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not running right?

Posted: Sun Feb 25, 2018 6:31 pm
by yamahoper
I bought my 1984 RZ500 about 1 year ago. It had been neglected and hadn't run in a couple years. With some help here I got it running and thought it should have more power. I was happy to have the bike start well and put a set of chambers on it. Last month I decided to run some gas through it and it seemed like it was running on 3 cylinders. The lower left chamber was cold so I changed out the plug and no difference. Today I went a little deeper and checked for spark on both bottom cylinders and it looked good. I fired it up and it seemed to be idling ok but the lower left was cold and no smoke so i pulled the plug wire and no change in the idle. I pulled the coil and switched the plug wires around so I could reach the right side with the short wire. I fired it up and pulled the left wire and no change pulled the other and it dropped to 2 cylinders I switched the wires and only the right lower cylinder is firing. The left plug is wet so its getting fuel or could that just be oil from the injector? I tested the compression which seemed low 112 on the right and 117 on the left. Any Ideas or comments are welcome Thanks

Re: not running right?

Posted: Sun Feb 25, 2018 8:06 pm
by yamahoper
wound up being a stuck float valve. The wet plug was from the oil injection system.

Re: not running right?

Posted: Sun Feb 25, 2018 9:23 pm
by silverstrom
It is a common problem.

Re: not running right?

Posted: Sun Feb 25, 2018 10:47 pm
by yamahoper
Thanks Silverstrom, Bike is back on 4 cylinders. I'm surprised how well these run on 3 cylinders.

RZ 500 technical question

Posted: Fri Apr 06, 2018 9:14 pm
by rz ron
Hello, I’m throwing this out there to see whether anyone has experienced the same problem I am faced with. I’m having a malfunction with my RZ 500. The bike will start and seems to run fine for the first 10 minutes or so. After it warms up it seems to miss and become lethargic And will die out and not restart. I have pulled the plugs out at this point and checked for spark and there isn’t any. If you try starting it several hours later it will restart and complete the same cycle again. I’ve replaced the ignition coils and tested my stater coil which is .4 ohms. My pick up coil tested at 122.7 ohms my source coil at 162.6 homes and the other at 18.8 ohms. I’ve going through my wiring harness and all Connections seem to be clean and intact. Everything else electronically on the bike works fine. Somehow something is getting hot and opening the circuit and causing the bike not to run. I would appreciate anyone who is had this problem before to share how they resolved this problem. Thank you so much.

Re: RZ 500 technical question

Posted: Wed Apr 11, 2018 1:27 pm
by trappena
rz ron wrote:Hello, I’m throwing this out there to see whether anyone has experienced the same problem I am faced with. I’m having a malfunction with my RZ 500. The bike will start and seems to run fine for the first 10 minutes or so. After it warms up it seems to miss and become lethargic And will die out and not restart. I have pulled the plugs out at this point and checked for spark and there isn’t any. If you try starting it several hours later it will restart and complete the same cycle again. I’ve replaced the ignition coils and tested my stater coil which is .4 ohms. My pick up coil tested at 122.7 ohms my source coil at 162.6 homes and the other at 18.8 ohms. I’ve going through my wiring harness and all Connections seem to be clean and intact. Everything else electronically on the bike works fine. Somehow something is getting hot and opening the circuit and causing the bike not to run. I would appreciate anyone who is had this problem before to share how they resolved this problem. Thank you so much.
I had such a problem in the past, turned out to be vapor lock. Gas cap was not venting well.

My two cents.
Cheers.

Re: not running right?

Posted: Thu Apr 12, 2018 9:30 am
by MK
You should ask this guy as he has exactly the same problem and even the same nickname...
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