Carb Leaking, couple questions for testing OFF the

djturnz wrote: It did fill the bowls on prime, but did not over flow. I figured that maybe because the carbs sat totally dry for two weeks, maybe the seals needed some rejuvenation, so I decided to reinstall the bank.
I pulled the air box boots so the carbs would go in easier. It seemed to run fine, no drips. After 3 minutes, I sprayed water on the headers. Left, inside header wasn't as hot as the other 3.

Then after it had been off for a few minutes, I got a couple drips.

All this for changing the throttle cable.

35 year old motorcycles are like that. They need almost constant maintenance.

How much rust in the tank?

And how long since the last time you adjusted the valves?

No rust in the tank.
I've not adjusted the valves. I realize it's probably needed. However, I'm from the troubleshooting belief that if something works, and then you change something, and then it doesn't work, it has to be the thing you changed that caused the problem. I know that's not always correct, but it just makes sense.

I forgot to add, I did pull the spark plug, and it was blackened (brand new last year), but with the excess fuel going through there, I'd imagine it would be a little caked up.

You may be correct that the problem is not directly related to the valves, I just hope you aren't one of those guys that doesn't do maintenance until something goes wrong is all. Failing to adjust the valves causes not only running issues but it also seriously compromises the durability of the engine since the valves will hang open and burn.

Good luck

The valves are the first thing to check. It takes time and money to do so they are neglected until the bike won't run anymore. By that time it's too late. If a guy refuses to do this, there's no point in helping him. :whistle:
Steve

I am doing maintenance. I've been lucky in that this bike hasn't really needed any service other than wearables. I just rebuilt the front calipers with new internals, lines. The rear is next. I want to do the valves, probably the clutch, wheel bearings, neck bearings.

But first I need to get it to stop leaking gas.

I had a similar problem on my kz550, are you using fuel with ethanol content? I found that ethanol fuel can cause leaks from one or more carbs, usually just one carb, I have changed all needles and seats, still did it, if you try clean ethanol free fuel, see how that goes, in UK it's hard to get clean fuel, so I put an in line tap to solve the problem

Yes, all of our fuel is 10% ethanol. I use the green Stabil ethanol formula treatment.

Another problem with ethanol fuel is it melts the inside of older rubber fuel lines, if your on 10% ethanol, change your lines to ethanol proof modern ones, the melted rubber gums up the cars.

Between school ending and two-thirds of my kids in baseball, the bike has just sat.
The carbs are on without the air box boots. I wanted to let it idle for a bit and see if there would be more drips.
This morning I pulled the left two plugs just to compare them, then put them back.

I start the bike with the choke and it immediately back fires. I start it again and after a few seconds on choke, I switch it off and let it idle. Idle started to get choppy so I put the choke back on. Idle evened out and after about two minutes of idle, it back fired twice and shut off.

How do I go from a bike that runs great and needs a throttle cable, to a bike with a leaking carb, then the carb more or less fixes itself, and now back firing?

This is too much of a swing to be coincidence.

A thought just occurred to me. Would gasoline in the motor oil cause a backfire?
Since I had gas pouring from every hole, it's possible some got into the engine oil.
I'll change it this after noon if I can find an oil filter locally.

To test for bad float valves: remove carbs, remove bowls, lay carbs upside down. Put fuel line in your mouth and gently blow air into it. Listen for air coming from carbs. Lift floats one by one to identify who is leaking and who is not by the back pressure you can feel in your mouth.

If the leak comes back, I'll certainly try this.

Right now I need to figure out the backfiring.

Tomorrow I will change the oil and filter, and put new plugs in. I'll also reattach the air box.

And see what happens.