TOPIC:

Long time no see guys!

Long story short, I bought my 77 KZ900 a few years ago, made an account on here...sold it to a guy in VA about a year after...then bought it back from him a few weeks ago.

Super excited to have it back. Should have never sold it. Won't happen again.

So, on the test ride the bike ran amazing. Didn't choke or stutter, it ran beautifully. Trailered it 3 hours and took it for a quick spin when I got home. It was breaking up some mid to full throttle. The carbs were leaking a little and he said it probably needed to be cleaned up, so I thought maybe that was it. He included a full carb rebuild kit so I took them off and did that. Set the float heights, bench synced them, and slapped them back on. Threw new plugs in, new plug wires and fired it up. Wasn't running right. Sounded down 1 or 2 cylinders. After troubleshooting it, come to find out cylinders 1 and 4 are intermittently firing. Ohm'ed out the Dyna 3.0 ohm coils and they both check out at around 3.5 each. So I did the plug test against the block and sure enough 1 and 4 were barely firing any spark. Went in and traced all the wiring for breaks or damage and didn't see any, but replaced and made newer "better" connections where I saw fit. Tried again and same results.

Finally...my question is...could the timing have jumped loose on the pick ups or what else can I troubleshoot before I just buy a whole brand new Dyna kit? Should I start from scratch and reset the timing? I researched and found out it looks like I have the Dynatek Dyna III kit. Is this an older cheaper kit? Should I just upgrade with a brand new kit or do you think I can figure this old sucker out? I feel like I can revive this ol'girl with this kit, but I just want to do it right. HELP!

Thanks guys,

-Tom from Maryland

Did you check the resistance on the secondary side of the coils? Should be around 13,500 ohms.

Just researched how to do that and will do that as soon as I get home and report back. Don't know how I missed that tidbit in my research! Thank you!

I’d love to see some pictures... I have a 1977 A5??? frame I’m trying to authenticate... is the 77 an urban legend?

I don’t think the dyna III is correct... maybe a Dyna 2000 if it has a blue breaker plate

I'll try and get some updated pics up soon!

It does have the blue mounting plate and I also thought it might have been the Dyna 2000, but it runs to a small black box that has Dyna 000 printed on it which I've found out is the Dyna III (D35-1) kit that has a blue mounting plate as well. Wonder if the little black box (don't know what it's called) has partially failed??

Would the Dyna S be a good replacement? Just wondering if I should just go ahead and replace it all anyway...

Yes, the Dyna III was the predecessor to the Dyna S. The Dyna S will replace the Dyna III pickups and the box, so you will have a tiny bit of rewiring to do.

Its possible for the Dyna III to fail, but you should swap parts around to confirm its the Dyna and not something else like coils or wiring. Low voltage at the coil can cause that symptom.

Most Dyna ignitions fail with total loss of spark on one pair of plugs, so partial loss is odd.

loudhvx wrote: Yes, the Dyna III was the predecessor to the Dyna S. The Dyna S will replace the Dyna III pickups and the box, so you will have a tiny bit of rewiring to do.

Its possible for the Dyna III to fail, but you should swap parts around to confirm its the Dyna and not something else like coils or wiring. Low voltage at the coil can cause that symptom.

Most Dyna ignitions fail with total loss of spark on one pair of plugs, so partial loss is odd.

I couldn’t find anything showing application for the dyna III for the 900... thank you

loudhvx wrote: Yes, the Dyna III was the predecessor to the Dyna S. The Dyna S will replace the Dyna III pickups and the box, so you will have a tiny bit of rewiring to do.

Its possible for the Dyna III to fail, but you should swap parts around to confirm its the Dyna and not something else like coils or wiring. Low voltage at the coil can cause that symptom.

Most Dyna ignitions fail with total loss of spark on one pair of plugs, so partial loss is odd.

Appreciate that. So I'll do the secondary coil test and swap some parts around to see if it follows. When I say partially....1 and 4 would spark but only on the initial bump of the starter I guess. I'll do it again to confirm when it actually sparks...

So, if my coils come back good, then all I'd need to buy is the Dyna S DS2-1 and wire them directly to my good coils and cutoff switch wiring, correct? There's one on eBay for $118, but I have no issues spending the $275 for a whole new kit if it'll fix this running issue. That way I know I have some fresh components and not some old worn out bits in there.

EDIT: I'll also snap some pics of the components that are on my bike and maybe some of you can confirm what it has? It was running great when I owned it a few years ago and even before I just took the carbs off to rebuild them. Coincidence that it just happened to crap out now though?? Oh well...

Not an urban legend Mikaw. I have a 77 900

BOOM_FIST, have you checked the voltage to the coil primary....

Here’s a easy solution and provides future proofing.

www.wgcarbs.com/index.php/using-joomla/e...-categories/89-coils

Mikaw wrote: BOOM_FIST, have you checked the voltage to the coil primary....

Here’s a easy solution and provides future proofing.

www.wgcarbs.com/index.php/using-joomla/e...-categories/89-coils

The link you posted isn't working for me.

I did do the primary test which resulted in 3.5 ohms on both coils. I will be doing the secondary coils when I get home. Is this what you meant?

Here is the docs for dynatek for the dnya 111