TOPIC:

Hello folks! The engine fires up on my 1974 KZ400, but dies immediately. My sense is that it's not getting gas - I try to give it some throttle and nothing happens. This is the same whether I use the kick or electric start. I don't know that this might have anything to do with it, but I have some weird power draw issue, in that my brand new battery dies even after riding it around. Last night I charged it fully, and this morning it was totally dead. My mechanic ordered a different battery and I am waiting for it to come in. But I don't think this is a battery issue, as until last night it fired up on the first or second kick. This is my first bike with manual clutch, I am a woman, not mechanically inclined, and am renowned for my lack of common sense (my brothers and dad enjoy reminding me of the time I asked about oiling my squeaky brakes). So don't hesitate to laugh at any current or forthcoming dumb questions or assumptions! I spent a fortune, waited two months, finally re-learned how to ride using a clutch - and kick-start the bike, and am now utterly despondent that it isn't starting. Any assistance will be GREATLY appreciated! (And yes, there's gas in the tank and it's on)

You may have an issue with the charging system. The charging system will keep the bike running once it is started and it will hopefully charge the battery as well.
Do you have a voltmeter?

A voltmeter would definitely help in this diagnosis. It sounds like you have a short somewhere or a bad connection. Without a voltmeter,  you can check wiring for any obvious frayed wires or loose connections. Start at the battery and follow the big wires looking for anyplace it comes in contact with anything and seeing if the insulation around the wire has rubbed through. Also check every connection by unplugging and plugging back in paying attention that sometimes the connector has become loose. It would be obvious when you pushed on it first before you tried to pull it apart and it clicks into place or feels like it wasn't completely plugged in. Also... VERY  IMPORTANT...disconnect the negative battery terminal before checking all these connections and wires. Some connectors, especially that have multiple wires going to them click into place with plastic tabs. You have to squeeze on them in a certain position to release the plastic tab to pull them apart. If you're uncomfortable doing this, visually inspect every connection for corrosion or any signs of rust or anything else. You'll need to take the bikes, gas tank, and side panels off to see most of the wiring. At a minimum take the side panels off. That's where most of your connections are going to be but there are some under the gas tank.

coranmbeck73 wrote:

My sense is that it's not getting gas - I try to give it some throttle and nothing happens. ...

...my brand new battery dies even after riding it around. ...

...until last night it fired up on the first or second kick. ...
 

Clarity please, on conflicting statements:
"...even after riding it around. ..."  implies it has been successfully ridden.  Can we assume it ran well at the time?  If so, retracing steps between then & failure to run could help.

We personally don't know KZ400's well at all, but it hails from the same era as our '73 through '75 Z1's.  They have three positions on the ignition switch; OFF, RUN and PK (parking).  The PK position illuminates only the tail light, and the key can be removed in the Pk position.  It's easy to miss the tail light being on if one doesn't walk behind the bike & look, and the tail light will drain the battery over night.  We've done it.  Perhaps the ignition was inadvertantly left in Pk position?

Troubleshooting bikes can be challenging using text based means such as forums.  Appreciate that you're willing to learn not only to ride, but also to learn your bike hands-on.  We can help you get through this.  Just resist becoming discouraged as best you can.

The Lovely Z1BEBE sez 'Hi! Nice to see another woman here!'.

Good Ridin'
slmjim & Z1BEBE

OK, you have to understand how carburetors work to understand why what your doing with the throttle is the opposite to what you need to do to start a carburated engine. 
When the piston goes down on the fuel intake stroke it creates a vacuum which with the inlet valve open creates a vacuum in the engine side of the carburetor throat. It is this vacuum which draws fuel up through the pilot circuit and the enricher circuit. 
If you open the throttle the carburetor  slides are raised thus allowing air to be drawn into the carburetor throats which reduces the vacuum and leans off any mixture entering the cylinder making it harder to start. 

 

No offense but It might be so simple that the bike is lean and you forgot  to put the choke on or if you have to little gas in the tank and must set the fuel petcock to reserve ,but that does not explain the draining battery issue.Anyway welcome to the forum ! Good luck !

A clogged tank cap vent create a vaccum that restricted the fuel flow to the carbs.

I recently saw a Youtube video of a bike having this same problem. The guy found the jets were clean, but passageways clogged. He cleaned them and the bike ran perfect afterwards. Might be worth a look.

Ummm, I think I may have a voltmeter- if not, I have a friend who most definitely can bring one over for me!

I did consider this, and it's certainly a possibility, but I took the bike to a shop that specializes in 70s Japanese bikes, and they did a TON of work - including cleaning carbs, replacing carb boots, jets, etc. I finally did talk to my mechanic, and he says replacing the battery with a different one (which is on the way) should work. It just seems odd that I'd been able to kickstart it right up and now it simply won't. 

Haha - I will never take offense and would ANY day prefer a problem I'm having is due solely to my own incompetence (or inexperience). The tank is full of (new) gas, and I don't ever use the choke(s) as I live in Southern/Central California. I had asked my mechanic if I needed to do so and he said no. So I'll definitely try it! (I have tried starting it with the peacock set to reserve, on, off - no dice. What I haven't done - but will today - is try a bit of starter fluid in the carbs to check if it's a fuel issue). Thank you! (I just realized I didn't say thank you in my two previous replies to members. Sorry about that - I am so VERY grateful for any and all advice - THANK YOU!!!

Thank you. I do not know what a tank cap is, but I will immediately find out and do some investigating! Presumably this is something I can resolve myself, no?