Dynatek Coils

Ugh.

Took the carbs off, cleaned them and still pipes 3 and 4 are cold. Spark plug wires are new, as are the boots. 
I tested the dynacoil and got good readings. A friend said that coils can still fail even when you test them. Has this ever happened to anyone? Bike is a 1977 KZ650 Kawasaki.

 

One coil supplies plugs 1 and 4, the other supplies plugs 2 and 3 so unlikely to be both coils on one side only.
Are plugs 3 and 4 wet or dry after trying to start it? 

The plugs are dry. Could it be valves?

No, if the plugs are dry it's definately carbs. 
It ran before you parked it up for a few months and then didn't. Valves are mechanical so nothing has changed. 
Does it back fire when trying to start it? If it does are you sure you have not accidently put the plug caps on the wrong cylinders.

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No, if the plugs are dry it's definately carbs. 
It ran before you parked it up for a few months and then didn't. Valves are mechanical so nothing has changed. 
Does it back fire when trying to start it? If it does are you sure you have not accidently put the plug caps on the wrong cylinders.


 

Yes, it backfires when it first starts.

How it happened.

I took it on a long run in july, parked until october. Took it for a ride and could hear It wasnt getting full power. Pipes 1,2 3, were hot, but not 4. Checked plug 4 and it was covered in oil. changed it. Then the bike ran good for 2 miles. Parked it. Started it 2 days later,  really started running poorly and then pipe 3 started running cold. Now it only runs on 1 and 2.

If it ran when you changed the plugs then that's where the issue is likely to lie.
DO NOT buy plugs from ebay or amazon as there are many fakes which are a total waste of money. 
Only use plugs from a known quality supplier. Most fakes are ngk but denso plugs are faked also but not as much.
Try swopping plug 4 with plug 1 and plug 2  with plug 3 and see if the problem moves with the plugs or remains with the cylinders. 

If the plug oiled whilst stood it's likely the valve stem seals.

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If the plug oiled whilst stood it's likely the valve stem seals.
 

that would cause backfiring? the plugs arent oily anymore

wrote:

wrote:

If the plug oiled whilst stood it's likely the valve stem seals.

 

that would cause backfiring? the plugs arent oily anymore

Yes! It causes plug fouling which leads to intermittent firing or no firing at all until either the engine gets hot or you clean or change the plug which you say you did.
Even once the oil has burnt off it can leave oil varnishing on the center electrodes porceline which will allow the spark to track to earth at low rpms rather than jump the gap.
Also unburnt fuel from a misfiring cylinder builds up in the exhaust and is then ignited by by outgoing combustion from another which will cause banging from the exhaust.

CTD!!!

Reading this and many other post i have to say again as i have before,the knowledge on this forum is outstanding.You guys are great!! Hence the reason im a sustaining member for life.