Kz1100 will not start despite all signs normal

newOld_kz1000 wrote: With a fixed amount of vacuum created by the engine, a 'choke' normally reduces the amount of air allowed to enter so that the *ratio* of fuel rises in the fuel/air mixture. I don't think you meant "it adds fuel", I think you meant "it enrichens the fuel/air mixture, achieving this by reducing the amount of air in that mixture, by reducing the amount of air allowed in from the airbox, thus increasing the percentage of fuel in the fuel/air mixture."

So I'm back to "why is there no enrichment happening when I reduce air from the airbox, why doesn't the percentage of gas in the fuel/air mixture rise."

Then again, I'm missing something about this carb model. I don't have a shop manual for the bike, and the parts list I have doesn't give a model identifier.

I think you are missing something and I told you what is was. I think your carbs have an enricher and not a choke. The thing you're calling a choke is in fact an enricher that does indeed add fuel and doesn't affect air flow at all period full stop.

The enrichner circuit does not restrict air, it opens an additional fuel circuit that increases fuel flow for starting. Since there does not seem to be any fuel flowing through the low speed circuit or the enrichener circuit, I'd say the circuits are still clogged.

TexasKZ wrote: The enrichner circuit does not restrict air, it opens an additional fuel circuit that increases fuel flow for starting. Since there does not seem to be any fuel flowing through the low speed circuit or the enrichener circuit, I'd say the circuits are still clogged.

Like I said -- "there's a quirk about this carb model I'm not aware of."

And that's that quirk. I was expecting an air-reduction choke.

I noticed a brass shaft in each carb drop down from the ceiling of the float bowl area of the carb body, and right into the float bowl.

This brass tube was long enough to be immersed in the fuel resting in the float bowl.

I'm now thinking that might be this enrichener mechanism's fuel supply source? I thought it was an overflow. And maybe it is, I won't know until you guys confirm this new guess I have here. Again, I don't have a manual for this bike or even a Clymers to explain it.

If that brass tube is in fact the 'fuel enrichener's supply line for gas -- where is the final output for this gas? I'm guessing somewhere in the throat of the carb? But I didn't see an exit hole anywhere,

Then again I wasn't looking for one either.

Use a guitar string to clean out the pilots. At the bottom of the bowl is a shaft the choke siphon tube fits in. The tube has a small hole at the bottom. The shaft often has a small jet at the bottom and a opening leading to the fuel. Clean them too and spray choke cleaner through them.
Steve
kzrider.com/forum/11-projects/598262-kz-...-will-it-live#672882

swest wrote: Use a guitar string to clean out the pilots. At the bottom of the bowl is a shaft the choke siphon tube fits in. The tube has a small hole at the bottom. The shaft often has a small jet at the bottom and a opening leading to the fuel. Clean them too and spray choke cleaner through them.
Steve
kzrider.com/forum/11-projects/598262-kz-...-will-it-live#672882

Okay, thanks Steve and thanks all for your patience, Carbs coming back off tomorrow. I did notice a small hole at the bottom of that tube I mistaked for an overflow. I wire-brushed that opening. "Okay the hole is visible, close enough for government work, it's an overflow tube."

My first career was lead guitarist in rock bands, I still play, and I did in fact use my carb cleaner .011 high E string a bit -- pushed it into the tiny hole in that 'fuel enrichener' tube, not very far, "it's an overflow, that's the least of my worries right now."

First time I've had a problem caused by a 'fuel enrichener' mechanism. I've probably worked on carbs with fuel enricheners before, but never had a problem with them that forced learning about them. I had a blind spot in my working knowledge there, and I thank everyone for putting me on the right track.

Started looking for details/explanation on how the carb's "fuel enrichener" system works.

Maybe most people on the board know this already, god knows my experience is that of a garage tinkerer, but I thought if someone else reads this thread this diagram I found would help -- it seems to show how gas gets from that brass tube immersed in the float bowl into the engine intake -- that was a question I still had about all this. Hope this helps someone else. The 'side pull' lever in the diagram below to engage the 'choke' (fuel enrichener) is identical to what's on my ZN1100 carbs, and the diagram below is also specifically for CV carbs.

I suspect the pilot circuits are imperfectly clean.





I also suspect the enrichener circuits are imperfectly clean.








I'm uncertain about whether these diagrams are an exact match for the carbs at hand, but will hopefully be close enough to help.

Good Fortune!

Thanks Patton -- nice of you to provide those diagrams, it demystifies the situation -- I'm pretty confident after I follow these suggestions she'll fire right up -- thanks. I'll need this to locate the enrichener circuit port -- I didn't even look for it when I had the carbs off yesterday.

TexasKZ wrote: The enrichner circuit does not restrict air, it opens an additional fuel circuit that increases fuel flow for starting. Since there does not seem to be any fuel flowing through the low speed circuit or the enrichener circuit, I'd say the circuits are still clogged.

I concur with that and also when using said enrichener, DO NOT give it any throttle or it defeats the purpose.

Barry2 wrote:

TexasKZ wrote: The enrichner circuit does not restrict air, it opens an additional fuel circuit that increases fuel flow for starting. Since there does not seem to be any fuel flowing through the low speed circuit or the enrichener circuit, I'd say the circuits are still clogged.

I concur with that and also when using said enrichener, DO NOT give it any throttle or it defeats the purpose.

When using the enrich system, if the engine wants to start, but won't keep running...does that mean it is not getting enough fuel, or too much?
If the engine starts on the first crank, mine usually needs throttling to keep it running for the first ten seconds or so, before the idle begins to smooth out. But quite often it refuses to start on the first attempt :pinch:
And if it doesn't start on the very-first attempt, then the enrichener seems to become useless after that. Then it's crank, crank...sputter-stall, wait, crank...bang! Then v-room!!!

UPDATE. Finally got some time to pull the carbs again.

Once I took off the very first float bowl, I paid careful attention to that brass tube with the tiny hole in the end of it -- this tube hangs downward from the ceiling of the float bowl chamber.

Well, that brass tube actually *slides completely inside* a deep shaft that is drilled into the rim of the float bowl.
So when the carbs are all assembled, that brass tube is completely shut off from the float bowl chamber, it's completely enveloped by that deep shaft.

EXCEPT.

Except when I shined a flashlight down that shaft in the rim of the float bowl -- there is a brass 'jet' at the bottom.
And that brass jet leads to a hole at the inside bottom of the float bowl. That deep shaft is directly connected to the gas at the bottom of the bowl, by way of that hole.

I sprayed carb cleaner, using the red straw on the aerosol can, down that deep shaft with the brass 'jet' at the bottom.
The carb cleaner should have flowed through that brass jet at the bottom of the shaft, and into the float bowl through the hole I mentioned above.

NOTHING.

So I used a guitar string, patience, carb cleaner, and 120psi freaking compressed air! and finally got the blockage cleared. Now, when I spray carb cleaner down the shaft, it spills into the bottom of the float bolt through that (previously blocked) hole.

And that's why the enrichener wasn't working.

I sure wish they'd stuck with a traditional choke. Why make a 'start up' system more complicated. Simpler is better.

Pictures to come.

Did you clean them all. It's a better system.
Steve