Welcome, Guest
Username: Password: Remember me
  • Page:
  • 1
  • 2

TOPIC: KZ440 Won't Start After Top End Rebuild

KZ440 Won't Start After Top End Rebuild 23 Jan 2019 19:21 #797393

  • Jaytraeg
  • Jaytraeg's Avatar Topic Author
  • Offline
  • Member
  • Member
  • Posts: 32
  • Thank you received: 1
Hey all, here's the story so far:

My bike (1981 KZ440 LTD) was burning oil, so I took off the head and cylinder block to see what was going on. On inspection, the piston rings looked fine, the cylinders were a little glazed, and the valve stem seals looked fine. I had the cylinders honed, reused the rings, replaced the valve stem seals and all gaskets that were taken off with new ones. I made sure the bore and roundness were both in usable range, and reassembled completely according to the manual found on this website. Now, the bike won't start at all! It cranks, but no popping/banging/coughing like it even wants to start, even with starting fluid right in the cylinders.

Things to note:
-I didn't mess with the timing advancer except for setting the cylinders to TDC
-Valves were gapped to spec after reassembly
-Spark is good and strong
-Plugs are wet/smell like gas
-Oil was changed after rebuild
-Tried switching plug wires, but no change
-Battery was charged to full juice and is in good condition
-Gas is fresh, and carbs have gas in the bowls (plus were cleaned very thoroughly during the rebuild process)
-Looking in the spark plug holes while cranking, the valves are opening and closing smoothly

I'm stumped! Any ideas?
1981 KZ440 LTD

Please Log in or Create an account to join the conversation.

KZ440 Won't Start After Top End Rebuild 24 Jan 2019 00:52 #797411

  • Nebr_Rex
  • Nebr_Rex's Avatar
  • Offline
  • Member
  • Member
  • Posts: 1635
  • Thank you received: 216
What is your cranking compression?
2002 ZRX1200R
81 GPz1100
79 KZ1000st daily ride
79 KZ1000mk2 prodject
78 KZ650sr
78 KZ650b
81 KZ750e
80 KZ750ltd
77 KZ400/440 cafe project
76 KZ400/440 Fuel Injected

www.dotheton.com/forum/index.php?topic=39120.0


.

Please Log in or Create an account to join the conversation.

KZ440 Won't Start After Top End Rebuild 24 Jan 2019 12:06 #797439

  • Jaytraeg
  • Jaytraeg's Avatar Topic Author
  • Offline
  • Member
  • Member
  • Posts: 32
  • Thank you received: 1
I don't know, haven't checked it yet. My compression tester is in another city at the moment (I'm at school), but the next time I go up I'll make sure to grab it. Anything else I can look for in the mean time?
1981 KZ440 LTD

Please Log in or Create an account to join the conversation.

KZ440 Won't Start After Top End Rebuild 24 Jan 2019 18:04 #797447

  • baldy110
  • baldy110's Avatar
  • Offline
  • Member
  • Member
  • Posts: 1937
  • Thank you received: 332
Pull a plug out use your finger to plug the sparkplug hole. Open the throttle all the way. If you can't keep your finger on the hole while cranking then you have enough compression to start it.

Please Log in or Create an account to join the conversation.

KZ440 Won't Start After Top End Rebuild 25 Jan 2019 11:34 #797493

  • loudhvx
  • loudhvx's Avatar
  • Offline
  • Sustaining Member
  • Sustaining Member
  • Posts: 9478
  • Thank you received: 1047
There could be something in this thread below, coincidentally very similar situation.
www.kzrider.com/forum/2-engine/609860-kz...fter-rebuild?start=0

Please Log in or Create an account to join the conversation.

Last edit: by loudhvx.

KZ440 Won't Start After Top End Rebuild 25 Jan 2019 12:45 #797498

  • Jaytraeg
  • Jaytraeg's Avatar Topic Author
  • Offline
  • Member
  • Member
  • Posts: 32
  • Thank you received: 1
Thanks for the suggestion, baldy, I'll give it a go. I'm pretty sure the compression should be at least enough to get the darn thing to give me something. And thanks for the link to that other thread, loudhvx! I couldn't really follow a lot of the jargon about timing, but it seems like my bike is acting very similarly to the OP of that thread. How would I go about checking if my timing is off? Like I said, I didn't mess with the advancer during the rebuild and I triple checked that the cam was timed correctly according to the manual, but it sounds like it might have gotten 180 degrees off somehow? Thanks for the help all.
1981 KZ440 LTD

Please Log in or Create an account to join the conversation.

