Dynas Ignition on old KZ1000C2

I have a 1979 KZ1000C2 Police bike. In the Clymner Book it sounds like some were points & condensor and some were electronic systems. I think the Dynas system in mine is an add-on. Clymer says primary coil resistance xhould be about 4.0 ohms on contact point models and about 1.5 ohms on transistorized models. My Dynas coils read 3.0.

3 out of 4 plugs get carbon fouled, fuel/air mixture could be too rich, plug heat range too cold (I use NKG B8ES), dirty air clnr (mine's new), faulty automatic choke (mine's manual), excessive idling, or weak ignition.

I know compression is low in the 3 problematic cylinders. I just did the Marvel Mystery Oil top end treatment in case there are gummed rings and have Sea Foamed the carbs. The jury is still out on the results.

I don't hear the "snap" in the spark so I figure the problem could be weak ignition. Does high resistance at the coil primary point to that?

Thanks!
KZ

To the best of my knowledge, it's always been a given that early factory C1-C1A-C2s were all points-based. Kaw came out with factory EDIs in '80 on the C3s, or so I thought...

If you've got a Dyna, it was an add-on.

The low compression can be a number of things; valve adjustment, valve seats and rings top the list. That can be having a big bearing on your plug readings.

Despite all the ad hooey, "Mystery Oils" and fuel additves and carb sprays are NO substitute for plain 'ole gettin' in there and gettin' your hands dirty. I myself wish things were different, but it just ain't so.

You didn't say how "low" low compression was, so it's problematic to get a handle on causes...

The NGK B8ES plug is OEM spec for that motor; going to a hotter plug should not only not be necessary - it could be a mistake.

On the cheap(est) but effective fixes list, I'd start with three things:

1. Adjust the valves.

2. Dig up Wired George's coil mod in the file section and do it - it'll liven up the spark.

3. Do an old-fashioned carb cleaning. Again, Wired George has a tutorial or 10 lying around between his posts and the files section - and his own web site that's uber-much more than a passing fancy. He's a spiffy resource and every word he types can save you $$ - sooner OR later...

Hope that helps.

Post edited by: Pterosaur, at: 2006/05/21 12:56

Thank you for the input. Here's the results of compression tests after the top end "over-night soak" and about 15 miles on the bike.

(cyl#)dry/wet:

(1)110/115
(2) 70/90
(3)125/150
(4) 95/120

Signs point to new rings. Valve seating may be weakest on no. 1. Any other observations?

Thanks Much!
KZPoncho

kzponcho wrote:

Signs point to new rings. Valve seating may be weakest on no. 1. Any other observations?

Thanks Much!
KZPoncho

Well, we never got around to how many miles are on the motor, how much smoke its blowing and when - i.e., continuously, on start up then diminishing, loud banging noises coming from the cases, etc...

And another topic is what you want to accomplish - the range on that runs from just getting it running to putt around with all the way up to a full-blown restoration.

If you just want to boat around, and as-is, she smokes a little cold but it peters out as she warms up, get the valves adjusted and clean the carbs first. See what that does for the numbers 1&2&4 pots. If they all get into the #120+ range, you'd be surprised how long that motor will run like that. It won't outrun much, but if that isn't the plan and your tree-hugging sensibilities (and the local EPA's...) aren't offended by a little smoke - have at. Keep a spare set of plugs handy, an eye on the oil level and go ride.

Rebuild/restoration jobs get more complex and go up in price rapidly with the depth of the job. Doing a top end with OEM parts will likely cost you upwards of $1500, and that's if you do most of the work yourself short of cylinder boring and valve grinding.

Get into the lower end, and you can spend major pesos as well. It's a matter of what your goals are and how deep your pockets get...

You're welcome...

You asked for advice and got almost the perfect advice. Before rebuilding the engine, you had best check valve clearances. THIS IS THE MOST COMMON REASON FOR LOW COMPRESSION other than a bike just sitting and the rings bound up. Personally, I think a compress check and then checking the valve clearances on an older bike the MOST important first step to getting it to run right. If ignored and you try and work from other directions; either carbs or electrical, you are WASTING YOUR TIME!!! If the valves are OK, THEN ask about going to the next step.

Valves seem to be OK in the .05mm to .15mm range. I took another compression reading "dry" just for the record:

cyl/compression: Clearance: intake/exhaust
1/122.5 .13mm/.06mm
2/112.5 .10mm/.13mm
3/118.0 .10mm/.13mm
4/118.0 .10mm/.10mm

I've got 39,491 on the odometer and don't see much smoke in the exhaust. Spark plugs show dry carbon buildup.

Thanks for any insight.

Poncho

Hats Off to Wired George!! I read through your article on wiring power to coils direct from battery. A nice strong blue snap at the plugs & my old KZ1000-C2 never ran better, even with some low compression issues. I'm going to try .032 gap and see if I notice a change and if plugs keep from fowling.

Thanks for giving me some ride time before I retire it and tear it down for a top job this winter.

Yours with gratitude,

KZPoncho

Glad it helped... the longer I hang around here the more I am convinced that half the carb problems are poor spark or lack of valve clearance (affecting compression adversely!). Get some riding in...

The compression isn't really all that terrible. When you did the dry/wet test, the difference wasn't really that dramatic. You might want to consider doing another dry/wet to benchmark compression issues relative to the rings. If you do suspect ring seal, keep in mind that the clearance between piston and cylinder bore becomes critical when there is too much of it. Putting a new set of rings on pistons that have too much piston-to-bore clearance is a waste of time. At that point, you are better off buying a newer used eBay block/piston set and install it with new rings (hone too) OR bite the bullet and install new oversized pistons. I am not convinced that new/oversized pistons actualy work any better than a used set that are within spec but this is just a personal opinion and lots of folks can make a good argument for buying new stuff.