Bad Gas????

[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?

[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]

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]

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

[md86]

Bone-stock 600 ...... don't waste your money on 93 octane . 87 will do you fine .

[md86]

This has been discussed to DEATH before , and the general concensus is that 87 is just fine for stock bikes . Your buddy never bothered to look for the correct info , apparently . It happens . It's in the manual , AND on a sticker on the bike somewhere .

[mystahagy]

This has been discussed to DEATH before , and the general concensus is that 87 is just fine for stock bikes . Your buddy never bothered to look for the correct info , apparently . It happens . It's in the manual , AND on a sticker on the bike somewhere .

Mine says 91 on that metal tag on the left of the steering head.

[The CyberPoet]

Mine says 91 on that metal tag on the left of the steering head.

91 RON, not 91 PON.
RON is used in Europe.
PON is a calculated formula that is (MON+RON)/2 = PON.
91 RON is normally the equivilent of 87 PON.

Unless, of course, the 750 you put in there isn't a standard Kat 750, but something with a higher compression ratio...

Cheers
=-= The CyberPoet

[mystahagy]

Mine says 91 on that metal tag on the left of the steering head.

91 RON, not 91 PON.
RON is used in Europe.
PON is a calculated formula that is (MON+RON)/2 = PON.
91 RON is normally the equivilent of 87 PON.

Unless, of course, the 750 you put in there isn't a standard Kat 750, but something with a higher compression ratio...

Cheers
=-= The CyberPoet

ohhhh SNAP! I just got pwned I just done lernd somethin new, thanks for correcting me. but yeah I do run higher because of the engine, that thing hates 87.

[Scott]

Well only one light comes on when I start my bike unless I hit the highbeams. Wonder why that is. I bought a brand new battery in the beginning of the summer and it died out a month later. Sometimes I had to physically shake the bike in order for the battery to kick in. I had to fully recharge it at a gas station. Now its fine. But I thought that was probably due my choke cable being frozen for awhile and the bike being flooded a few times when I would try to start her up without it turning over properly, eventually killing the battery. The spark plugs fouled out and were replaced. Before that I eventually bought a new choke cable and replaced it with a friend's help.
I dont think the guy I bought the bike from kept it indoors or even had a tarp for it, so thats the only reason I figure theres rust by the gas cap door.
Fixing that sounds like a mess. Should I just say screw it and find a new gas tank?
And how do I tackle fixing the light problem? Sounds electrical.

[Anonymous]

It sounds like starvation issues

[The CyberPoet]

Well only one light comes on when I start my bike unless I hit the highbeams.

Replace the bulb for the light that doesn't have both beams. The filament broke.

I bought a brand new battery in the beginning of the summer and it died out a month later. Sometimes I had to physically shake the bike in order for the battery to kick in. I had to fully recharge it at a gas station. Now its fine. But I thought that was probably due my choke cable being frozen for awhile and the bike being flooded a few times when I would try to start her up without it turning over properly, eventually killing the battery.

Get a BatteryTender brand battery charger and leave the bike plugged in when not in use. The batteries for bikes lose 25 to 40% of the long term ability to hold a charge every time they are drained; drain it three to five times and it won't hold enough of a charge to start the bike. Keeping the battery charged up all the time will extend it's lifespan and ensure fewer problems.

I dont think the guy I bought the bike from kept it indoors or even had a tarp for it, so thats the only reason I figure theres rust by the gas cap door.
Fixing that sounds like a mess. Should I just say screw it and find a new gas tank?

Not until you get in there with a flashlight and check out the problem. Even then, simply etching away the rust may be sufficient (light surface rust) or etching and sealing (to create a rust-proof barrier) is far more cost effective. See CyberPoet's "How to Deal with Rust in your Metal Motorcycle or Boat Gas Tank" -- at MotorcycleAnchor.com makers of the best motorcycle security solutions in the USA. for more info.

Cheers
=-= The CyberPoet

[Scott]

Good info thanks guys.

What did you mean by 'starvation issues'? Oil? because that was changed last week and I dont wheelie or anything.

The shop offered me to bring it in again if the problem continues. I think they'll probably try to reclean the carbs thinking its bad gas. Should I offer them these suggestions or is that a bad idea?

[The CyberPoet]

Good info thanks guys.

What did you mean by 'starvation issues'? Oil? because that was changed last week and I dont wheelie or anything.

He means fuel starvation (back to items A-D in my first post), not oil starvation.

The shop offered me to bring it in again if the problem continues. I think they'll probably try to reclean the carbs thinking its bad gas. Should I offer them these suggestions or is that a bad idea?

You can feel free to give them the list, but before you bring it to them, you may want to investigate some of this yourself and see if they are planning on addressing any of it for free (lest you end up coming way out of pocket on it, far more than you might have planned).

Cheers,
=-= The CyberPoet

[Scott]

Well my bike died on me last night so I had to park it in a lot by a shopping mall. Sucks. I was riding in 5th gear and it just started to go slower and slower till I had no more pull at all and it cutt off.
My friend for some reasons thinks they synced the carbs wrong and has offered to take a look at it. He's had bikes for years, mainly the Gixxers.
As far as the rust in the tank issue, I've been riding the bike since June, and this week is the first ever type of experience that I've had these issues. I would think that these issues would have shown up earlier since I've been riding it practically everyday to work and on weekends. Once or twice early on I got caught in the rain, and one or two days I had the bike out on a hot day for about 4 hours. No issues on either one of those days. The only issue I had before I sent it n was the sticky idle (staying at 2k- 3k when revving it up at idle). Other than that, it was just the frozen choke cable which I replaced. But if it is water in the tank/rust, It's just wierd to me that it would act up now, especially after I got the bike tuned at the shop.