88 FZ600 idle hovering, dies at intersection

[Messy]

I have an 88 FZ600 with a fuel issue. Heres the facts:

-New carbs
-rebuilt pet****
-PO told me the bikes jets needed cleaning and the bike runs LEAN
-I smell gas in the exhaust fumes so I say RICH
-Bike dies everytime I'm not constantly on the throttle
-I just adjusted the idle and it just hovers from 700ish to 1100ish
-My fuel gauge is telling me I'm getting about 85 miles to the TANK

Is this the jets or a vacuum problem? Is this common? thank you all in advance!

 

[SovietRobot]

I have no idea honestly because I've never worked on a carbed bike.

But I can suggest, the only real way to tell if it's running rich is to pull the plugs and see if they're fouled.

 

[TownsendsFJR1300]

You may try using some Seafoam which works good but it sounds as if your due to have your carbs cleaned. You can pull the 4 (attached together) and then the fuel bowls. Try to empty the bowls into a small clean container to see what crap comes out.. The fuel bowls will allow access to the jets. There will probably be a bunch of varnish in there and the jets clogged up, especially the idle jets which have much smaller orifices. An air compressor with carb cleaner would do it. For the really small orifices I use a piece of wire from a wire brush(used to clean welds) clamped to a small vise grip. Some of the holes are that small. Go slow and do one at a time. It MUST be spotless.

 

[shuckle]

You may try using some Seafoam which works good but it sounds as if your due to have your carbs cleaned. You can pull the 4 (attached together) and then the fuel bowls. Try to empty the bowls into a small clean container to see what crap comes out.. The fuel bowls will allow access to the jets. There will probably be a bunch of varnish in there and the jets clogged up, especially the idle jets which have much smaller orifices. An air compressor with carb cleaner would do it. For the really small orifices I use a piece of wire from a wire brush(used to clean welds) clamped to a small vise grip. Some of the holes are that small. Go slow and do one at a time. It MUST be spotless.

I second that, my '86 FZ750 had similar symptoms and was dirty carbs.

 

[Hellgate]

+3, clean the carbs and the fuel screen and replace the fuel filter, if there is one. Replace the air filter if dirty and check the spark plugs. If black and fouled replace them. Finally, is the gas new or old? If the gas is more than three months or so replace it.

Here's a guide on how to adjust CV Carbs: CV Carb Tuning Procedures

The FZ600 is a great bike and was not prone to ride-ability problems.

 

[The Toecutter]

sounds like a vacum leak.start it up and spray the carbs with carb cleaner,and see if it effects the idle and if it does this will help you to pin point your leak.

 

[The Toecutter]

i just thought of something else it could be.do you still have the correct airbox and filter on the carbs?because the vacum opperatted carbs have to be semi-restricted on their air intake to be able to pull a proper idle vacum.

 

[Messy]

i just thought of something else it could be.do you still have the correct airbox and filter on the carbs?because the vacum opperatted carbs have to be semi-restricted on their air intake to be able to pull a proper idle vacum.

First let me say thanks to everyones replies, its ALOT more than I've gotten from any other forum on this bike so far. The carbs were bought off the internet by the PO and installed by him. Everything should be completely stock from what he told me and I have no reason to coubt him seeing as how nobody would lie about extra money put into a bike they were trying to sell.

Ill pul the carbs and clean them I suppose. I REALLY need a Clymers or equivelant for this thing. Anyone know where I can download a free one online for the time being? I'm kinda broke. Thanks again.

 

[n1one]

I agree that to determine if it it is running rich, check each plug to see if they are wet and fouled. It only takes one to have an issue.

Another trick is to remove the filter from the air box and smother (using a very clean rag, don't let go of it) the intake of each carb seperately. If the RPMs increase, then it is running to lean. If the RPMs drop and die, then it is running to rich.

Here is a diagram of the carbs for your bike:

View attachment 18188

Also, you can download an FZR600 service manual here(be patient you have to wait 60 seconds for the download to start):

Download PDF Yamaha FZR600 Service Manual | PDFTown.com

Good Luck!:thumbup:
Don"t Give Up!

 

[Messy]

Thank you, Ill try that. That PDF isnt for my bike though, I have an 88 FZ600, that looks like a brand new FZR model.

 

[OZXJR]

I have had the same problem with a '76 Z1000 and a '98 CBR600.The carbs need a clean .

 

[Messy]

Dude tha is the funniest f**king avatar I've ever seen. Thanks by the way, I'll clean the carbs but its just so hard to keep my bike off the road.

 

[cfd37buckeye]

Yup, I have an 88 FZ, ran great for the last few days, and yesterday it decided it was no longer going to idle. Pulled the carbs, drained the bowls, cleaned the jets, and it is fine now. Dirty carbs on these things are the biggest problem.

 

[champion221elite]

Probably wouldn't hurt to clean the fuel tank as well. I did this on my old 1974 Honda CL 200 by removing the tank and filling it with copper BB's. I spent a few hours rolling those bb's around with a mixture of gasoline to remove some rust and sediment that had collected in the tank after sitting for 20 years.

This helped keep my fuel filter and carbs much cleaner.

 

[tuningfork]

Hmm, lots of "old iron" showing up on the boards.. I thought my FZR600 was an old bike...FZ600 Its like meeting your great great grandpa!

Frankly before messing around with it too much more, I would disassemble and "dip" the carb bodies. AutoZone sells a nasty carb dip solution (comes in a paint can) that will get rid of ANY junk in the carbs. It will destroy any plastic pieces too so you have to do a full disassembly to use this stuff. The suggestion to clean the tank (off the bike) was good also, if you have any rust in there it will be a perpetual clogging issue.

I had really good luck with the Yamaha brand carb dip as well, had a set of pilots that were nearly blocked solid varnish, overnight soak in a glass jar and they were perfect. The dip is a much quicker working product though (15min-1hr or so).

If you can get it to idle you can use a IR temp gun to check the header temps, they should all be within about 25 degrees F of each other if it is balanced correctly and if all the cylinders are firing. Somewhere around 400F is a reasonable target at say 1" from the block. You can play with the sync and the pilots and see pretty dramatic changes in temp...if you do this and see no change then something is plugged up and a dip is probably going to be needed.

It is important to blueprint the float heights as well..this sets the fuel level in the bowls which can have a large impact on the bike running rich or lean. You'll need the service manual for this spec.

When you pull the carbs look at the rubber mounting boots, they may be cracked which will cause vac leaks and idle issues. It is also possible the sync/idle speed is way off. Given the low mpgs my $$ is on some plugged up ports in the carb, incorrect float height and probably some worn needles/needle jets.

 

[biker1984]

hi there i may be saying something obvious here but have you tried turning the idle speed adjuster up its between the lower of the carb and the airbox (and is impossible to get to but you can knock it round with a flat head driver well enough ). i ride an 88fz600 streetfighter ( [ame=http://www.youtube.com/watch?v=h7No8oS3gpI]YouTube - 1988 fz600 streetfighter project[/ame] ) and mine will idle happily at 1100 - 1500 (higher idle also stops the clutch chattering so much ) as for weather your running to lean or to rich - to rich by far. i get 120miles from full to reserve with idle jets running 2.5 turns out as factory standard. i hope you get it sorted good luck.

 

[sniff6]

I REALLY need a Clymers or equivelant for this thing. Anyone know where I can download a free one online for the time being? I'm kinda broke. Thanks again.

Here you go m8 uploaded it myself : Haynes workshop manual also included the wiring diagram :thumbup:

4shared.com - online file sharing and storage - download Yamaha_XJ_600_FZ_600_YX_600_1984_1992.rar