dmaxx
Member
What is the standard compression in lbs for Vipers?
daman
New member
Should be around/ (PTO)128-130/(CENTER)142-144/(MAG)142-144.
Mtnviper
Member
Most Vipers (stock) are 110-115 mag, 125-130 ctr, mag measured at sea level on cold engine.
journeyman
Active member
Mine is 128/144/145
daman
New member
Mtnviper said:
Thos are some low numbers....
viperken
New member
I checked two vipers with low miles (1600 +/-) and the PTO was 115, center 125 and Mag 125 PSI. These readings were taking when the engine was warm.
Don't forget not all compression testers read the same. Some get weaker over the years.
Don't forget not all compression testers read the same. Some get weaker over the years.
daman
New member
viperken said:
Hmmmm.....really,, ok then i've never seen one that low stock.
Mtnviper
Member
There have been multiple post's on this subject, 110-115, 125-130 is a common reading. I have checked the compression every year on mine since it was new. It's always been in that range using different tester's, or a least untill I pulled two layer's out of the head gasket. Then add 10 psi to those reading's! 
journeyman
Active member
I have two testers and both mine read the same. I always check on a cold engine with the throttle pulled open.
tunme
New member
- Joined
- Mar 2, 2005
- Messages
- 24
from the day it was new pto 116,center 126,mag 124
2 years old,2800 miles removed center layer of gasket and gained 11 psi
more than readings above.
2 years old,2800 miles removed center layer of gasket and gained 11 psi
more than readings above.
dmaxx
Member
I just checked both of mine on a cold engine with screw in compression tester, not a cheap one. Both read 118 pto, 125 center and mag. One sled has 8000 miles and the other 2500.
Srxspec
Your #1 performance shop!
journeyman, we know you've got a good runnin one!!!
I've probably checked 20-30 Vipers since they've come out in 2002. On average they have ranged from 110 (pto), 125 (center), 125 (mag) on the low side to 125 (pto), 140 (center), 140 (mag).
I've probably checked 20-30 Vipers since they've come out in 2002. On average they have ranged from 110 (pto), 125 (center), 125 (mag) on the low side to 125 (pto), 140 (center), 140 (mag).
journeyman
Active member
Funny thing is my Dad's is a hair quicker than mine. His compression is 130/145/145......just a hair better than mine. Before I piped it (and burned it down) my numbers were not as good as his. I had around 125/138/139. Then of course ,I got it rebuilt with new pitsons, rings and two new cylinders...OUCH!!$$$....and now it is stronger than it was originally. Go figure.
mine 4000kms original no engine mods and 130 pto 142 center 145 mag.
Damn thing should blown about 4 times by now
1. folded over carb boot(damn dealer drove before i noticed 1500km)
2. fliped on side and didn't burp oil line ( olny had 50 km on it)
3. Filled the hood full of snow and was sucking water through the carbs enough ti trip the check engine light on an 02
4. lent it to my bro and he did # 3 again even worse(iced up the carbs with carb heat on
Damn thing still go's, best sled ever built imo.
Damn thing should blown about 4 times by now
1. folded over carb boot(damn dealer drove before i noticed 1500km)
2. fliped on side and didn't burp oil line ( olny had 50 km on it)
3. Filled the hood full of snow and was sucking water through the carbs enough ti trip the check engine light on an 02
4. lent it to my bro and he did # 3 again even worse(iced up the carbs with carb heat on
Damn thing still go's, best sled ever built imo.
journeyman
Active member
Well if you have those #'s kirkswim , it's very close to mine. I assume it's a runner. Mine runs with or beats 800 twins. I have raced one F7 and beat it handily, and it also runs with all my buddy's RX-1's. I can't complain about that I guess. Now an APEX.....forget it.