02 Viper pto cylinder running cold

ymha700

ymha700

New member
Joined
Feb 1, 2008
Messages
59
Age
50
Location
Chesterfield, Michigan
I have a 2002 Viper that has been running sluggish and no power. It ran great last season. last weekend was the first time out this season and it was running sluggish, so i took the carbs apart and cleaned them out. rode for 8 miles and it started happening again. i brought it home drained all the fuel and cleaned the carbs and jets again. went to the cabin again this weekend and the same issues. I have the EGT gauges on it and that cylinder is running 200 degrees colder than the other 2, and if i open the throttle wide open it spits and sputters and the tem. drops in that cylinder. So i pulled the carbs out again and noticed a peice of reed in my airbox, so i pulled the reeds out and one of the carbon fiber flaps is missing, but that should not make it run that bad. I pulled the power valves out and checked and cleaned them, checked exshaust, when the power valves were out i checked the piston and rings and looked ok, but i can only see the exshaust side of piston. If i pull the plug wire off that plug while running there is no difference in sound of motor, so i then switched around the coils to see if it was that and no difference. I dont have a compression tester so have not done that yet....Any ideas of something i missed, besides pulling the jug off
 
just badly worn/chipped tipped reeds can cause running issues alone, much less a reed that has 1 of the 3 petals completely missing. your problem lies in the reeds. put new petals in and start there first.
 
Yea i was wondering about that when i found the missing reed and made a phone call to a well known yamaha peformance shop and the owner there said that one missing reed would just effect the low end. So it it possable a peice of that reed got into the cylinder and damaged the rings?
 
that carbon fiber reed chunk, that went thru the motor, caused no damage to the piston, rings, cylinders, or whatever. what reeds were you using?
 
Last edited:
ymha700 said:
I have the V force reeds
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yep, those blow for reliability/longevity. i prefer and suggest stock cages w/carbon tech petals. good luck getting them thru parts unlimited right now, as they seem to be a discontinued item.
 
I don't know about only affecting the bottom end! The reeds act as a valve to close the port & start building cly. pressure just before the piston gets above the port. with a broken petal it will want to force the fuel out to the carb & then suck it back in & on & on, creating turbulance in that port.
 
mopar1rules said:
yep, those blow for reliability/longevity. i prefer and suggest stock cages w/carbon tech petals. good luck getting them thru parts unlimited right now, as they seem to be a discontinued item.
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Which ones are discontinued the carbon techs or V force?
 
carbon techs seem to be thru parts unlimited. about 2 months ago, i ordered a set. found out their only warehouse that had 3 left in stock was the wisconsin one. the other warehouse's said something like "no longer available"....like they were discontinued. i took 2 of the 3 sets available at that time, so if you're lucky, you may be able to get that last set, if its still around. maybe you can still get them thru carbon tech themselves? i know hauck sells carbon fiber petals. i think they are just carbon techs, w/o the package.

v-force replacement petals are still available thru parts unlimited and marshall distributing too.

carbon tech site:

http://www.carbontech.com/snow/yamaha.html
 
ymha700 said:
Yea i was wondering about that when i found the missing reed and made a phone call to a well known yamaha peformance shop and the owner there said that one missing reed would just effect the low end. So it it possable a peice of that reed got into the cylinder and damaged the rings?
Click to expand...

I don't agree with this. I busted almost a whole part of a reed off and it affected my top end. Read this http://www.totallyamaha.net/forums/showthread.php?t=55860 and you'll see.
 
mopar1rules said:
carbon techs seem to be thru parts unlimited. about 2 months ago, i ordered a set. found out their only warehouse that had 3 left in stock was the wisconsin one. the other warehouse's said something like "no longer available"....like they were discontinued. i took 2 of the 3 sets available at that time, so if you're lucky, you may be able to get that last set, if its still around. maybe you can still get them thru carbon tech themselves? i know hauck sells carbon fiber petals. i think they are just carbon techs, w/o the package.

v-force replacement petals are still available thru parts unlimited and marshall distributing too.

carbon tech site:

http://www.carbontech.com/snow/yamaha.html
Click to expand...


Do the carbon techs last alot longer then the V force?
 
SXlover said:
I don't agree with this. I busted almost a whole part of a reed off and it affected my top end. Read this http://www.totallyamaha.net/forums/showthread.php?t=55860 and you'll see.
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oh exactly......what would affect a particular part of the powerband, is the stiffness/tension of the reed petal....not what is broke off the reed petal. if a petal is broke off, or chipped badly, it will affect the whole rpm range.
 
ymha700 said:
Do the carbon techs last alot longer then the V force?
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better believe it. seen it 1st hand and heard it from others too. i have a set of vforce3's on my ski-doo rev, and the 1st set went out in 800 miles. they are junk! also, the rubber intake boots were shot in 1 season too. they cracked all up, and the pto piston started to score, from a air leak starting. vforce wouldn't warranty them either. absolutly terrible. never will i buy a vforce product again.
 
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