FZRSupport: the FZROnline Archive

A little background, So I was losing all my power at about 6k rpm untill my bike warmed up so I decided to clean and synch the carbs. While I was doing that some metal pices that a previous owner left in the oil pan flew up into the moving parts and I ended up having to take the entire motor apart. The valves were way dirty with carbon so i cleaned everything up real noce and just got it back together. Before my compression was about 90 through all cylinders and now it's 125 in 3 of them and 115 in one. I just finished putting it back together and took if for a spin and I have no power at all. At about 5k rpm it just boggs down really bad and I lose all my power and can't really accelerate at all. Below 5k it will have some power issues but kind of jump back and forth, like it's trying to get up and go but it won't. I just lurches for a sec then loses everything and once I get to 5k it just boggs down and won't go much higher. I've set the valve clearances, synched the carbs and tuned the air mixture screws with an ir thermo. All my headers are about 500*. I've looked at the plugs and the color is good. I don't see that I'm getting any black smoke from the tail pipe but it feels like I'm rnning rich. It's worse if I give it more gas but there's not really any other symptoms of a rich condition. I'm fresh out of ideas. Thanks for the sugestions.

does it accelerate well when it's on neutral and standing still?

Since you recently put it all back together, you need to first make sure that the carbs are seated all the way down and that the tubes connecting them to the intake are tight. Any air coming in through there can have adverse affects.

Is there a Jet Kit on the bike?

i had a similar prob with a gsxr, ended up getting it dyna'd to find the problem and it ended up being a tiny hole in the carb diaphram(had checked before and it was too small to see) causing it to run rich.

could the choke be at fault?

A typical problem on these FZRs are the emulsion tubes. Once they get worn, they create a "rich" situation right in the 6-7k range. A new set of tubes would probably alleviate the situation. If a Jet Kit is installed, then you can simply drop the clip, on the jet needles, a couple notches, which will push the needles into the tubes a little more helping to "lean" it out.

trifgeorge wrote:does it accelerate well when it's on neutral and standing still?

It revs all the way through the rpm range just fine in neutral

ragedigital wrote:Since you recently put it all back together, you need to first make sure that the carbs are seated all the way down and that the tubes connecting them to the intake are tight. Any air coming in through there can have adverse affects.

Is there a Jet Kit on the bike?

I silaconed the carb boots cause there were some small cracks in them and it sealed them up fine. I know they are seated well.
No jet kit

ruddiger wrote:i had a similar prob with a gsxr, ended up getting it dyna'd to find the problem and it ended up being a tiny hole in the carb diaphram(had checked before and it was too small to see) causing it to run rich.

could the choke be at fault?

I don't think its the choke. I do think its a carb problem though. I'll have to check the diaphrams again.

ragedigital wrote:A typical problem on these FZRs are the emulsion tubes. Once they get worn, they create a "rich" situation right in the 6-7k range. A new set of tubes would probably alleviate the situation. If a Jet Kit is installed, then you can simply drop the clip, on the jet needles, a couple notches, which will push the needles into the tubes a little more helping to "lean" it out.

Can you see when the emulsion tubes are worn? I don't have a jet kit now but I've been thinking about getting one cause I'm pretty sure its a carb problem. Everything else is checking out just fine so its really all it could be.

Shocka311 wrote:Can you see when the emulsion tubes are worn?

Most times you can. Sometimes they wear out in a circle and sometimes they wear out in an "egg" shape.

Thought I had a picture of the "egg" shaped ones. I may still have them out in the garage.

Well I'll have to go look. I'll probably just get new emulsion tubes and jet kit and see if that helps. Thanks.

get aftermarket ones from motion pro, or dynojet, or someone else or the same thing will happen again in time

Shocka311 wrote:

trifgeorge wrote:does it accelerate well when it's on neutral and standing still?

It revs all the way through the rpm range just fine in neutral

It may sound dumb but it happened to me and it could happen to you too if it's the first time you cleaned the carbs. When i cleaned them i mixed the jets in one of the carbs (the jets have the same thread) , and around 5k RPM it boogled. On neutral it seemed to rev up well, but while riding it was slow as f*ck! Go ahead and take a look a the jets in each carb and see if they are placed correctly (the jet with the bigger hole is on the lower step and the one with the smaller hole is on the higher step).

Fizzinatorr wrote:get aftermarket ones from motion pro, or dynojet, or someone else or the same thing will happen again in time

I think Factory Pro has the best deal going still. A set of nickel plated ones for around $100.

trifgeorge wrote:

Shocka311 wrote:

trifgeorge wrote:does it accelerate well when it's on neutral and standing still?

It revs all the way through the rpm range just fine in neutral

It may sound dumb but it happened to me and it could happen to you too if it's the first time you cleaned the carbs. When i cleaned them i mixed the jets in one of the carbs (the jets have the same thread) , and around 5k RPM it boogled. On neutral it seemed to rev up well, but while riding it was slow as f*ck! Go ahead and take a look a the jets in each carb and see if they are placed correctly (the jet with the bigger hole is on the lower step and the one with the smaller hole is on the higher step).

I'll check that. I've gotta pull em out cause i just got a jet kit. Now I have a new question for everyone. The jet kit I got is used and says I have to drill the slides out but the drill bit is missing; what size is it? It also gives options for stage 1 and 3. I'm guessing if my bike is pretty much stock i should use stage 1. Anything else I should consider when installing this?