TOPIC:

Nduetime wrote: ...In terms of the spark at the points. Early on, I managed to pull the plugs out and ground them to the motor to check for spark. Hard to properly do by oneself, in the middle of the summer afternoon, using the kickstart....

With a wasted spark system, if the plug wires are long enough, may ground the plug bases to each other to achieve continuity throughout the secondary loop, which is same as allowing the plug bases to be connected via contact with the engine head.



Good Fortune!

That's not what I was talking about. Basic trouble shooting procedure with a point system is to check if there is arching at the points. That is a indicator of bad condensers and or points. Some sparking the bike will run bad, a lot, it won't run at all. In the video I heard the starter make a noise when it didn't start. Does it work? Does the battery?
1. If the battery is bad, it will tax the system to the point of low voltage to the ignition system.
2. A shorted battery can destroy the rectifier allowing A/C voltage in the system making it impossible for the D/C components to work properly.
When I was wrenching and a customer came in with a bike with a bad battery, refused to buy a new one, I sent him home with the bike.
There are a lot of people who will cheerfully sell you special tools whether they are needed or not to fix the problem. Also it is tempting to hop around trying to find the problem or just buy everything used. I call this the Shot Gun approach. Used parts can be bad too, that's why they are so cheap.
One thing at a time. These are balanced systems. If one component is weak or not working, the whole system will be effected.
Dirt bikes typically have two separate systems. Ignition and lighting/charging. They don't need a battery to run.
If it has a starter, it needs a good battery.
Steve

swest is correct about your bike needing a good battery.

This is especially true of your KZ400-D4 because it has a field coil type generator. Bikes with field coil generators (like my KZ650-C1) don't want to start or run if they have a bad battery. Ed

Batteries can be very expensive. I bought one at AZ for $80. It didn't even last a year. The warranty was only 90 days. I found a seller on Ebay, Battery Solutions and got one for $35 plus shipping and a one year warranty. I bought it but it was much smaller than the one I had. I called them and they sent the right one for $5 more. They didn't want the one they sent me because it had acid in it. I sold it on CL for $25. I highly and do recommend them.
Steve

I'm on my phone right now so I'll try to address all question from memory. If I miss something just mention it.

So I recently purchased a new, full (proper) size battery from the shop I mentioned in the first post. Old battery was very small and inefficient.

At one point months ago (with old battery,) I couldn't get the bike to start off the starter. I managed to take it out and clean it per a video I watched on YouTube. I reassembled and hooked up battery directly to starter via jumper cables. In doing so, I managed to see that the starter would spin. However, it would not start from the button. Two things here... First, I knew battery was insufficient. Second, since it was just the starter and I was trying to nail down the compression ready to check the status of the motor, I decided the electric start problem could be addressed later once everything else was taken care of. I assumed the electric start was more of a luxury, since I can easily start the bike on the first or second kick. I have tested the relay and it test out fine. At some point I had pressed the starter button and could hear some fuzzy/pop sound but nothing more (certainly not a good thing...most likely burnt wires, no?) With new battery, I now get no sound/click or anything when I now press the button.

I had misread the comment/question regarding the spark (assuming you had meant spark to plug.) I have not pulled the cover off to check if I'm getting spark at points. Check that...I might have but I can't remember. It's something I'll do though.

Coil is new and I have a new rectifier but have not tacked that quite yet. I verified I had proper float height and that I was getting fuel flow through both carbs while bike was running.

The reason I decided to go back to the valve clearance is because although it was something I had checked when I first got the bike, I was unsure if I had done it properly. After struggling with everything I decided it was wiser to follow the service manual and listen/read others suggestion of rechecking and verifying the basics to carefully eliminate those important things. In this particular case, I decided to start with the valve clearance.

Think that might cover it all, but if not please remind me.

I know I seem kinda harsh. Just call it the "Spock" in me. It looks like you're going by the numbers. That's good. The electrical's mean as much as all the rest. Balance. Install them and other issues will become evident. Keep it up.
Steve

Alright, rain finally subsided enough for me to get out and work on my bike.

I started first by checking valve clearance again, this time with motion pro feeler gauges. Didn't have to adjust them any. But this brings up a question. Spin crank until right piston drops and rises to TDC. Continue till indicator is aligned with T. Check measurements on right cylinder. Spin one full rotation to recheck. This next part I'm unsure about. From here do I spin one more full rotation for TDC and alignment of T for left side? The reason I'm a a little confused is because both pistons are at TDC at the same time. Is there any reason I could check and adjust both right and left at same time?

After I verified and rechecked both sides I replace my condenser and points with new ones.
Then I set points gap per service manual. Then moved to setting timing. It seemed that no matter what I did, I couldn't get the points to open just after F mark. It wanted to open later. I said f it and decided to loosen both points and points plate at same time in order to adjust them enough to get me closer. Managed to get points to open just after F and then checked points gap. Adjusted the gap and recheck it. Then moved back to timing to verify points opening at F.went back to verify point gap and then timing. Even went and rechecked valve clearance.

I kicked the bike over and started the bike. Idle around 3k. After about 2 minutes twist the throttle and get it to drop down to about 1200 after release. A few more twist and the bike revs and drops back to ~ 1000-1200. Then died.

Tried to restart and again, could only get it started with throttle. But bike won't maintain idle without throttle. Can only get it to about 800 RPM's with 1/2-full throttle and runs rough, dies upon full release of throttle.
So new condenser and points haven't improved condition. There's no sparking coming from the points area. Looking for ideas again. Tomorrow I'm gonna recheck points gap, timing and valve clearance again, provided the weather permits. Going to recheck float height again and check plugs.

I went back and read your OP... sorry, didn't read the other 4 pages.

You mentioned the coil was not stock. Did you address this yet?
Have you replaced it with a stock, or aftermarket coil for your bike yet?

May also need a good carb cleaning?

The coil had been replaced with a new aftermarket unit. Also, carbs were thoroughly cleaned when I rebuilt them.

This still sounds like a fuel supply issue to me, but tell us more about this:

"Can only get it to about 800 RPM's with 1/2-full throttle"

If you give it more throttle at this point does it die? Or do the RPMs go up? Also, what's going on with the choke through all this?

So when the bike needs throttle to keep running (once bike has initially died and then restarted,) I have to keep on the throttle. I refer to this as being in "limp mode". It requires about 1/3 throttle and minutely runs better (say in increase of ~50-100 RPM's,) as I reach full throttle. Once I start to release the throttle back to idle it just dies once I get to less than 1/3 throttle (working off memory on this last part.)
This whole time there is no choke involved. Bike initial start is usually after second kick, requiring no choke at all. If I use the choke, RPM's increase. This adds to the trouble of getting the bikes RPM's down. Once the bike dies, choke doesn't really help to get bike started (I can only accomplish a start by engaging the throttle at the same time as I kick over.) When in this "limp mode", if I engage the choke (while maintaining throttle,) the bike just dies.

Recheck your pilot jets.