Leak Down Test Benefits

[marcair]

Oil burner. 500 miles - 1 qt of 10-40 syn. No oil in intake. Warm engine Compression test dry - 149 -151. Wet - 171 - 175.
note that engine is setup as a low compression arrangement for increased low end torque.

Question: although I'm focused on the rings / cylinder walls, would a leak down test identify another cause.

 

[marcair]

Also no external leaks, no burning at startup and no visible smoke while driving. Tailpipe internal surface is blackened and sooty.

 

[jermzfree]

How many miles? Are you checking the oil level on level ground each time and same engine temp too?

 

[marcair]

Lately been checking level daily. 3k since rebuild. Builder stated 80psi after assembly to seat rings.

Today's test: engine warm no smoke at idle. Quick rev to 8k and hold for 5 sec: split second of black smoke then clean. during rev down to idle blue smoke for a few seconds.

I use the Suzuki synthetic 10x40. Would switching to 15x50 prolong the inevitable ring job?

 

[mabupa]

Oil burner. 500 miles - 1 qt of 10-40 syn. No oil in intake. Warm engine Compression test dry - 149 -151. Wet - 171 - 175.
note that engine is setup as a low compression arrangement for increased low end torque.

Question: although I'm focused on the rings / cylinder walls, would a leak down test identify another cause.

There is a lot of members here that are good with engines and can give you some good tips. How about listing some info/history about the bike. Year, miles, any engine mods, drag race, etc?
Good luck!

 

[Sputter]

If you are getting blue smoke on deceleration it usually indicates oil getting past valve guides. A leak down will not show a bad valve guide or a bad valve seal. Also lower compression will hurt torque(bottom end power). Good luck!

 

[jermzfree]

Oil burner. 500 miles - 1 qt of 10-40 syn. No oil in intake. Warm engine Compression test dry - 149 -151. Wet - 171 - 175.
note that engine is setup as a low compression arrangement for increased low end torque.

Question: although I'm focused on the rings / cylinder walls, would a leak down test identify another cause.

The leak down will tell you the condition of your cylinder walls/rings very well. 1% leakage great. > 10% not good. Maybe eliminate that first. What is your altitude? 150 psi isn't necessarily bad compression. Temperature and altitude effect compression, and the manufacturers compression of 180+ is at sea level I believe. And if the compression tester you are using has the little one way valve at the end of the rubber hose near the gauge, your reading will be low by ~15psi.

 

[David Offor]

A leakdown test will also give you an indication of your valve condition and how well they are seating, listen at the intake side (preferably with throttle body off) to hear leakage on inlet valves and opposite of head (with exhaust dissconnected) for exhaust valve leakage, it showed up a problem on my bike, my valve guides had excessive sideways movement, which was not allowing the valves to return 'squarely' to make a good seal, blue smoke is definitely oil getting into the bores, probably valve stem oil seals, as previously mentioned.

 

[Edward Smith]

The leak down will tell you the condition of your cylinder walls/rings very well. 1% leakage great. > 10% not good. Maybe eliminate that first. What is your altitude? 150 psi isn't necessarily bad compression. Temperature and altitude effect compression, and the manufacturers compression of 180+ is at sea level I believe. And if the compression tester you are using has the little one way valve at the end of the rubber hose near the gauge, your reading will be low by ~15psi.

The leak down will tell you the condition of your cylinder walls/rings very well. 1% leakage great. > 10% not good. Maybe eliminate that first. What is your altitude? 150 psi isn't necessarily bad compression. Temperature and altitude effect compression, and the manufacturers compression of 180+ is at sea level I believe. And if the compression tester you are using has the little one way valve at the end of the rubber hose near the gauge, your reading will be low by ~15psi.

Hey jermzfree could you possibly give me a better breakdown of what u mean? My 06 recently tested low on compression as well ; c1=

 

[jermzfree]

Hey jermzfree could you possibly give me a better breakdown of what u mean? My 06 recently tested low on compression as well ; c1=

Compression testers do vary. If your tester is a harbor freight like mine then your reading will be low ~15psi. The one way relief valve is located near the gauge at the end of the tubing. The expansion of the tubing during the compression test will cause this loss.

Here is a good link http://www.arboristsite.com/community/threads/altitude-and-compression-testing.82993/ What is your compression for each cylinder after adjusting for altitude?

 

[Edward Smith]

I'm not sure but my brother n law done it with a harbor freight tester. #1= 175, 2=165, 3&4=180. One machanic said it wasn't low enough to need a rebuild to search for other problems aboard within gas coils etc. And my brother n law saying it needs rebuilding because he said it sounds like it's running on 3 cylinders. I'm at a loss and in desperate of it not needing a rebuild since I just got the bike. Any help would be greatly appreciated. Thanks in advance.

 

[jermzfree]

I'm not sure but my brother n law done it with a harbor freight tester. #1= 175, 2=165, 3&4=180. One machanic said it wasn't low enough to need a rebuild to search for other problems aboard within gas coils etc. And my brother n law saying it needs rebuilding because he said it sounds like it's running on 3 cylinders. I'm at a loss and in desperate of it not needing a rebuild since I just got the bike. Any help would be greatly appreciated. Thanks in advance.

Might have an issue with number 2. A leak down test would tell you a lot. Don't yank the motor yet. Just for reference my stock 04 reads 160 psi in all cylinders. Means nothing to me because it makes 157 hp, and on a cold motor the leak down test is 1% in all 4 cylinders. If you have not done a leak down test before here is a neat trick to find tdc on the compression stroke.

 

[Edward Smith]

Found problem dude had my #1&#2 spark plug connectors reversed

 

[David Offor]

Found problem dude had my #1&#2 spark plug connectors reversed

Oooops

 

[Edward Smith]

Ikr n my brother n law working on it kept telling me I needed my motor rebuilt which kept leading to back n forth disagreements because I want trying to hear that since I've only ride the bike once and it wasn't pulling. Going to put it back together and hope that's all the problem was.

 

[shade]

Rule #1 IN LAWS DONT KNOW poop

 

[Edward Smith]

No I have a clutch problem!!! Can't get it to work out get it to bleed!!! Hello help lol

 

[Edward Smith]

Now I have a clutch problem!!! Can't get it to work can't get it to bleed!!! Hello help lol