1986 FZ600 issues

[fz600newbie]

Hey everyone I am new to the forum. I have a 1986 fz600 that I picked up for cheap, great deal. I cleaned the carbs and changed the oil and the bike started up great. I ran it for bout 50 miles and let me say, this bike loves turns, sharp turns long turns it eats them up. Bike shifts super smooth its awesome, but then it started bogging down and shut off, a few mins later and it started back up again. then shut off after bout a mile.

i got it back home and i noticed my far right carb was leaking fuel, badly. So I drained my oil and yeah, quite a bit of fuel in my oil. Could that be why it was shutting off?

I have adjusted and readjusted the floats countless times, I am now looking at any alternative leaks, when I take the carbs off and stick my finger into the intake all are dry except for the far right intake. I am also using K&n pods instead of the stock airbox......it came that way and I have looked for the stock airbox and have had no results. Could that also be an issue?



I am very new to working on motorcycles, any advice will be greatly appreciated. This was supposed to be my daily driver and for now im stuck walking 3 hours to work until I get this machine back on the road.

 

[Caladin]

The 86 FZ600 was a fun bike. I had one for a few years before my FZ6.


Im not a mechanic, but I would stard with the basics. How do the spark plugs look? I'm guessing that the far right one may be fouled.

Check the plugs, change the oil, check for leaks around the carb boots and if that doesn't fix it then rebuild the carbs.

I had the K&N pods on each carb as well as a Kerker pipe. I found rejetting was necessary. It took a lot of playing around to get it running good.

There is a Haynes Manual available for the FZ600 as well. You might find that helpfull.

 

[Fred]

The carb is flooding. You need to replace the float needle.

Fred

 

[Shamus McFeeley]

Pod filters do not work with vacuum operated carbs without extensive tweaking. Even if you have direct lift carbs, some re-jetting will be necessary.

If there is an excessive amount of fuel in the oil, then you must be running so rich that you are experiencing "gas wash". Like Fred said, the float needle is also suspect. Check your needle bore for varnish or build up, even the slightest amount can cause it to stick. I had the very same problem on a 80 Honda due to ethanol build-up.

 

[TownsendsFJR1300]

Besides a new needle and seat, make sure the float itself is not leaking, it'll fill with fuel, sink and leave the valve wide open causing the flooding.

If available, I'd probably change it out anyway due to its age..

Make sure your measuring the float level with the carb upside down, usually without the gasket on the main body...

 

[tuningfork]

Glad to see you are keeping a classic on the road. Make sure the "starter" (ie choke) plunger is working properly on that carb as well, the excess fuel could be getting drawn in through that circuit and getting blown back out by reversion pulses.

 

[Motogiro]

The carb is flooding. You need to replace the float needle.

Fred

I had a carb where the float lost integrity and wouldn't float anymore. The needle was good but carb was flooding out the overflow. Some floats have an adjustment tab and it could also be adjusted wrong or even assembled incorrectly.

 

[fz600newbie]

wow thanks guys, a whole lot of info!

I readjusted my float and I am about to test for leaks again, all my seals are fine, my needles look clean, and the rubber nose looks great. I guess I could get a magnifying glass to double check.


extensive tweaking for individual pods? What do you mean by that....should I take it to a shop? I have looked everywhere for the stock airbox but cannot find it, I would rather keep the bike stock.






update. I swapped out float valves and such between the carbs and have come to the conclusion that one of the float valves is scratched or dirty where the float needle nose rests....I am gonna get a magnifying glass and see what I can do about that, I cant find replacement parts online

 

[bigbobmegadeth]

I'm going through the EXACT same thing with my bike. 86 fz600. I have the K&N pods. After cleaning the carbs I realized I was in over my head and took it to the local performance shop. They completely disassembled the carbs and washed all the little pieces in some type of machine. They also had to re-jet. 250 bucks and the bike is running sweet. Also make sure there is no rust in your gas tank, I had them do a gas tank liner thingy...

Sorry I'm a major newb, this is my first bike.

 

[tuningfork]

wow thanks guys, a whole lot of info!

