Strong Smell of Gas and Exhaust

1. All of a sudden my 77 KZ650 has an OVERPOWERING smell of gas. I need to check out the fuel lines, etc, but its the holiday and cant sneak away. Perhaps I will get some time to check tomorrow. Even a police officer who happened to stop near where I was parked was like "wow I smell gas....a lot!"

2. Tomorow I am ordering a Delkevic exhaust for the bike. By all accounts, its a pretty easy install. I have STOCK pipes on the bike now and saw this photo of the same exhaust on ebay.
Ive never swapped exhausts before, and it looks like this exhaust only connects at the usual header area and the rear footpegs. Are there any other places it connects?
Thanks!

No other mounts for the exhaust.
Might want to put something underneath the exhaust to support it while you loosen everything up.

As far as the strong gas smell, I've had that a number of times with my bikes lately.
The KZ has been sitting too long, and I think the hoses between the carbs are leaking, or the T connection.
My ZRX had an issue with the gas tank leaking, then the vent (no overflow on ZRX carbs) on carb 3 started leaking.
Draining the bowl revealed green paint flakes, so the fuel shut off valve and float weren't doing their job.
Draining the carbs seems to have worked, and I have added a fuel filter to the fuel line.

Your 650 has a manual petcock/fuel valve, correct?
Did you shut it off when parked long?
Check your oil level.
If gas leaked through the carbs and into the crankcase, the oil level will be higher.
You will need to drain and change the oil and filter if that happened.

Every carb System will smell/leaking gas over a long time period of non use.
Only injeteted fuel Systems (EFI) are "smell less" if any mice don´t bite the tubes.

Scirocco wrote: Every carb System will smell/leaking gas over a long time period of non use.
Only injeteted fuel Systems (EFI) are "smell less" if any mice don´t bite the tubes.

My bike doesnt sit for more than a week.

Outside in the elements.
Steve

hose and connection, but my kz650 still smells SO strongly of fuel that I got a headache when riding it today. AND my mileage has gone way down. I could go a few days and spend on $3 on fuel and now every two days Im dropping nearly $8 in fuel.

I dont see leaks ANYWHERE!

Could this be spark plug related?

A week ago I got over enthusiastic when using "PRIME" petcock position to start the bike. (the PO but an AFV valve and different petcock on. Its nice that I dont have to remember to turn it off) ...Thereafter I noticed exhaust pipe on cylinder one was cold. Took the plug out and it was black. So I swapped it with the spark plug in cylinder 3 and after that all the pipes get hot as they should. ....

Could the spark plug (s) be causing the poor mileage and gas smell, or is to think so a "stretch?

I have NGK Iridium plugs coming in the mail tomorrow so I will swap out the old, non-iridium ones. I have iridiums in all my bikes.

Sounds like you've got a vacuum petcock of some sort there.
Stock was a manual petcock for a 1977 model, with what? ON OFF REServe.

Prime on the vacuum petcocks will let the gas free flow through the petcock, or at least is supposed to.
Doesn't matter if you leave it on Prime while your starting her, even if it takes a while to start, or if you leave it on Prime and ride away.
Ideally once she starts, you want to turn the petcock to ON.
If you leave it on Prime, and park the bike for some time, and your carb's fuel shut off valves are not doing their jobs, then gas can leak by them and over fill the carb/s.
Smell of gas.

Another possibility, I had an issue with a vacuum petcock.
The diaphragm started leaking, and fuel would go down the vacuum hose into carb #2, flooding it, causing running issues, and a smell of gas.


How is your bike running?

rstnick wrote: Sounds like you've got a vacuum petcock of some sort there.
Stock was a manual petcock for a 1977 model, with what? ON OFF REServe.

Prime on the vacuum petcocks will let the gas free flow through the petcock, or at least is supposed to.
Doesn't matter if you leave it on Prime while your starting her, even if it takes a while to start, or if you leave it on Prime and ride away.
Ideally once she starts, you want to turn the petcock to ON.
If you leave it on Prime, and park the bike for some time, and your carb's fuel shut off valves are not doing their jobs, then gas can leak by them and over fill the carb/s.
Smell of gas.
Another possibility, I had an issue with a vacuum petcock.
The diaphragm started leaking, and fuel would go down the vacuum hose into carb #2, flooding it, causing running issues, and a smell of gas.
How is your bike running?

Thanks for all that.
Im fully aware of the Prime / On / Reserve positions on my non OEM petcock. Its always on "ON" and never left sitting in PRIME....ever!

Bike runs like a top and I hit 90mph today racing some random. I havent noticed anything in terms of not running properly. it just stinks SO bad!!! And like I said. I see no leaks.

Iridium plugs are resistor type. What kind of plug are you using now and are they resistor type? I thought most KZ's use non resistor plugs.

Maybe your carb float needles are getting weak and the fuel level is too high?

Nessism wrote: Iridium plugs are resistor type. What kind of plug are you using now and are they resistor type? I thought most KZ's use non resistor plugs.

Maybe your carb float needles are getting weak and the fuel level is too high?

The NGK that i used was the same listed on Z1Ent: www.z1enterprises.com/ngk-14mm-b7es-spark-plug.html

I decided to get iridiums, just like i did on my Honda CB500 and CB900F Super Sport. I'll let you know if the iridiums blow up the KZ650. At $35 for 4, theres no turning back.

Ive had it with this carb rack. Im getting CR carbs pronto just like I did for my 1982 900F. Bye bye stock carbs. I just hope there is enough clearance to fit pods.:

If you wish to spend $1,000 to solve a $50 problem, that is certainly your choice. However, the carbs and the sparkplugs may not be the problem. As Nessism mentioned, adding an additional resistance in the high tension side of the ignition may actually create a new problem or make an existing one worse.
It is generally best to identify the problem before randomly installing new parts that may complicate matters, but it is your money, time amd motorcycle.

The KZ650 bikes ran perfectly fine in stock trim (mine still does after owning it for 41 years). Changing a bunch of stuff around rather than identifying and correcting a specific problem will usually will lead to more problems, frustration, and plenty of money spent and is still unlikely to make the bike perform as well as it did in stock trim. My stock KZ650-C1 will still starts very easily and will happily run up to 120 mph without a hiccup. I believe the key is simply to perform normal maintenance as described in the manual. But as TexasKZ stated it is your money, time and motorcycle. Ed