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TOPIC: Re:Firing on one cylinder
#1020002
Paladin (User)
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Gender: Male cwayneb.com Location: Lexington, KY Birthdate: 1954-10-09
Firing on one cylinder 4 Months ago  
I mostly hang out on the RSR Forum but need some help so I thought I'd try here too. I'm getting a lot of good suggestions there but thought someone here might have some different ideas. I've tried looking around for threads on this topic, but don't seem to find any, which is odd because there are a number of threads on it in the RSR Forum. So I must be missing them here.
I was out riding a couple weeks ago when my '02 RS backfired a couple times as I was pulling up to a stop and it died. After about 15 minutes of trying, I finally got it started again, but it was only firing on the rear cylinder. Since then I've put Seafoam in the gas tank - no help. I put brand new plugs in - no help. I've ohm-ed out the coils and plug wire boots - no help (they're all within specs). Intake manifold does have two cracks but I've sealed them with RTV sealant and they don't appear to go all the way through anyway. This weekend I plan on ohm-ing out the pickup coil to make sure that's ok. I've also got a known good used CDI box coming to try out. I've checked in the dark to see if my coils are arc-ing to the frame and they don't appear to be, although I think I've gotten shocked a few times over the years when my knee has touched my billet air filter cover. (So I'm still looking into the possibility of arc-ing.) I do have good spark going to the front cylinder. I'm assuming fuel and air are getting there since both cylinders are fed by the one carb and the rear cylinder is firing fine. I do also have compression to the front cylinder and my decompression solenoid seems to be working properly. When I rev the motor, it is backfiring about every 3rd stroke. Doesn't backfire when idling. Any ideas/suggestions are greatly appreciated,

Wayne
 
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#1020005
davej (User)
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Re:Firing on one cylinder 4 Months ago  
You may not understand my answer but check for oil pressure. That is 1 of the syptoms for a broken oil pump drive gear that your year bike had issues with..
 
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#1020017
Paladin (User)
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Re:Firing on one cylinder 4 Months ago  
davej wrote:
You may not understand my answer but check for oil pressure. That is 1 of the syptoms for a broken oil pump drive gear that your year bike had issues with..

Thanks Dave. I've been told that a way to check and see if that was the problem if you don't have a way to check the pressure is to remove the oil dipstick and start the bike. If oil splashes out the pump is working. If it doesn't, you've got the broken oil pump shaft. With mine, the oil splashes. I don't actually have a way to test the oil pressure otherwise. Any suggestions on where I might find a gauge and where/how I would connect it? Thanks again!
 
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#1020019
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Re:Firing on one cylinder 4 Months ago  
+1 on possible oil pump shaft fail. You'll probably want to know how to check the oil pressure also. Try loosening the banjo bolts on your oil lines some and start the engine. Have some rags handy.
 
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#1020021
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Re:Firing on one cylinder 4 Months ago  
Ctkog wrote:
+1 on possible oil pump shaft fail. You'll probably want to know how to check the oil pressure also. Try loosening the banjo bolts on your oil lines some and start the engine. Have some rags handy.

OK, will do. so I'm assuming if the oil barely trickles out I've got a problem but if it really pumps out I'm ok.... - thanks!!
 
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#1020022
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Re:Firing on one cylinder 4 Months ago  
Start the motor, and crack one of the banjo bolts loose on the chrome Y on the left side of the bike. If your not getting oil flow, then you know its the oil pump drive gear shaft.


Yes. If the oil pump drive gear shaft is good, you'll have lots of oil flow.
 
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Last Edit: 2017/08/16 20:58 By SKWEARpeg.
 
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#1020023
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Re:Firing on one cylinder 4 Months ago  
SKWEARpeg wrote:
Start the motor, and crack one of the banjo bolts loose on the chrome Y on the left side of the bike. If your not getting oil flow, then you know its the oil pump drive gear shaft.


Yes. If the oil pump drive gear shaft is good, you'll have lots of oil flow.



+1 ....
 
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#1020032
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Re:Firing on one cylinder 4 Months ago  
OK, thanks!
 
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#1020033
Shores (User)
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Re:Firing on one cylinder 4 Months ago  
Is SVS not a possible cause?
 
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#1020037
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Re:Firing on one cylinder 4 Months ago  
Shores wrote:
Is SVS not a possible cause?

I would think so, I've also heard you guys mention checking the AIS head port caps to see if one has fallen off or come loose.

It'll be interesting to see if his oil pressure and coils etc check out.
 
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