KZ440 Won't Start After Top End Rebuild 25 Jan 2019 20:12 #797529

  • OldguyJoe
  • OldguyJoe's Avatar
  • Offline
  • Member
  • Member
  • Posts: 40
  • Thank you received: 6
Hi Jay.
OP of the other thread here.
I just tonight found time to install the new coil, but the kids are sleeping and it's -11° outside, so a test run has to wait till morning.
Will gladly update you on the results.
Further, if you didn't remove the advancer or timing rotor during the rebuild, you don't have to worry about the 180° reversal thing.
Joe
1977 weird Canadian version of KZ400-s3
Had a 1973 Kawi 175 F3 trail bike in the 80s.

Please Log in or Create an account to join the conversation.

Last edit: by OldguyJoe.

KZ440 Won't Start After Top End Rebuild 26 Jan 2019 12:55 #797567

  • OldguyJoe
  • OldguyJoe's Avatar
  • Offline
  • Member
  • Member
  • Posts: 40
  • Thank you received: 6
My engine started up with the new coil.
Who knows what went wrong with the old one, as the engine ran great before the rebuild. Perhaps it had just enough oomph to spark with low compression.
Anyhow, I had good luck ordering the coil from this site's advertiser. I don't know which one you'd need, but surely someone here does.
Best of luck.
1977 weird Canadian version of KZ400-s3
Had a 1973 Kawi 175 F3 trail bike in the 80s.

Please Log in or Create an account to join the conversation.

Last edit: by loudhvx.

KZ440 Won't Start After Top End Rebuild 26 Jan 2019 13:09 #797572

  • loudhvx
  • loudhvx's Avatar
  • Offline
  • Sustaining Member
  • Sustaining Member
  • Posts: 9478
  • Thank you received: 1047
Thanks for the update Joe. 30+ year old coils are the only thing that ever got me stranded, so I usually don't trust them even if they pass a spark test, like yours did. I just hate to tell someone to spend money and not have that fix the problem. I'm glad it did in your case.

Jaytraeg's bike would use the same coil as you since you probably have a 440 or 750 twin ignition.

Please Log in or Create an account to join the conversation.

KZ440 Won't Start After Top End Rebuild 26 Jan 2019 13:11 #797573

  • Jaytraeg
  • Jaytraeg's Avatar Topic Author
  • Offline
  • Member
  • Member
  • Posts: 32
  • Thank you received: 1
I'm happy to hear that, Joe. Congratulations on your new working motorcycle!
Now I forget, did you say that your old coil still had an ohm reading that was considered within spec according to the manual? If so, how did you go about diagnosing the coil as faulty? That part of the thread was a little confusing to me.
In an case, looks like I'm going to spend part of the evening doing a resistance check on my coil. Thanks for the leads, guys!
1981 KZ440 LTD

Please Log in or Create an account to join the conversation.

Last edit: by Jaytraeg.

KZ440 Won't Start After Top End Rebuild 26 Jan 2019 16:40 #797604

  • loudhvx
  • loudhvx's Avatar
  • Offline
  • Sustaining Member
  • Sustaining Member
  • Posts: 9478
  • Thank you received: 1047

Jaytraeg wrote: I'm happy to hear that, Joe. Congratulations on your new working motorcycle!
Now I forget, did you say that your old coil still had an ohm reading that was considered within spec according to the manual? If so, how did you go about diagnosing the coil as faulty? That part of the thread was a little confusing to me.
In an case, looks like I'm going to spend part of the evening doing a resistance check on my coil. Thanks for the leads, guys!


