2004 Eton Viper 90 - Less Top end power after oil injection removal - Page 2 - ATVConnection.com ATV Enthusiast Community

JPNFooter · #11 (**permalink**) 02-25-2009, 08:44 PM

Sorry to butt in. LT80 you mention doing a compression test with the throttle wide open. How much of a difference does this make? I tested my kids Viper 70 without the throttle open and got 92 PSI. I was planning to replace the top end but want to make sure the compression reading is not off.
Thanks

GMoney69 · #12 (**permalink**) 02-25-2009, 10:06 PM

JP that number sounds pretty good. Why are you considering rebuilding the top end. My 90 that runs great is pushing 90 give or take from what I can tell with the crappy press in gauge I was using

JPNFooter · #13 (**permalink**) 02-26-2009, 05:57 AM

Gmoney, I had seen several post where people were getting 120 PSI. The bike just doesn't have the power that it used to. There is one other small contributing factor. There is a good chance that it has been run a substantial amount without oil. A couple weeks ago I found that the bracket where the cable connects to teh oil pump was broken. I think this happened a while ago explaining the oil spots on my garage floor. Not good on a top end from what I hear. DUH. Let me know what you think, I am all ears at this point.

LT80 · #14 (**permalink**) 02-27-2009, 09:09 AM

<div class="FTQUOTE"><begin quote>Originally posted by: JPNFooter

Sorry to butt in. LT80 you mention doing a compression test with the throttle wide open. How much of a difference does this make? I tested my kids Viper 70 without the throttle open and got 92 PSI. I was planning to replace the top end but want to make sure the compression reading is not off.

Thanks</end quote></div>

I was told to hold it open and never did it w/o being open.
I really doubt it makes a giant difference tho.

TLC · #15 (**permalink**) 02-27-2009, 09:51 AM

When you disconnected the oil injection,how did you know what to mix you gas/oil at? I just diconected a Artic Cat 440 Jag FC oil injection system and was suprised the mix ration for that motor was 20:1.

We were going to mix it at the standard 50:1 before we looked into it, that would of been a short motor life. LOL

GMoney69 · #16 (**permalink**) 10-23-2009, 07:56 PM

I hate to see incomplete threads so I figured I would close the loop although the post is dated. I shimmed 3 small washers under the jet needle to raise it up more. Problem fixed and runs like new with plenty of power at 90psi. The 05 has no part number on the needle or the slide. The 04 does. They looked the same to the eye but the needle on the 04 must be wider or longer. Both needle were in the last clip position (closest to the bottom). For the 05 this was enough but not for the 04. Took me a long time to figure out but problem solved. In addition, I use amsoil saber premix at 100:1 for this quad.

GMoney69 · #17 (**permalink**) 10-23-2009, 08:01 PM

sorry I also went from an 80 stock jet size to an 85

GMoney69 · #18 (**permalink**) 10-24-2009, 08:38 AM

One clarification I actually had to put 4 - #4 washers to get the needle jet high enough to let the proper amount of fuel through. To think I was only off one washer that whole time. Word of caution make sure if you try something similiar the you do not raise the needle up so much that it lifts out of the main jet and gets stuck wide open.