I readjusted my float and I am about to test for leaks again, all my seals are fine, my needles look clean, and the rubber nose looks great. I guess I could get a magnifying glass to double check.


extensive tweaking for individual pods? What do you mean by that....should I take it to a shop? I have looked everywhere for the stock airbox but cannot find it, I would rather keep the bike stock.






update. I swapped out float valves and such between the carbs and have come to the conclusion that one of the float valves is scratched or dirty where the float needle nose rests....I am gonna get a magnifying glass and see what I can do about that, I cant find replacement parts online

You will probably have to go to a dealer for the carb small parts. Or you can try bikebandit, they may be able to get what you need, here is a link:
1986 Yamaha FZ600S Parts, 1986 Yamaha FZ600S OEM Parts - BikeBandit.com

 

[tuningfork]

I'm going through the EXACT same thing with my bike. 86 fz600. I have the K&N pods. After cleaning the carbs I realized I was in over my head and took it to the local performance shop. They completely disassembled the carbs and washed all the little pieces in some type of machine. They also had to re-jet. 250 bucks and the bike is running sweet. Also make sure there is no rust in your gas tank, I had them do a gas tank liner thingy...

Sorry I'm a major newb, this is my first bike.

There is no shame in taking it to the pros! On the older bikes a complete dip/ultrasonic clean is sometimes needed to get all the minute gum and buildup out. A shop with AFR probes and a dyno can usually make quick work of the setup. Good point about the rust too. Lets see a pic of the old beast!

 

[bigbobmegadeth]

Pics will be up later today. The shop I took it too does have a dyno but I don't believe they put my bike on it.

 

[bigbobmegadeth]

Pics up as promised

 

[zombieflamingos]

Im so glad im not the only one with carb issues around here! Ive taken mine apart about 7 times now. Finally got my bike running yesterday after 2 months of messing with it. Im still having issues with idle RPMs though.

Im not sure if its my throttle cable sticking or if its the idle screw needs to be adjusted.

 

[TownsendsFJR1300]

Im so glad im not the only one with carb issues around here! Ive taken mine apart about 7 times now. Finally got my bike running yesterday after 2 months of messing with it. Im still having issues with idle RPMs though.

Im not sure if its my throttle cable sticking or if its the idle screw needs to be adjusted.

What is doing or not doing?

 

[aclayonb]

Pod filters do not work with vacuum operated carbs without extensive tweaking. Even if you have direct lift carbs, some re-jetting will be necessary.

If there is an excessive amount of fuel in the oil, then you must be running so rich that you are experiencing "gas wash". Like Fred said, the float needle is also suspect. Check your needle bore for varnish or build up, even the slightest amount can cause it to stick. I had the very same problem on a 80 Honda due to ethanol build-up.

+1. And sometimes, they never work right. The most evil thing about sexy, older bikes is that they usually have about $500.00 worth of rubber that needs to be replaced and another $500.00 worth of random parts that need to be replaced. I worked on a CB750 for a while trying to get the carbs synced and working right. It was a beast and I ended up replacing the carb insulators, carb boots, airbox seals, $280 worth of rubber in the carbs, and ditched the K&N air filter for a cheap emgo paper filter. I sonically cleaned them (cheap, harbor freight sonic bath) and resynced them with a manometer. It was a pretty lengthy endeavor and the thing never did run as good as a crappy fuel injected bike.

 

[aclayonb]

Carb issues are always electrical, by the way. Just sayin'. A new battery, new plug wires, new plugs, and new copper between the three does wonders for carb issues.

 

[The_Paragon]

Ohh gawd.. I had a 1986 fz600.. I poured TONS of money in the bike.. stator, multiple charging rotors.. reg/rectifier. Still never charged well! Carb boots... etc... etc... etc...
It was probably the coolest bike ive ever owned though! Definitely got a ton of looks on that bike!.

The best day was when I sold that bike.. it was cool.. but it was getting worked on more than getting ridden.

... and its replacement was my 2009 fz6!

 

[TownsendsFJR1300]

Guess I missed something.

I still don't know what the actual issue is with Zombies bike..

High idle, slow to idle down, won't idle?

 

[zombieflamingos]

Hey sorry it took me awhile to get back to ya.

Start up it idles fine but then slowly starts increasing rpms on its own. On Tuesday when i finally got it started after 2 months of replacing and cleaning ****. It would idle fine sitting there but when you actually rode it and came to a stop it would ramp up to 4K and wouldn't drop down until you release the clutch to move. I'm wondering if maybe the throttle cable is sticking? Im not sure.

Im not going to lie, i was just wicked excited to get it running. Its been a 2 month struggle with those damn carbs. Cleaned them, replaced gaskets and needles. Might as well be brand new now. Haha.


Humor me just a little here, im a newb in the bike world. This is my first bike, picked it up for damn near free. I have a degree in diesel service but bikes are a little different then a tractor. hahaha!!