I don't mean to answer for Joe, as he is perfectly capable, but as I understand it, he was getting good spark at the plugs in open air tests whenever he was kicking the motor over. But when he was doing long-spark tests by placing the plug bodies about 1/2" apart, he was just barely able to get spark. That does indicate a weakness in the coil or igniter (coil is more likely to fail), but it should have still been enough to start a normal motor, especially on ether. Perhaps it was a combination of a weak coil and low compression making it difficult to start?

I normally spray ether into the carbs so the ether only gets carried in with air, and is atomized.
The following user(s) said Thank You: Jaytraeg

Please Log in or Create an account to join the conversation.

Last edit: by loudhvx.

KZ440 Won't Start After Top End Rebuild 26 Jan 2019 20:55 #797655

  • Jaytraeg
  • Jaytraeg's Avatar Topic Author
  • Offline
  • Member
  • Member
  • Posts: 32
  • Thank you received: 1
Alright, I ran a few tests and this is what I found out.:
The primary winding resistance (resistance between the two power terminals on the coil) measured at 2.0 ohms, which is out of the usable range specified in the service manual (3.2-4.8 ohms)
The secondary winding resistance (resistance between the two spark plug wires) measured at 11.3k ohms, which is in range of the 10.4k-15.6k ohm usable limit.
I think this is enough to condemn the coil, so I'll get a new one ordered. On the Z1 website, it says that using a coil with a slightly higher resistance is better than using one of slightly lower resistance (which I'm assuming is referring to the spec for the primary winding resistance listed above), so I'm thinking about getting the 5 ohm Dyna coil they have.
1981 KZ440 LTD

Please Log in or Create an account to join the conversation.

KZ440 Won't Start After Top End Rebuild 26 Jan 2019 22:04 #797659

  • loudhvx
  • loudhvx's Avatar
  • Offline
  • Sustaining Member
  • Sustaining Member
  • Posts: 9478
  • Thank you received: 1047

Jaytraeg wrote: Alright, I ran a few tests and this is what I found out.:
The primary winding resistance (resistance between the two power terminals on the coil) measured at 2.0 ohms, which is out of the usable range specified in the service manual (3.2-4.8 ohms)
The secondary winding resistance (resistance between the two spark plug wires) measured at 11.3k ohms, which is in range of the 10.4k-15.6k ohm usable limit.
I think this is enough to condemn the coil, so I'll get a new one ordered. On the Z1 website, it says that using a coil with a slightly higher resistance is better than using one of slightly lower resistance (which I'm assuming is referring to the spec for the primary winding resistance listed above), so I'm thinking about getting the 5 ohm Dyna coil they have.


3.2 to 4.8 ohms would be for points. Does your bike have a points ignition? I assumed all 440's had electronic ignition, but I could be mistaken.
If you have the factory electronic ignition you would want the 2.2 ohm gray Dyna coil or 2.3 ohm factory coil. A 3 ohm coil (Dyna green coil) would probably work as well, and that can be used with a Dyna S if you found a way to modify an inline-four Dyna S for the Kz440.

Please Log in or Create an account to join the conversation.

KZ440 Won't Start After Top End Rebuild 27 Jan 2019 08:02 #797687

  • Jaytraeg
  • Jaytraeg's Avatar Topic Author
  • Offline
  • Member
  • Member
  • Posts: 32
  • Thank you received: 1
Ah, you're right. I just noticed the supplemental content at the end of the service manual for the 1981+ 440's, and the usable range is 1.8-2.8 ohms for the transistor type (which mine is). Looks like it's still in the usable range for that, then. I'll take a page out of your book hvx and replace it anyway, because it does look like the original coil. Will report back with the results when the coil comes in.
1981 KZ440 LTD

Please Log in or Create an account to join the conversation.

KZ440 Won't Start After Top End Rebuild 07 Feb 2019 19:26 #798335

  • Jaytraeg
  • Jaytraeg's Avatar Topic Author
  • Offline
  • Member
  • Member
  • Posts: 32
  • Thank you received: 1
Alrighty, after the coil came in I had to wait to install it because it required different fittings for the spark plugs to connect.
So finally, after installing the new coil and fittings and new wires to boot... nothing. The bike still turns over, and it has a really strong blue spark, but it still refuses to so much as pop.
I'm really truly stumped and a little disheartened. The bike has good compression, good spark, good fuel, a freshly recharged battery and good air. I've tried starting it with the kickstand up, but that didn't help, nor did starting fluid. The pistons are moving up and down in the cylinders, and (as far as I can see) everything is in good working order. New oil, too.

