SXR Compression help ?

Location
ohio
I checked the compression on my 03 SXR and the back is 150 and the front is 125. I'm installing an ADA girdled head this weekend and wondered if i should just replace rings or pistons and rings ? Can these cylinders be bored or are they plated like some dirtbike cylinders that can't be bored and need re-sleeved ? Let me know what you think - Thanks
 
I checked the compression on my 03 SXR and the back is 150 and the front is 125. I'm installing an ADA girdled head this weekend and wondered if i should just replace rings or pistons and rings ? Can these cylinders be bored or are they plated like some dirtbike cylinders that can't be bored and need re-sleeved ? Let me know what you think - Thanks

You can try and hone and re-ring the piston..If the compression doesnt come up then you will need to bore.
Any idea of what caused the loss in compression?
oil - water - ??
 

djkorn1

kidkornfilms
Site Supporter
Location
Cleveland Ohio
I would just say hell with it and throw a top end in it. Get it bored and order a kit from Wiseco. If it's a 2003, it is overdue.
 
A 2003 overdue? HA! My rule of thumb w/ 2 smokes is run em till they go! 25 LBS low on a cylinder will still run well, but it's out of spec for sure (10% on 150 is 15 LBS acceptable difference). I have owned/run 1990 SJ's w/ original motors, and dead on compression - just depends. I would pull the top end this winter, you may have some scoring on that 1 cylinder, but it's hard to tell. Only one way to find out!
 

tor*p*do

Squarenose FTW
Site Supporter
Location
NW NC
x2 what Kurt said
my '92 750sx is on original bore, rings, etc
Cylinders still 135 - 140 and equal
I will keep on running it with a 16 year old top end
until it quits:friday:
 
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THRUST

ThrustInnovations.com
ok so you let it go and it ends up costing alot more than rings . like crank cases two new pistons and a sleeve . do the hone and rings . if it is a new engine a few months old run the ski then double and triple check your compression (maybe you didnt get the gauge on tight )
 

tor*p*do

Squarenose FTW
Site Supporter
Location
NW NC
ok so you let it go . . . .

Not what Kurt and I are saying.
25 psi difference, yes you need to take a look at the top end and fix it.
we cordially disagree with DJ saying a 2003 is overdue for a top end
based on age alone
 
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