Viper2007
New member
Just did a top end on my viper, put new SPI teflon coated pistons in it and its doing the same thing it did before it blew the PTO cyl.
other two are brown and look to be good The PTO plug is burning a grey color, (I will try to get some pics up here)
compression is 105psi, PTO and the others are 120psi
so as far as I know the compression is still good so I have a chance to correct this without major damage
could it by any chance be a stretched rod from a previous meltdown?
checked crank seal on that side and checked the reed cage gasket as well with ether, neither increased the idle
I was running mostly midrange and idling.
i am running cpr's 155, 153.5, 153.5 and 50 pilots all across
I called hauck and they recommended 52.5 pilots so the previous owner had it jetted wrong!.,... but if the others are burning good then i can't see why just the PTO is being leaned out
-vented to atmosphere
-got opticool headgasket and rear heat exchanger as well
any help is greatly appreciated
other two are brown and look to be good The PTO plug is burning a grey color, (I will try to get some pics up here)
compression is 105psi, PTO and the others are 120psi
so as far as I know the compression is still good so I have a chance to correct this without major damage
could it by any chance be a stretched rod from a previous meltdown?
checked crank seal on that side and checked the reed cage gasket as well with ether, neither increased the idle
I was running mostly midrange and idling.
i am running cpr's 155, 153.5, 153.5 and 50 pilots all across
I called hauck and they recommended 52.5 pilots so the previous owner had it jetted wrong!.,... but if the others are burning good then i can't see why just the PTO is being leaned out
-vented to atmosphere
-got opticool headgasket and rear heat exchanger as well
any help is greatly appreciated
wheres the needles adjusted at? wheres the fuel screws? did you ever check the float level in the carbs? a better question might be what did you do to the engine in the mean time from the last burn down? just replace piston?
As mrviper suggests, what did you do to find the original problem? You need to find the cause and address it. I know this sounds like stating the obvious, but it is so often overlooked. The problem won't simply go away by throwing parts at it. We refer to this as shotgun diagnostics. Of course I guess if you replace everything, the problem will likely go away.
Viper2007
New member
the needles are at stock 3rd clip with both spacers underneath on all 3
(I corrected this problem after the meltdown, all carbs had different needle settings)
mixture screws are 2 1/2 all three
I assumed my problem occured when i ignorantly pluged in the vent line when i first bought the sled, it is now unplugged.
I was also thinking of checking my oil injection lines and port into that cylinder..?
what exactly does the grey color on the plugs mean....aluminum melting to the plug?
(I corrected this problem after the meltdown, all carbs had different needle settings)
mixture screws are 2 1/2 all three
I assumed my problem occured when i ignorantly pluged in the vent line when i first bought the sled, it is now unplugged.
I was also thinking of checking my oil injection lines and port into that cylinder..?
what exactly does the grey color on the plugs mean....aluminum melting to the plug?
Viper2007
New member
oh i also checked float levels on all three carbs and they are in spec
Bushman
New member
Grey is Bad TRUST ME 
PTO side would make me think a crank seal is leaking, I know you said you checked but still think I would look real hard @ that again. Spray starting fluid by the PTO seal while running with brake on or belt off & look for a RPM increase.
Hole in exhaust pipe?
Exhaust valve not opening? Check servo motor.
Air pocket in cooling system? Temp gun to check all three cylinder temps while running.
Real tough call from here but a few things to check.
105 comp is low & not sure if the pto seal can do that, Pull the airbox & check to make sure the needle is raising on the pto cylinder, Had a e-clip pop off once & caught it on my egt's a couple years back.
Good luck! Bushman
PTO side would make me think a crank seal is leaking, I know you said you checked but still think I would look real hard @ that again. Spray starting fluid by the PTO seal while running with brake on or belt off & look for a RPM increase.
Hole in exhaust pipe?
Exhaust valve not opening? Check servo motor.
Air pocket in cooling system? Temp gun to check all three cylinder temps while running.
Real tough call from here but a few things to check.
105 comp is low & not sure if the pto seal can do that, Pull the airbox & check to make sure the needle is raising on the pto cylinder, Had a e-clip pop off once & caught it on my egt's a couple years back.
Good luck! Bushman
I dont think the needles will be rich enuff there, I would have the clip in 4th grrove and both shims on top of the clip at least, you need fuel with cpr pipes in the midrange.
Sounds like you better pop off the primary clutch and recheck the crank seal with clutch off, start it up and spray starting fluid on the seal, see if it changes your idle rpm.
Sounds like you better pop off the primary clutch and recheck the crank seal with clutch off, start it up and spray starting fluid on the seal, see if it changes your idle rpm.
davessrx
New member
Hey if that cylinder is 105 and others 120, then your engine isn't happy again either. I was always told 10 percent between highest and lowest. It's close, but 15 psi on a 2 stroke is a lot. If its the same cylinder that melted down then there is another issue obviously. Get a can of brake clean or starting fluid. Idle it and start spraying. When the r's change you found the problem. good luck
Viper2007
New member
Crank seal has been checked, i pulled the clutch to check it already.
the viper head is cut for lower compression on the PTO side and no compression gauge reads the same, 15 psi difference is withing spec
i'll try larger pilots and the needles raised up a clip, thanks mr. viper
the viper head is cut for lower compression on the PTO side and no compression gauge reads the same, 15 psi difference is withing spec
i'll try larger pilots and the needles raised up a clip, thanks mr. viper
Would going through the carb on that cylinder to absolutely-positively make sure that its clean hurt? Maybe you might have something in one of the circuits 
, Just trying to throw an additional idea out there as stupid stuff like this happens to me. T
, Just trying to throw an additional idea out there as stupid stuff like this happens to me. T
Viperlover
New member
Sounds a little lean on the mains to me all aorund. I ran the CPR pipes on my Viper for a season with 12 mpg, and absolutely no issues. But then again, I called Jeff at CPR and got him to give me his carb specs, and I bought a primary kit from him. If I remember correctly, I ran 160/160/162.5 and 52.5 pilots. Needles were in 3rd clip, but can't rememeber off the top of my head where the washers were. Went back to stock and gave it to the wife to ride when I got the SRX.
Viper2007
New member
Think I found something that could be affecting part of my problem
I noticed the tip of the mixture screw on the PTO side carb was slightly bent... just enough to completely block off one side of the port
If the pilots were slightly lean to begin with I figure that this must be what is causing my lean mixture
I'm goin to 52.5 pilots tommorow and a new mixture screw
I will find out when I replace it tommorow
I noticed the tip of the mixture screw on the PTO side carb was slightly bent... just enough to completely block off one side of the port
If the pilots were slightly lean to begin with I figure that this must be what is causing my lean mixture
I'm goin to 52.5 pilots tommorow and a new mixture screw
I will find out when I replace it tommorow
red devil
New member
How is he running such a small main? because of vent line is pulled? Sorry for the questions but I'm trying to get my viper better fuel mileage with slp pipes don't want to go back to stock pipe. Hope you have it figured out because it sucks to burn down was with a guy last weekend on a doo and I felt bad for him.