compression test

[budsyboo]

I have a 2005 sporster le di with the 947 motor in.Can some please tell me the compression should be.I have a cheap tester and it said 90 psi and i borrowed better one it said 124. Both jugs are the same. Both sound low if i read the other post everyone say's i should have 150 ideally. The boat has run great and it started ok this spring but i haven't had it on the water yet.I just want to be safe and not sorry.I have only owned the boat for 2 years and this is the first time i have tested it.

 

[Stevego]

150 is the ideal PSI. Anything below 130 means engine requires rebuild from what I have been reading here. One good thing at least they are both reading equally.

 

[ocod]

try again and make sure readings are the same.
150 is perfect but above 120 your fine but performance will off a little.
Anything lower than 100 I would think a re build is needed.

 

[TFWildman112]

are you holding the throttle wide open when your doing the test that makes a difference?

 

[budsyboo]

Thanks Wildman no I wasn't holding the throttle wide open. I will try that and also a new tester.

 

[Stevego]

Are you testing on a hot or cold engine? I understand that makes a difference also. I cannot recall if you are supposed to test on a hot or cold engine however??? There is a procedure somewhere here.....

 

[budsyboo]

Well i tested it with a new tester and with the throttle wide open and got 135 on both. So i hope i can get a year or two out of it before i have to do the top end.Any comments on how to prolong doing the top end?

 

[ocod]

I'm starting my 2nd year.
Just run the API-tc oil regular maintenance

 

[TFWildman112]

i wouldn't worry just check at the end of the season and if it's worse do it but if not run it till it gets down to like 120 you should be fine.