too "lean" at start-up and that is where the IMS (Idle Mixture Screws) come into play.

In order to effectively manage your IMS settings, you will need an Infrared Temperature Gun to check header temps (take temp at the same spot on each header). I would lower the temps by 30 degrees and try it. Keep all of the header temps as even as possible.

I'm with these guys on the "Dynamic" carb sync. A bench sync can get you close to start.

My bike fired up without the choke every time... which was not necessarily good either.

darrin

I'm saying that even though the carbs have been "cleaned", they AINT.


To do it right means pulling ALL brass and rubber out of the bodies, having compressed air (and using it) and plenty of effective carb cleaner on hand.

Air passages often get neglected/overlooked-they are often VERY small and always critical. The idle mixture circuit cannot work properly without the idle bleed air jets/passages clean.

Strip them all the way (again?) and CLEAN everything. Use carb cleaner and then compressed air. Go backwards (upstream) first, then downstream. During the carb cleaner cycle, visually verify that spray is coming out the other end of the passage you are working on.

bench synch them with the butt of a small drill bit (.030" will get you running) and install them-and see what it does.