Bad Gas????

[The CyberPoet]

Well as far as the spark problems, the bike had the full tune up last week, and they replaced the plugs along with syncing the carbs and cleaning them out. It was a Kawasaki dealer; not that should make a difference, but I was wondering for a minute, if they synced the carbs right?

It is virtually impossible for a professional mechanic to poorly sync carbs; the act of syncing them is very very simple.

How often would a petcock diaphram go bad and is it easily detected by a mechanic during a tune up and test run?

Petcock diaphram is a rubber sheet, pushed on by a spring (to close) and pulled on by engine vacuum (to overcome the spring when the engine is running); the PRIME setting bypasses the routing past the diaphram. The diaphram can dry out and become brittle, esp. if the bike is parked for a very long period without fuel or with water in the bottom of the gas tank. Unless it is specifically what the mechanic is looking for, it is unlikely to be spotted, because the symptoms occur after a certain number of miles, when the carbs are starved for fuel (usually high RPM highway riding).

As far as the water in the gas tank; could that be from watered down gas or maybe rain got to it?

No one waters down gas, because gas and water don't mix. Hence, if you find water, it means that water got into the tank somewhere other than at the pump, such as condensation when sitting (common), or past a bad gas tank cap seal (less common), or because the gas cap drain tube is blocked/kinked or connected to something it shouldn't be (like to a vacuum connection on the carbs).

I mean, there IS some rust around under the gas door. But thats always been there since I bought the bike in the beginning of the summer; and its only been this week that I've had this problem.
The only other modificatin that I did was replace the choke cable , but that was about a month ago.

If there is rust around the gas cap door on a bike that is 5 years old or newer, it's a sure sign that there is water building up around the gas cap and not draining correctly, and that the tank needs to be checked for both water presence and rust. This is an area that should not rust that quickly (if the bike were a decade+ old, it would be a different story).

side question: Do 98+ Kat's have one headlight on normal or two?

98+ Kats all have dual headlights from the factory and both headlights should burn in both beam positions (high beam and low beam).

Cheers
=-= The CyberPoet

[Scott]

Well as far as the spark problems, the bike had the full tune up last week, and they replaced the plugs along with syncing the carbs and cleaning them out. It was a Kawasaki dealer; not that should make a difference, but I was wondering for a minute, if they synced the carbs right? How often would a petcock diaphram go bad and is it easily detected by a mechanic during a tune up and test run?

As far as the water in the gas tank; could that be from watered down gas or maybe rain got to it? I mean, there IS some rust around under the gas door. But thats always been there since I bought the bike in the beginning of the summer; and its only been this week that I've had this problem.
The only other modificatin that I did was replace the choke cable , but that was about a month ago.

side question: Do 98+ Kat's have one headlight on normal or two?

[The CyberPoet]

I suspect, given the symptoms you listed, it's either:

Fuel Delivery Problems:
(A) Defective petcock vacuum diaphram. Next time it does it, switch the fuel selector to PRIME and see if the problem "disappears" almost immediately (switch back to ON after 45 seconds if it doesn't correct the problem and rule out the petcock diaphram; if it does fix the issue, replace the vacuum line to the petcock and the petcock diaphram); OR
(B) Kinked fuel line between the petcock and the carbs; OR
(C) Fuel filter not running down-hill the whole way (the exit must face straight down to work well; gravity fed fuel system in the Kat); OR
(D) Water, contamination and/or rust in the tank (check gas tank visually with flashlight, hook petcock output to hose and put hose in glass jar, then switch to PRIME temporarily to fill about a cup into the jar & shake bike a bit while filling jar -- check fuel in jar for water, discoloration indicating contamination, metal specs indicating rust).

Spark Problems:
(E) Fouling spark plug (usually caused by faulty carb fueling); OR
(F) Borderline defective coil (easy to measure using an ohm-setting on a multimeter); OR
(G) Bad plug wire (again, easy to measure).

At this point, I'm guessing (A) or (D).

Cheers
=-= The CyberPoet

[Scott]

2000 Katana 600cc bone stock 5800 miles: I got the carbs cleaned and full tune up, oil and filter last week, so the bikes been running smooth since then. Although recently, I put in Shell 93 Octane about 3 days ago. Twice actually. Last time was yesterday but a different station.
The bike runs fine for awhile, but every now and then, the bike starts tp slow down after 60 - -80 mph in 6th gear, and then sputter till 45. It stays around 45 even if I down shift to try to pick up speed, then if I slow down and go to first it cuts off and I got to rev the hell out of it to get it to start up.
Took it back to the shop and the guy suggested it was bad gas and even test rode it for a few minutes. Of course the problem didnt kick in when he rode it, but sure enouhg later on that day it happened again.
How long if this is bad gas, will it take to flush it out of the system, or do I have to reclean the carbs now?
Or is it something else maybe they did something wrong?