I got this 1995 f3 with 45k miles running after it's definitely been sitting for some time. It had issues with flooding before, and as a result the oil was way overfilled due to mixture of gasoline and oil.
I've cleaned the carburetor but believe there may be a vacuum leak somewhere, since when I blip the throttle it likes to hang around 2k rpms. When I start the bike, it idles higher then comes down with no choke. Adding choke kills the bike, so maybe it is still running rich? I can't really tell. The plugs are still very dark.
It's worth noting I haven't run it up to temps yet. The smoke doesn't smell sweet per se like I would expect from burning coolant, the closest I could describe it to is like wallpaper paint.
Looking at the oil and coolant, everything looks fine. No bubbling at the radiator, and the oil looked fine (other than being like 50% gasoline) when I changed it out.

My next steps I plan are to clean the carbs again, this time I'll replace the boots I might have damaged them when pulling them off for the 2nd time, see if that fixes the hanging idle.

Here's what the gas looks like coming out of the fuel pump... I drained the tank as best I could and added fresh gas in thinking it would be diluted enough to be clean but I guess not. Also, the first time I fired it up, I'm guessing a combination of crud in the old fuel lines and fuel pump clogged the floats before I cleaned them out again.

 

Did you fix what caused flooding and richness initially?

- leaking petcock
- non-factory jet sizes
- non-sealing float valves in carbs

Until you fix those, bike will continue to flood and run rich.

 

A vacuum leak is often shown by an erratic idle. In the video, your idle sounds pretty constant.

Assuming everything else is correct with the carbs, (though I suspect that isn’t the case given the smoke), a hesitation when you blip the throttle is often indicative of carbs that are out of sync.

But as I said above, and by dano, focus on clearing up the unburnt fuel issue and that will get you pointed in the right direction.

 

yup, originally the flooding issue was caused by the floats being clogged up from sitting. I've since cleaned the carbs and there's no more leaking anywhere.

As far as I can tell the jets are original. I haven't adjusted the pilot screws or synced the carbs, was hoping the settings from when it last ran should be 'close enough'

I am just worried because usually, white smoke is indicative of HG failure and if that's the case not much sense in continuing the project.

I guess since other than the smoke it's not showing any other signs of HG failure I'll sync the carbs and see if there's any improvement. Thanks for the help

 

When you cleaned the carbs, what was the process you used?
The reason I ask is because anytime this bikes sit without being properly prepped for long term storage, a thorough cleaning is required as the many ports and such get clogged very quickly.

 

1. remove pilot and main jet from each carburetor, blow carb cleaner thru them and compressed air until all the holes are clear and crisp (including the sideways ones)
- the brass jets were rusty so I put them in vinegar for a short time to clear up the rust
- blow thru all the other holes in the carb with the floats removed with cleaner + air
2. replace the float valve and clean the float seat with brasso and then vinegar to remove some of the rust.
3. blow the air holes adjacent to where the velocity stacks go with carb cleaner and compressed air
4. wipe the CV slides clean, inspect the cv slide rubber for holes/cracks

 

Do compression test next (leakdown better).

There’s a lot more that can be done with carbs. But not worth effort if engine’s got blown headgasket.

 

Worried about losing the adapter in the spark plug hole so I only turned it in two rotations...

I got 150, 125, 145, 140 psi from 1-4, going to try a valve job to see if that helps anything

Done cold, no air filter and WOT

 

Yeah, I red Loctite adapters to end of compression-gauge hose.

That #2 looks suspicious. If it’s worn rings, that might allow enough blowby through to cause that smoking.

 

update, bike stopped smoking. I did the valve clearances, cleaned the carburetor again (2 and 3 main jets had a little crud in them), switched out the boots.

When I put it together it was running great, but now the ide isn't steady again. It'll start up, then after maybe 10-15 seconds the idle will drop a bit, and then if I try to set the idle back up it'll often overshoot into 2k+ and hang there. Same thing if i blip the throttle. If I then let off the idle adjustment screw itll drop down low and almost die.

I can ride it around but after coming to a stop the idle will drop real low.

I think it's an issue with the carb boots and clamps I used. I couldn't find reasonably priced new oem boots so I bought k&l boots that said fits cbr f2, and 95/96 f3 (I have 95 f3). The carb side of the boot won't sit flat, looking around the forums seems some people said f3 boots are longer than f2 boots? I used the original carb clamps and since the screw won't fit on i admittedly basically screwed around and used a zip tie to tighten it up :/. Engine side sits just fine.