Any ideas folks?
1981 KZ440 LTD

Please Log in or Create an account to join the conversation.

KZ440 Won't Start After Top End Rebuild 07 Feb 2019 19:55 #798336

  • OldguyJoe
  • OldguyJoe's Avatar
  • Offline
  • Member
  • Member
  • Posts: 40
  • Thank you received: 6
Real headscratcher there.
After putting on my new coil, it took a few dozen kicks for it to come to life. I was getting disheartened too.
Do you have a starter, or is it kick-only? Hopefully the former.
Much luck.
1977 weird Canadian version of KZ400-s3
Had a 1973 Kawi 175 F3 trail bike in the 80s.

Please Log in or Create an account to join the conversation.

KZ440 Won't Start After Top End Rebuild 07 Feb 2019 20:12 #798338

  • Jaytraeg
  • Jaytraeg's Avatar Topic Author
  • Offline
  • Member
  • Member
  • Posts: 32
  • Thank you received: 1
Actually, it's electric only. I really wish I had a kick-starter, so that I could just go at it instead of wearing down the battery like no tomorrow.
Say Joe, do you know what kind of rhythm your spark plugs spark with? Now that I think about it, my sparks were kinda doing a dupple, heartbeat -esque pattern instead of the steady rhythm I would have expected. Is it supposed to be this sort of pattern?
1981 KZ440 LTD

Please Log in or Create an account to join the conversation.

KZ440 Won't Start After Top End Rebuild 08 Feb 2019 16:01 #798369

  • OldguyJoe
  • OldguyJoe's Avatar
  • Offline
  • Member
  • Member
  • Posts: 40
  • Thank you received: 6
My plugs spark evenly. The 400 sparks at the same time in both cylinders, with pistions 180º opposed, using a single coil with dual outputs. Same for you?
Does your bike have points or transistor ignition? There must be a way to check the igniter if it's the latter.
1977 weird Canadian version of KZ400-s3
Had a 1973 Kawi 175 F3 trail bike in the 80s.

Please Log in or Create an account to join the conversation.

KZ440 Won't Start After Top End Rebuild 08 Feb 2019 18:42 #798370

  • Jaytraeg
  • Jaytraeg's Avatar Topic Author
  • Offline
  • Member
  • Member
  • Posts: 32
  • Thank you received: 1
Now there's a thought.
From what I gather, the 400's and 440's are very closely related engines and should have the same crank angle. My bike is one that has the transistor ignition, so I went and resistance tested the igniter and found that it's pretty much trash (failed 5/6 tests). Any suggestions on where to find a replacement one?
Also, I resistance checked the pickup coil just for kicks and it was good.
1981 KZ440 LTD

Please Log in or Create an account to join the conversation.

KZ440 Won't Start After Top End Rebuild 09 Feb 2019 07:05 #798385

  • Nebr_Rex
  • Nebr_Rex's Avatar
  • Offline
  • Member
  • Member
  • Posts: 1635
  • Thank you received: 216
1] The KZ400/440 have 360* cranks.
2] Hw did you have a nice blue spark I the ignitor failed?
3] The KZ440 ignitor will be harder to find than the units used on the 4 cylinder models.
If a stock ignitor is unavailable the 4 cylinder can be spliced in. The pickup coil wires are paired up
red and yellow or blue and black. Or you can go retro and revert back to points which are more common.


.
2002 ZRX1200R
81 GPz1100
79 KZ1000st daily ride
79 KZ1000mk2 prodject
78 KZ650sr
78 KZ650b
81 KZ750e
80 KZ750ltd
77 KZ400/440 cafe project
76 KZ400/440 Fuel Injected

www.dotheton.com/forum/index.php?topic=39120.0


.

Please Log in or Create an account to join the conversation.

  • Page:
  • 1
  • 2
Powered by Kunena Forum