TOPIC:

Hi All,  been working through this bike and need some help.  It was bought new by my dad, driven 1500 miles and then parked.  I've recently got my hands on it and decided to clean it up and get it running again.  I'm at the point now where trying to start it up, and it won't.   I do have the service manual and have been going through that. 

Here's what i've done. 

Fuel/Air:  Carbs pulled apart and run through ultrasonic. All jets and components hand cleaned and cleared out with compressed air. Carb actually looks very good, so i left most of the original components and just replaced seals and o-rings.  Checked the float level and that's fine.  Carb bowls drain nicely and fill from the tank.    I did have to clean the gas tank with vinegar, flushed it out a few times with gas.  All new fuel line from the tank down.  Cleaned the petcock as well.  Fuel system from tank down has been gone through. 

Compression:  140psi engine cold.  I can feel the difference turning engine over by hand with plugs in and out

Spark:  New plugs, new condensers (tried a few different ones). Readjusted the gap on the points. Was a little tight so i opened it up a bit per the manual's spec. I checked resistance on coils, and they are in spec. Testing the spark plugs against the head, i get a nice fat spark on each plug.  I do see a blue spark on the points during crank.  I swapped the coil wires around just to cross that off as well. They really dont' reach the opposite cylinder so i'm sure the firing order is right.  The original plugs seemed to be fouled which is curious. I barely got a spark out of them, which is why i replaced them. 

Timing:  Used the manual and went through a basic timing check to see if the points began to open when the flywheel timing mark aligned with pointer. It does.  It's close enough that I figured i should get something to ignite. 

Battery: Brand new, and on a charge in between my crank attempts. 

I get no fire at all.  Not even an attempt to fire. No misfire or backfire.  I can smell gas if i crank with plugs out, so i'm confident the carbs are putting fuel in.   I've gone as far as to spray brake cleaner and gas into the cylinder to try to get something out of it, but nothing at all. 

The curious thing was when i got my hands on the bike, the spark plugs were hand-tight and fouled.  Not sure if someone was messing with it, or the bike was parked with a problem.  My dad passed the bike around to a few brothers, so nobody remembers why it was parked 30+ years ago in the mid 80s. 

I might pull the carbs apart again and check to see that i put them together correctly. I feel like i've gone through the ignition pretty well, but the fact i don't get it to fire on brake cleaner and gas makes me suspicious. (i'll grab some starter fluid this afternoon).   I dont suspect any mechanical issues as i can see the valves opening and closing and have good compression.   

Ideas?  Thoughts on what to try? 

 

Maybe the wires that tell the coils to fire are switched?  

Thought about that.  Checked the wiring against the wiring diagram and the colors all match to how they should be routed, but i can't recall if i ever swapped them around and tried cranking it.  I'll give that a shot.   At this point, i'm going back to recheck everything I did. 

If you have fuel, ignition and compression then the only other factor is timing, if you are 100% happy that the ignition timing is correct have you (just for "peace of mind") checked the camshaft timing ?

You said in you first post you had a fat spark so it's safe to say your coils are fine. Get a can of starting fluid and rule out fuel delivery issues.
The can of brake clean I have here says it's not flammable.

Some additional random thoughts.

You have a much better chance of success if you set the timing right. You can use a small 12v bulb, a bit of wire and a crocodile clip to find where the points just start to open and set to the timing mark. Manual should have details.

Small spark at points is probably ok but big snappy one is a sign of failing condensor of maybe points. Sparking can cause pitting on the point surface. I have gently run a small file across point surface. I know you replaced condensors.

Dont know what carb or carbs you have. Cleaning you really have to poke each jet and passageway with a guitar string or brush bristle to make sure they are clear..
You carb will have either a choke flap/butterfly which restricts air intake or an enricher which when operated lets more gas into the cylinder. Make sure whatever you have is working.

If the above is good then put 4 or 5 cc of oil in each cylinder , put in the plugs and wait 5 or 10 minutes for the oil to seep down around the piston rings. This will maximise compression when you try to start. Give a squirt of starter fluid in the airbox and have at it.

As a last resort - and not everyone might recommend this - twist and hold the throttle fully open and  try again but be prepared to ease off as if it starts then the engine will race.

good luck

Try disconnecting the + wires from the coils and run a wire directly from the battery + to the coils, and see if it will fire. Don't leave it connected like that too long. If it does start, you will have to pull the wire to shut it off.
On my kz305, I was having to crank the engine for a long time before it would start. With the jumper wire attached, it starts on first crank.
Power from the battery to the coils needs to pass through a fuse/fuse holder, ignition switch, kill switch, and all the associated connectors. I'll be going through all that stuff, cleaning switch contacts, and all connectors.

All good ideas.  I need to start over so even though I did a lot of what was suggested, it obviosuly isn't working so I need to go back and double and triple check.  Thanks for the suggestions. 

Going to pick up some real starter fluid on my drive home from work.  I will feel better if i can get it to at least fire once. That will give me some direction. 

Won't fix your problem but you'll want a fuel filter inline before too long

ckahleer wrote:

Try disconnecting the + wires from the coils and run a wire directly from the battery + to the coils, and see if it will fire. Don't leave it connected like that too long. If it does start, you will have to pull the wire to shut it off.
On my kz305, I was having to crank the engine for a long time before it would start. With the jumper wire attached, it starts on first crank.
Power from the battery to the coils needs to pass through a fuse/fuse holder, ignition switch, kill switch, and all the associated connectors. I'll be going through all that stuff, cleaning switch contacts, and all connectors.

In essence what you are talking about is a by-pass relay mod (wired George relay) see the below for the rational

www.kzrider.com/forum/4-electrical/61751...-pass-relay-w#866367

It is possible that some PO did set the advancer cam lob 180 degree off !?!?

 

Update. 

picked up some starter fluid on the ride home.  It took a few tries, but it lit off!  After repeating two or three times I was finally able to get it to idle. 

it doesn’t run well….but it runs.  It gasps and stalls when I give it throttle, and the tach doesn’t read correctly, but I can work with this. 

looks like it’s now a carb issue….but it’s alive! 


thabks for all the suggestions, sorry it was just something simple.  


edit:  a little more run time and It was running much better.  Took it around the block.  Drives nice!   However it struggles to go up in RPM so I’ll need to pull the carbs again and go through them or spring for a proper rebuild kit vs cleaning. 

need to fix the tach.  Seems to stick to 2k rpm
and not respond