viper compression help

S

sween741

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May 11, 2011
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35
Age
43
Location
iowa
I just rebuilt my 2002 viper motor and am only getting compression readings of approx 85-90-90. Within the 10% of each other but way low. I used new spi pistons and rings, all cylinder measurement came out good. It idles good and runs fine when on a jack stand. Can't test under load, no snow. I tested with 2 different guages both read low.
The compression gauges where the ones with over a foot and a half of hose on them. Is this why I am getting a low reading? Or is something wrong?
Tested WOT, 5-10 pulls.

Any suggestions

Thanks
 

With that low of reading it should be easy to pull over.............?You know like one hand it without a struggle.

My rebuilt 98 with spi pistons is hard to pull over compared to the other 2 srxs i own.It takes 2 hands and 1 foot on the boards when cold out.

You should check the sqwish and try spraying starter fuid around the crankcase seals when running.



.
 
Not that easy to pull over. Takes two hands feet on the floor when cold.

Squish is at .065, head gasket mod done used only one layer

I just replaced the crank seals when rebuilt, unless installed them wrong if possible?

Will check with starting fluid
 
x3 on rings not seated in yet. after a good ride, re-check it and i bet it will be over 110lb on the higher compression cylinders.
 
Make sure you run an oil that is not pure synthetic during the break in. I ran amsoil on one re-ring job and I never got a real good seal. I did a re-ring again last season and happened to go back to Yamalube and my ring seal was WAY better.
 
I run Klotz TC-W3 rormally and I'm coming up on a break in also. I'm looking for a good break-in oil. Any suggestions in addition to yamalube?
 
I was a little freaked when I bought my Viper that compression was low on PTO cylinder...then I read the specs and stock PTO is 24cc chamber vs 21cc on center and Mag...bought the Opticool gasket to compensate for small size/high heat in mag and center cylinder.
 
you want to run pure dino oil for breaking in the motor or at least one tank of oil. just drain it out and save it to add when your oil is down in the tank after 2-3 tanks of gas.

the spi's my brother has in his viper seem to be doing well. have run them 2 seasons so far and everything looks to be good.
 
Maim,
Would you run yamalube 10W-40 which is pure mineral oil for break in?
 
for breakin i would just go with a decent oil like shell or esso as it is only for breakin and you do not need top quality.

newbee are you breaking in a 4 stroke? if so what i said would be fine for a first oil change.
 
Maim, No it's a viper engine. And I know it sounds like an odd question but I guess what led me to ask it was that when I look at the standard 2 stroke oil providers like Yamalube or Klotz I haven't seen many straight 2 stroke mineral oil options. I'll look at the ones you mentioned. Thanks for the input, I appreciate it for sure.
 
ok i will clear what i said up a little. dino is slang for any non synthetic oil. as was mentioned above, synthetic is wayy too slipery to allow the rings to seat in properly for good compression.
 
Ok Maim,
I decided to go with Castrol 2T snowmobile oil. I believe it's staight mineral oil and hopefully I'll have a good break in. Then it will be back to Klotz tc-w3. Thanks for clearing that up for me.
 
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