[greenmonster]

Some background first...
Bike has been sitting since last October, gas stabilized, etc. Ryan and I worked on the bike earlier that summer, (new chain, sprockets, CCT and valve shims) which included inspecting the carbs and cleaning them. Also synced them and adjusted the air/fuel settings, etc. He did a great job. When all was said and done, bike ran great. Over the next few months, it slowly lost the crisp throttle response it had earlier. I also began to notice a raw fuel smell…especially when the engine was hot, and I’d turned it off for 10 minutes or so. When I went to restart, it would crank longer than usual to fire up, and even when it did, it was a slow and sluggish idle. Also, the gas mileage sucked. Then, last October, I started it up and got a steady plume of whitish blue smoke out the can that and it didn’t burn off…just kept smoking. This had never happened before. So, not knowing what was causing it, I shut her down before any more possible damage could occur, if any. Fast forward to two weeks ago. Drained all the gas from the tank and replaced with fresh. Time to investigate the smoke issue. Take everything off right down to the carbs. Havent touched them yet. Next, oil change. Here’s where it gets interesting. As the oil drains into the catch pan, all I smell is RAW gas!! The oil reeks of it! This is a first! I’m thinking that is what most likely caused the smoke…the gas diluted the oil to the point that it could get into the combustion chamber and cause the smoke. Ive been in touch with Ryan, and he hit the nail on the head…no amount of throttling or running would be enough to dump so much gas into the oil. It must be a carb-only prob. He’s going to temporarily loan me a set of his carbs to see if the problem clears up. If all goes as expected, things will point back to my carbs. I feel its definitely a carb/fuel delivery problem, but what could cause gas to be dumping into the crank case? Im gonna do the visual inspection, use carb cleaner, change the plugs, and go as far as my limited experience with carbs will take me…this will be a good opportunity to learn more. But I need to have a good idea of what direction to take, or I might overlook something that would be obvious to others who’ve dealt with this sort of thing. Anyone familiar with this issue?

Oh, almost forgot...a few years back, the pilot/float(?)-forget which ones-needles were shimmed, each with two .5mm shims, just in case this might be a factor to consider. Thanks for any help!

[spydah]

One possibility is that your rings are junk. Thusly gas would enter into the crank case, and oil would enter into the combustion chamber and make lots of white smoke. The poor performance would be due to lack of compression. You should do a compression test just to make sure that is not whats going on.

[greenmonster]

Originally Posted by spydah

One possibility is that your rings are junk. Thusly gas would enter into the crank case, and oil would enter into the combustion chamber and make lots of white smoke. The poor performance would be due to lack of compression. You should do a compression test just to make sure that is not whats going on.

Thanks for your input, Spydah. The bike has 17K miles on it...never beaten. It's a '97. From what youre saying, if my rings are shot...any unburned gas going into the combustion chamber is making it past the rings....into the oil, and then coming back up past the rings and then burning as the smoke? Do I have that right? That would mean an awful lot of gas is going unburned and getting past the rings...I forgot to mention...Ive only put 500 miles on since last summer and fall, right before the smoking started in October, and this started all at once...if my rings were going, wouldnt the smoking be a gradual thing?

[Uncle Snake]

My money's on a stuck float in one of the carbs,. Seems like most often it's the one on the shifter side. Float sticks and fuel keeps flowing. Good luck sorting it out. Regards, Jake

[GixerJockey]

It's also possible that its something as stupid as leaving the petcock in the "prime" or gravity feed psoition...

[greenmonster]

Originally Posted by GixerJockey

It's also possible that its something as stupid as leaving the petcock in the "prime" or gravity feed psoition...

Hmmmmm....that didn't occur to me....well, during the riding season, I leave the petcock in the "on" position. I dont turn it to "off" at the end of a days ride. I was under the impression that you could leave it on until you had a reason to turn it off, like taking off the tank, etc. Arent bikes today designed so that it can be left on? Not sure...

[greenmonster]

Jake...thats a good point...stuck float...I picked up some carb clean today. I hope it really is just a stuck float, some gunk or whatnot. Wish I had EFI!!

[Terry]

Had the same problem with a GSXR. It was stuck floats.

[Ericthejet]

My $ is on a stuck float(s).
The gas can flow backwards it would seem into the airbox and drain into the crankcase. Clean carbs, floats will do their job holding back fuel flow once up to their proper level.

[Doc]

Originally Posted by Uncle Snake

My money's on a stuck float in one of the carbs,. Seems like most often it's the one on the shifter side. Float sticks and fuel keeps flowing. Good luck sorting it out. Regards, Jake

[greenmonster]

Originally Posted by Uncle Snake

My money's on a stuck float in one of the carbs,. Seems like most often it's the one on the shifter side. Float sticks and fuel keeps flowing. Good luck sorting it out. Regards, Jake

Why is it more often on the shifter side? Is this true of most I-4 bikes, or Kawi's in particular?

[Ericthejet]

If the bike is on it's side stand then that would be the lowest point for the gas to flow.

[greenmonster]

So, what practice do most of you use...turn the petcock off after a days riding, or leave it on throughout the season?

[04ZRX]

My money is on the petcock.

I have a vacuum operated petcock, meaning that when the bike starts the vacuum now pulls on a diaphram that opens the petcock to allow fuel delivery. When the engine is shut down, no vacuum, petcock is shut off.

The problem with that design is I have 3 positions on my petcock:

On
Prime
Reserve

But no off

So, when this contraption fails, it allows the fuel to be on at all times.

Kawi petcocks have become famous for this problem with filling the crankcase full of fuel.

There are two fixes, of course on is temporary.

1. Buy the two seals (O-rings) for your petcock & replace them.

2. Buy a Pingle brand petcock which has a true off position on it.

[Ericthejet]

I too have had issues in the past with the same setup.
I rebuild my fuel tap every 2 tears just to be safe.
2 things have to fail in order for gas to flow freely. One is the tap itself. If the diaphram fails to re-seat it will allow the fuel to flow. Your floats have to be stuck open to allow gas to keep flowing. If the tap fails and a float fails then you will get fuel running amuck.

Get a fuel save jar, disconnect your fuel line at the carbs and test the operation of the tap to be sure.

[Kitt]

ur floats are sticking... these bikes have a lot of vibration and precision stuff likes to get jammed up... I had this problem on my f2 all the time, one more beuatiful reason i love my FI