'86 FZ600 choke?

[sevenhills1952]

Hello. I'm new here, retired. I have an FZ600 I bought new, 1850 miles on it. It's been sitting in garage 30 years. I removed tank and emptied it back then. Recently thoroughly washed bike, changed oil, new battery, 4 carburetors were gunked up.
I got rebuild gasket kits , soaked, blew passages out, etc. They looked new. I put in non-ethanal (real) 90oct gas. It runs great!
Problem is starting. I choke it, only way to start it is starting fluid I spray into air box.
Once warmed up it restarts fine.
Any assistance or ideas much appreciated.

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[TownsendsFJR1300]

Sounds as if your choke is not functioning / still clogged.

Click on this link, part #24 is for your choke: https://www.partzilla.com/catalog/yamaha/motorcycle/1986/fz600s/carburetor-fz600s-sc

You obviously don't have a butterfly choke and the carbs each have orifices that allow EXTRA FUEL to flow when activated.

I would start at part #24, and follow the fuel circuit, (you should be able to see the casting, which direction that orifice goes and it may very well change directions several times).

Lots of carb cleaner, pressurized air and possibly a carb jet cleaning tool may be needed.. More than likely, it's still clogged at the lower end (float bowl) area of the carb.

I'm assuming you have a lever (or some sort) to activate the choke, it's assembled correctly and you are using it...

 

[sevenhills1952]

Sounds as if your choke is not functioning / still clogged.

Click on this link, part #24 is for your choke: https://www.partzilla.com/catalog/yamaha/motorcycle/1986/fz600s/carburetor-fz600s-sc

You obviously don't have a butterfly choke and the carbs each have orifices that allow EXTRA FUEL to flow when activated.

I would start at part #24, and follow the fuel circuit, (you should be able to see the casting, which direction that orifice goes and it may very well change directions several times).

Lots of carb cleaner, pressurized air and possibly a carb jet cleaning tool may be needed.. More than likely, it's still clogged at the lower end (float bowl) area of the carb.

I'm assuming you have a lever (or some sort) to activate the choke, it's assembled correctly and you are using it...

Thanks so much. Great advice and I should have had that diagram when I had the carbs apart. I thought after all the extensive soaking, cleaning and blowing out it would be fine, apparently as you said a clogged fuel passage. I'm assuming all four are clogged. Yes, I'm choking it. It runs great once started.
All the best and I'm printing that diagram!

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[TownsendsFJR1300]

Neat bike!

As noted, start where the choke assembly goes into the carb body. You should, just looking and tracing, see casting go down INTO THE FLOAT BOWL.

That's where the carb will pick up extra fuel. It'll likely be a very, very small orifice (for each carb, maybe a small brass "casting" around the opening... That little hole will varnish up easily if old fuel is left for a long time, especially if not treated...


I did a Suzuki 230cc carb, (dirt bike-carb brought to me in pieces by a customer), but had the same exact issues as you. No start cold..

Tried blowing carb cleaner thru the top, wouldn't go anywhere... The casting went back and forth, sideways, no way to run a single strand thru it. I eventually did 3-4 heated runs thru the sonic cleaner. That, 150 PSI of air, carb cleaner and it finally opening up... That too, had it's pick up deep, at the lowest point of the bowl...

Most of your clogging will very likely be at that end, where the fuel sat... Once you can blow thru and cleaner comes out the other end, your good to go, three more to do!!

Plz holler back with your results...



A small carb before and after Sonic cleaning:
As you can see, the varnish is the worst at the bottom (on this engine, where the main jet is).

 

[sevenhills1952]

Neat bike!

As noted, start where the choke assembly goes into the carb body. You should, just looking and tracing, see casting go down INTO THE FLOAT BOWL.

That's where the carb will pick up extra fuel. It'll likely be a very, very small orifice (for each carb, maybe a small brass "casting" around the opening... That little hole will varnish up easily if old fuel is left for a long time, especially if not treated...


I did a Suzuki 230cc carb, (dirt bike-carb brought to me in pieces by a customer), but had the same exact issues as you. No start cold..

Tried blowing carb cleaner thru the top, wouldn't go anywhere... The casting went back and forth, sideways, no way to run a single strand thru it. I eventually did 3-4 heated runs thru the sonic cleaner. That, 150 PSI of air, carb cleaner and it finally opening up... That too, had it's pick up deep, at the lowest point of the bowl...

Most of your clogging will very likely be at that end, where the fuel sat... Once you can blow thru and cleaner comes out the other end, your good to go, three more to do!!

Plz holler back with your results...



A small carb before and after Sonic cleaning:
As you can see, the varnish is the worst at the bottom (on this engine, where the main jet is).

Thanks so much again. I ordered carb jet cleaning tools like you mentioned. This camel whiz ethanol really causes problems. Our old (50s-60s) cars I'm replacing the gas tanks, then using pure gas.

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[TownsendsFJR1300]

Thanks so much again. I ordered carb jet cleaning tools like you mentioned. This camel whiz ethanol really causes problems. Our old (50s-60s) cars I'm replacing the gas tanks, then using pure gas.

Sure does... It keeps me busy cleaning and repairing most small gas engines, (weed eaters, blowers, chain saw's, especially generators).

I also use "Gas-Shok" as a stabilizer and Yamaha's Ring Free (a fuel system and top end cleaner) in EVERY gas machine I own...
No more problems after that...

 

[sevenhills1952]

Thanks once again! Where can I buy Gas Shok? Yamaha products are no problem to get, but that additive I can't find. It has good reviews.

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[TownsendsFJR1300]

Thanks once again! Where can I buy Gas Shok? Yamaha products are no problem to get, but that additive I can't find. It has good reviews.

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I get it at my local marina. It's pretty popular in the marine world (as is the RF). Most marina's should have it. I never really looked on-line for it.

The RF you can order and get cheaper on line... Your fuel will last easily a year with it with NO varnishing...