#3 cylinder backfire

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yamahoper
Posts: 38
Joined: Sun Jan 08, 2017 10:29 am
Location: Huntington Beach ca

#3 cylinder backfire

#1 Post by yamahoper » Sun Mar 12, 2017 8:47 pm

Just getting my RZ500 back on the road. Previous owner hadn't ridden it for 3 years. Seemed to be running decent after some carburetor challenges last week. I was running premix fuel and the oil injector just to be safe. Took her out for about a 10 mile ride 5 days in a row. Today I headed over to the monthly vintage bike meet after a good warm up 1 mile away bike seemed fine. After a 3-4 minute warm up, headed home and it dropped a cylinder. I checked the fuel level, didn't see any, and through a gallon in. Started right up first kick like usual sounded to be firing on all four. Went for my helmet and heard a loud pop then another with a puff of smoke from #3. I shut it down. Any Ideas, What should I do?

silverstrom
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Re: #3 cylinder backfire

#2 Post by silverstrom » Sun Mar 12, 2017 9:46 pm

Contrary to (very) popular belief, adding oil to the gas tank and running the oil pump at the same time does not give you a safer and richer mixture. In fact, it leans the mixture. The extra oil displaces gas. You should use one or the other, but not both.

If you look inside the gas tank and see no gas you have one of several problems. One is that unless you had the petcock on reserve you should not be empty. Two is that if you were on reserve you need to fill the tank as soon as possible. Number three, and most importantly, if you run out of gas you have no medium to carry injection oil and you will soon cause engine damage.

Could be a fouled plug from the excess oil. That would be simple. It could be crud from the gas tank plugging the pilot jet in #3. Not an uncommon problem. That would be an easy fix. It could be something more sinister. Start with simple and see how that goes.

yamahoper
Posts: 38
Joined: Sun Jan 08, 2017 10:29 am
Location: Huntington Beach ca

Re: #3 cylinder backfire

#3 Post by yamahoper » Sun Mar 12, 2017 10:33 pm

Sorry correction , #1 cylinder. I forgot the exhaust crosses under the seat... ROOKIE . Realized it after I put a new plug in #3 with no change , Started to see how I could switch the plug wires. Read that suggestion in a thread here. Anyway put the new plug in #1 that was soaking wet and black. Back on all four and running good as before. I think its time to get off the premix.

yamahoper
Posts: 38
Joined: Sun Jan 08, 2017 10:29 am
Location: Huntington Beach ca

Re: #3 cylinder backfire

#4 Post by yamahoper » Sun Mar 12, 2017 10:40 pm

Thanks silverstrom , You have been a big help. Hope to meet you someday and buy you lunch!

2002tiil
Posts: 140
Joined: Mon Jun 01, 2015 5:49 pm
Location: Veendam, the Netherlands

Re: #3 cylinder backfire

#5 Post by 2002tiil » Mon Mar 13, 2017 12:52 pm

Old spark out, turn engine (trying to clean) Try another spark and drive.
I hope you'll have more luck then i had, backfiring at my bike was a costly repair ( blow by, due to defect on piston and ring...).

As mentioned: Too much oil leans the mixture it'll run hotter

If you you here a tick or tickering, stop and dismantle. Otherwise it could cost you a crank also.

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