Help Needed.... It runs..... But?

Well its been since September 3rd 2006 since it was last started. A 1982 KZ750R1 GPz.

Thats when the accident happened.
Here is where I'm at. It starts and idles. You can tell it is short a couple of cylinders. Carbs overhauled by local reputable shop. New petcock and all new hoses.
New Spark Plugs and Wires. No exspense spared in the rebuild. All cylinders have spark. The bike is running on 1 & 2 only. 3 & 4 are dead even though they have spark. My thoughts were coil but, 1 & 4 are on one coil and 2 & 3 are on the other. The sparks seems weaker on 3 & 4 but really can't determine if thats the issue.

I'm going to do the usual diagnosis stuff tomorrow. Compression test. Check to see if the dead cylinders spark plugs are wet.

Any thoughts appreciated. It's late and I'm going to walk away til tomorrow and think some more.

Richard Z.

Sounds like the nightmare I just figured out..my 1 and 4 weren't firing. I thought it was the coil at first. Make sure you got compression first on those two dead cylinders. Anyway, I'm not sure if it's running on all 4 at idle? If it's not running on all 4 at idle (confirm by checking exhaust pipe heat). If the two dead cylinder's pipes are cold... spray some starter fluid into your dead cylinder's carbs while bike is running and see if those cylinders come alive (pipes get hot). If they come alive, your not getting fuel. I had the same problem...a couple carb intake boots were loose and stray air/vacuum was preventing carb fuel from getting to the plugs....hope that helps....air...fuel...compression! Don

If the carbs were serviced on the "bench" then they MUST need to be synched when the bike is running .

If the carbs were serviced on the "bench" then they MUST need to be synched when the bike is running .

check your pushrods, you may have bent one.....

Figured it out.... The magnetic pickup was faulty. I had a spare and tried and well now it runs on all 4. Still plenty of carb tuning to do. I'm questioning the carb rebuild. Somethings not right with them. Very lean on the top end. And pig rich at idle.....

Richard Z.