Hardcore Sledder banner
1 - 20 of 29 Posts

·
Premium Member
Joined
·
3,411 Posts
Discussion Starter · #1 ·
wondering how much compression a healthy F7 engine should have?

tested mine today and have 125 PSI in each hole (both plugs out, throttle open, pulled like 8 times).
 

·
Premium Member
Joined
·
2,611 Posts
wondering how much compression a healthy F7 engine should have?

tested mine today and have 125 PSI in each hole (both plugs out, throttle open, pulled like 8 times).[/b]
thats pretty low....should be at least 140 by 4 pulls
 

·
Premium Member
Joined
·
3,411 Posts
Discussion Starter · #6 ·
anybody make a rings/gaskets top end kit?
i'll do pistons if i have to, but on a budget.
 

·
Registered
Joined
·
8,475 Posts
anybody make a rings/gaskets top end kit?
i'll do pistons if i have to, but on a budget.[/b]
Maybe you can cast those in your backyard out of recycled Polaris Storm pistons and save some money...sorry just had to throw that in Rippy. LOL
 

·
Premium Member
Joined
·
3,411 Posts
Discussion Starter · #8 ·
putting Poo parts in it would be like getting a kidney transplant from someone with the clap.
 

·
Registered
Joined
·
3,403 Posts
wondering how much compression a healthy F7 engine should have?

tested mine today and have 125 PSI in each hole (both plugs out, throttle open, pulled like 8 times).[/b]

unless you have a baseline (your sled originally read 140) with the gauge you are using 125 is not necessarily low, gauges will read different. try your gauge on a similar sled or try another gauge on yours.
 
G

·
wondering how much compression a healthy F7 engine should have?

tested mine today and have 125 PSI in each hole (both plugs out, throttle open, pulled like 8 times).[/b]

theres no way.......how many miles ya got.....not many it looks like.....my 04 has 8,000 miles and runnin strong.....no rebuild yet.......that seems otay to me.....i think if it falls below 110 then it needs rebuilt.....look up the specs....buy a new gauge....not one ya had for 20 years
 

·
Registered
Joined
·
2,179 Posts
Yep...could very well be the gauge. My dealer did a check for me when I had about 1000 miles on it. Both sides tested 120 with his gauge. He compared it with 2 other relatively new sleds and they were each within 2-3 lbs. Unless you had a baseline reading or something else to compare it with, don't go rushing to rebuild the top end.
 

·
Registered
Joined
·
336 Posts
Are you holding throttle wide open and good 10 cranks. The most important thing is that both sides are within 10%. (120 psi x 10% = 12psi ).
 

·
Premium Member
Joined
·
3,411 Posts
Discussion Starter · #16 ·
both sides are dead even at 125 LBS, i'm at like 125 feet above sea level, and using a pretty new Matco compression tester (not cheap, or old).
i do agree with the base line idea though.
i'll compare readings against my buddy's gauge too.
i also have a riding partner with a F7 that i can use my gauge on to compare, but his runs way better than mine. that is why i tested mine to start with.
 

·
Registered
Joined
·
1,509 Posts
Considering both cylinders are reading almost identical, AND considering you said it's only got like ~1800 miles on it???? :rolleyes: I'm sure it's probably fine!

I just had to do a top end job on my motor, with almost 6000 miles on it, and everything (other than a melted piston! :() was in excellent shape inside still, AND, until I ran it out of oil ................. :hmm: ............. it was running great :thumbsup:

You're probably fine, but double check another machine and/or use another gauge :beer_cheers:.
 

·
Registered
Joined
·
438 Posts
Check the squish of each cylinder, I'm curious to see if they are on the high side. It does happen. That is why some are stronger then others. Its possible your engine has alway had lower comprssion then others and with 1800 miles I doubt your should need new rings. I have 5000 on my sled and with the bmp high compression head I have 158, before I had 145.
 

·
Premium Member
Joined
·
3,411 Posts
Discussion Starter · #20 ·
ya, i'm not going to freak out about it, but i am kinda bummed. i know it should be a bit higher, and compression= Horsepower...i like Horsepower.
i went over to my buddies tonight with my gauge and tested it against his on his 800 Poo motor.
Both gauges are dead even for readings.

it's cool, a new topend kit is only $300 bucks, and i can do the work myself in a few hours when i get around to it.
for now i'll just keep rippin it like it is.
 
1 - 20 of 29 Posts
Top