viper compression check

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rodny51082

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hi, i am new to the forum and have picked up a new ride for this season! i got a 02' viper 700. i am getting it ready for this year and my buddy told me i should do a compression check on it. the bad news is i think its a little low. i did the test at WOT cold and i got 95,115,115. when i was warm it was somewhat higher 100(maybe),117,117. if i need to rebuild i want to do it now befor it turns into a problem on the trails. any thoughts?
 
also to add the sled has been moded some. tripple pipes, not sure what kind. vforce reeds clutching. not sure what else as the previous owner didnt know much about it, or so he says
 
How many miles are on it? Take head off and have a look at walls. Sounds like new piston and rings are needed before it does more damage. Walls may need honing as well.
 
You will get a thousand different answeres on this question. By the numbers you gave i say your just fine. Its not the number im looking at its seeing if your center and mag are within 5% of eachother and usually the PTO is 10-15 psi less then those. Plus if your pipped you might have a opticool headgasket on their and that will read a bit lower too as we are finding out it is thicker then OEM gasket. Every comp checker is different, everyone pulls different, ambient temps are different. Cold, warm, dry, wet, you can do it a million ways. My 2cents is use this as a baseline and check every now and then doing it the same way and watch for a change. Some guys say change rings every 3-5 thousand and some have 14 thousand and never cracked the head. These numbers you gave are pretty close to mine. I have 3 vipers with anywhere from 3000 to 5000 miles on them and my comp numbers are EXACTLY the same in all three. Now that i run opticools they are 100 - 118 - 118 exactley on all three. Hope this helps.
 
super1c said:
You will get a thousand different answeres on this question. By the numbers you gave i say your just fine. Its not the number im looking at its seeing if your center and mag are within 5% of eachother and usually the PTO is 10-15 psi less then those. Plus if your pipped you might have a opticool headgasket on their and that will read a bit lower too as we are finding out it is thicker then OEM gasket. Every comp checker is different, everyone pulls different, ambient temps are different. Cold, warm, dry, wet, you can do it a million ways. My 2cents is use this as a baseline and check every now and then doing it the same way and watch for a change. Some guys say change rings every 3-5 thousand and some have 14 thousand and never cracked the head. These numbers you gave are pretty close to mine. I have 3 vipers with anywhere from 3000 to 5000 miles on them and my comp numbers are EXACTLY the same in all three. Now that i run opticools they are 100 - 118 - 118 exactley on all three. Hope this helps.
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EGGSACTLY!!!!!!!!
;)! ;)! ;)!
 
Awesome info Super1c!! I just switched to an opticool and was starting to get worried that I screwed something up on my rebuild because my compression numbers were a little lower than I expected. Is there a way Rodny can tell if he has an opticool without pulling the head by looking at the tabs on the head gasket? BTW welcome Rodny!
 
the odometer on the sled reads 1300 miles and everything on it is super clean. looking at the head someone wrote 02 viper on the side of it with a red paint marker. not sure if this means anything but i think possible head work could have been done or maybe it has even been replaced. what is the head gasket mod you guys are talking about?
 
The Opticool is an aftermarket head gasket made by Bender. It has different hole patterns for the coolant in an attempt to even out cooling across the three cylinders. It isn't really a "Mod" as much as just an aftermarket part.

If it was me, I'd look at the plugs, pull the carbs (you're going to want to clean them anyhow) and check to be sure it is jetted properly for the pipes if necessary. As others have said, I wouldn't necessarily be afraid of the numbers, but buying a used toy is always a crap shoot and I like to go through them as much as I can before putting too many miles on.
 
I just put an Opticool in one of my vipers and my plan is to put opticools in all three. I ended up removing the center gasket of the opticool because the opticool is slightly thicker then the stock viper gasket. This is not the correct way to do this but I measured the two different thicknesses. And the opticool without the center gasket is really close to the stock viper gasket with all three gasket parts. A squish measurement is really the way to do this but this is the way I went and I ride at altitude so I really didn't want to loose any squish if I can avoid it. I do believe by installing an opticool gasket aside from the cooling factor you are also more protected from detination due to less squish.

I will say that when I was separating the opticool center gasket out, there were two brass grommets (rivit size) holding the three gaskets together. I'm not sure what color the stock viper gasket gromets are but it may be a way to tell what you have.

Hopefully I haven't messed anything up by removing that center gasket.
 
maybe i will pull the head off and have a look at it to avoid any potential problems. the price for a new head gasket is nothing compared to the ball breaking i would get from my skidoo and arctic cat ride buddies if i broke down!
 
rodny51082 said:
maybe i will pull the head off and have a look at it to avoid any potential problems. the price for a new head gasket is nothing compared to the ball breaking i would get from my skidoo and arctic cat ride buddies if i broke down!
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What kind of pipes are you running? May even sound like your head has been cut to even compression and help with cooling with pipes. Pull your carbs and let us know the jetting. This will help determine what is what with you pipes and mods. Post some pic's, sounds like a nice sled. Would love to see it. include pics of the engine and pipes! If your head is Modded you will not want to run the opticool.
 
You should be able to tell if it's an opticool gasket by looking around the outside cylinders and there's a protrusion that sticks out that's part of the gasket which holds the three gaskets together which make up the head gasket. I was just looking at a stock gasket and it doesn't have the grommet there. It just looks like it's pressed there. The opticool has the brass looking grommet on both protrusions holding the three gaskets together that make up the head gasket.

If you do pull the head make sure you drain the coolant prior unless you want a bath.
 
i checked out the head gasket and the tabs do appear to be brass like the ones in the pic newbee posted. still not sure what type of pipes it has, i dont see any name on them. i will work on getting some pics of it up. maybe someone will know what type of pipes it has from the pictures.
 
For anyone that's interested. I measured the opticool and compaired it to a stock viper gasket and this is what I got:

Stock viper (3 gaskets) = .034"
Stock opticool (3 gaskets) = .045"
Opticool with center gasket removed (2 gaskets) = .031"
 
this is my new sled. does anyone recognize the pipes that are on it?
 

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if they are speed werx are those good pipes? i would like to know what jetting to use for these too. i am at sea level to about 2000-2500 FT. what should i expect to see in the carbs when i open them up?
 
SWEDE said:
Looks likes simons cpr or the old Hauck pipes to me.
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definitley not cpr pipes. middle pipe wrapps different and single stingers on the cpr setup. i have hauck cprs on my viper. im about 99 percent sure they are speed werx pipes and im not sure on jetting myself. speed werx went out a while back. info on them is a little on the harder side to find but are still good pipes. im sure someone has the answer for ya.
 
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