Strong Smell of Gas and Exhaust

Street Fighter LTD wrote: 1 as noted you have at least one fouled plug and are now changing them all. Good.. Personally I never use a fouled plug once discovered as they never seem to perform properly after they are fouled. I call it gas soaked , and they never give complete combustion after becoming fouled. My educated guess is at least some or all of the gas smell is raw fuel passing thru the motor and puking out the exhaust pipe.
2 Now this doesnt account for what caused the fouling in the first place . So its time to check all systems . Logic is something that was recently touched is not right.
Carbs is where I would look first as dirt or bad fuel may be at fault. Also checking all tune up items and rebuilt areas ( Did something loosen or get overlooked ? )
3 So now once the plugs are replaced run the bike and see if the problem still occurs , and if so is it from the same cylinder that fouled the 1rst plug ?
A broad statement is to tell you to recheck all adjustment which keep a motor running properly. Compression , timing ,good spark, valves, fuel flow from tank, carbs done right?
If you want the CR carbs , thats fine , but I would still want to get the bike running back to its normal baseline of performance. As otherwise the bike with new carbs may still have the same current problem
Hope this helps
Happy New Years
Dave

Super helpful. Thanks.

Compression was checked in mid November. Across all cylinders it was 140-150.

Wish I could buy you a beer

650Dude wrote: 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!

UPDATE!

It was the spark plugs. A week ago when starting it up I left it in the prime position for WAY TOO LONG and the plugs were crap. 2 of them looked OK but the other two, NOPE!

Put in the NGK 6664 Iridium plugs and MAN this bike RUNS! I never felt that "whoosh" when you hit the powerband at a certain RPM, but today I took the bike upstate and did 110MPH (true 110 MPH because I have a navigation and speed app on my phone) and the bike felt like it wanted MORE.

Amazing little bike, these KZ650s.

No more smell of gas - seems all is well in KZ-Land.

Been spraying penetrant oil on the exhaust studs and they are cleaning up nicely. Cant wait for my Delkevic 4 into 1 to arrive so the bike can ROAR like my 900f.