Viper running oddly

Stetam

Stetam

New member
Joined
Mar 21, 2011
Messages
41
Age
66
Location
Jonestown, PA
Had my 2004 viper out last night and ran great when accelerating but when you let it idle down to 1500 rpms it sometimes backfired out the exhaust. I check compression this morning and 120-120 and 100 on the clutch side. What might be the problem. Carbs set rich? I had carbs cleaned recently.
 
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sounds like your running rich, causeing excess fuel in the chambers when you decell thus causeing backfire. what are your pilot jets at? a little more info on the sled would help aswell.
 
That's a 17.7% difference. Could be the problem. I know it's not a Viper, but my SRX is 130PTO 128CENTER 130MAG.
 
Stetam said:
Also went thru a quart of oil on a 20 mile ride. What ya think?
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Check if the oil cable is seated properly. If its not seated properly you will go thru a ton of oil which will start fouling the plugs which could cause the problems you are having
 
stein700sx said:
Check if the oil cable is seated properly. If its not seated properly you will go thru a ton of oil which will start fouling the plugs which could cause the problems you are having
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eggsactly^^^^^^^


also, be sure the vent hose is plugged into the airbox
 
OK, checked the compression again cold and got 110 PTO-120-120, pulled the power valves and exhaust manifold to look in the cylinders and the pistons and cylinders looked fine, like new. Pulled the oil pump to see if gear was sheared thus creating a wide open pump but that looked fine. Need to look at the oil cable adjustment today but what else could be the cause of excessive oil use? When I shut it off after a warm up all cylinders/plugs are wet with oil.

Suggestions where to go next? FWIW- it does has a handlebar riser so maybe cable issue?
 
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Your oil pump may have failed and gone to full open. However, the back-firing is likely caused by something else. Carefully check you fuel supply out including the carbs.
 
The oil pump looks fine with gears intact and seems to be working. How can it go bad when it looks fine?
 
Are the handle bar risers enough that different cables had to be put on? When longer cables are put on, then it kind of throws the stock oiler gap setting out the window. I would think most people would start out on the very liberal side to make sure there wasn't a shortage of oiling. Or the original cables are left on but are holding the oiler open. I would start shortening the gap setting to see if it starts reeling back your oil consumption. I've read on here that about 1 quart per tank is a good target...don't go any less than that.
The popping is probably from plugs starting to foul from the over oiling. I accidentally left mine slightly held open one time after having the air box off. It fouled about 3 plugs before I realized what was going on. Either that, or I would think the back-firing/popping is a lean condition because of the over oiling...less gas because of all the oil.
 
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