Constant White Fuel smelling smoke.

Hello from Australia.
I am new here and this is my first post so go easy on me.

I recently acquired 1981 z500 b1. The bike was running good for its age and condition, mostly just cosmetics. It still has enough kick in it to put a big grin on my face every now and then.
After a while I noticed that the carbs would drain out every once in a while all over the engine(Has no tubing for the drain nipple).


So being mechanically inclined I decided to take the carbs apart and find out what was causing this. I also purchased 4 carb rebuild kits for a z500, in anticipation. In the carbs I found some crap in the bowls but not much, they were mostly clean .some old o-rings which I replaced(Mainly the o-ring for the main jet). I cleaned out all the carbs with solvent and blew out all the passages with compressed air. Then reassembled them.

The rubber boots from the airbox to the carbs were mostly hardened. I managed to get the carbs reinstalled in one piece.
Put some fuel in the carbs and after a few seconds of cranking she fired right up. Initially it all looked good, no smoke out of the exhaust not completely dieing out, the bike was running a bit rough but that is to be expected the carbs were out of sync. After mabye 10-15 seconds or idling I noticed inconsistent puffs of white smoke coming out from the exhaust. It was enough to make a stream. The smoke smells completely like petrol.

The bike was mechanically sound before my venture into the carbs. Although saying I have currently only gone through the carbs on the bike and nothing else.


I have an digital FSM that I have been referencing, along with countless other KZrider forum topics
I could really use some help resolving this.

-Lewis

Is your oil contaminated with petrol? do the sniff test.

white smoke usually steam from condensation, did you use soapy water to lube the airbox rubbers?

I took the oil filler cap of and smelt it and the inside. No petrol from what I can tell.

As for the airbox rubbers I used no lubricants to get then back on, they were bone dry.

Welcome to KZR
1rst Replace your plugs , They look way rich and could be fouled.
2nd Replace the carb to head intake boots before trying to tune as you said they were dried out and they may leak air and if so you will never get the bike to run right consistently
3rd recheck everything as errors do happen
4th Are all pipes getting hot (spit test ) To see if bike is running on all cylinders.
5th Always assume bike needs a COMPLETE tuneup . As a older machine you never can tell whats worn or out of spec with out verifying conditions.
Best Wishes
Dave

The plugs in the attachments are the new ones, the old plugs were just as bad, I also had a dead plug among them.
All cylinders are firing but the exhaust headers do not heat evenly.

I think you are right about replacing the rubber boots for the carbs. I don't know how old they are but they seem to be making a good seal for now. If I had an air leak in the boots wouldn't that create a lean condition?

I have had the carbs on and off about 4 times this week, trying to resolve this, each time checking something different. I think the bike is getting too much fuel and it cant burn it all so it is going out the exhaust. The thing is I have checked all the parts on the carbs floats, jets, mains, choke. Not sure what comes next or what could cause such a rich condition. Adjusting the fuel mixture screw does nothing, it is possible the o-rings I installed on the main jets are the wrong size and they are letting fuel through?

I had intended to go through the whole bike and tune/ restore it all. I was going to checked the valve clearance after the carbs to make sure it was all in spec.

If it would help I could upload a video of the bike starting up from cold, so you have a better idea of what is happening.

Lewis

Did you run it for a while to warm it up?

Pattern Carb boots are about £40, not sure I'd replace them unless you know they are stuffed...if they have been off four times I guess you'll see if they are perished. (you got to squeeze them and look real careful -the cracks are almost invisible sometimes)

I used a pattern carb rebuild kit, but dumped the O rings and found some of my own that fitted better.
If it was chronically rich you'd get black smoke and sooty exhaust.

Seems like I didn't run it long enough. Had nice weather today. Started up the bike without a fuss and after some idling the smoke disappeared. I took the bike around the block to see how it performed and it was great. When I got back I pulled a plug to see how the engine was running. Seems to be running lean(White ash on plugs).

That's why I asked how long you run it up for. My 16 valve GSX if not started for a few weeks used to smoke quite badly but would soon clear it's throat. The valve guide oil seals were leaking slighly, when used daily it was not a problem.

White plugs is a lean condition -potentially dangerous as it causes overheating. As above, do a complete tune up, these are great bikes and a blast when you get them running nice. The slide carbs on that are quite easy totune.