compression

[alifk69]

what does it mean by 'low compression' in bikes? and how to fix it?

[yinghai]

change piston ring.. solve everything..

[garfieldrox]

Maybe piston seize? Get it check asap. Cuz my wan happen yesterday~

 

Low Compression:- Can't start, no power...

[MS]

http://i115.photobucket.com/albums/n298/arakyo/compressiontest.jpg

 

I think your 'low compression' refers to this. This was a compression test for a 6zyl engine. You see #1 zyl failed the test being unable to generate enough pressure. #7 is a repetition of #1 to confirm the test.

 

Zyl #1 = 16bar

Zyl #2 = 25bar

Zyl #3 = 24bar

Zyl #4 = 24bar

Zyl #5 = 24bar

Zyl #6 = 24bar

 

Zyl #7 is #1 = 16.5bar

Note: To pass the test, the specs for this engine was 20bar.

 

So the piston rings and liners for this engine zyl#1 was replaced.

 

The piston rings are not able to seal off the combustion chamber to generate the require pressure when your piston moves up. This can impair your combustibility and lead to engine stall eventually. Your fuel will also leak into your crankcase at an unhealthy rate on the long run.

[garfieldrox]

Gd explain! Thank. As the same time, will the block b damage?

[MS]

Gd explain! Thank. As the same time, will the block b damage?

 

There is a chance. You can always measure the diameter and roundness of the combustion chamber and see if it is up to specifications. If it is then I guess it should be OK.

 

Engines don't lose compression for no reason. It's mostly due to age, extreme use, gasket cracked which created a route for the coolant circuitry to extend to the combustion chamber, funny run in methods that do not adhere to factory recommendations, wrong fuel ie. pumping in RON92 when you are supposed to use a minimum of RON95, wrong 2T for 2 strokers, wrong EO for 4 strokers which mean many other things will also fail apart from loss of compression pressure, etc etc...

[alifk69]

coolness... thanks for the info guys..

[Phang]

A warped cylinder head, leaky head gasket, leaky valves/seats could be the reason of a low cylinder compression reading too.

 

p/s: MS, was that a 6zyl diesel engine?

[MS]

A warped cylinder head, leaky head gasket, leaky valves/seats could be the reason of a low cylinder compression reading too.

 

p/s: MS, was that a 6zyl diesel engine?

 

haha!! Spot on correct.

[WawanAprilia]

Low compression has many causes -Lack of oil causing the rings to be overworked,old and weak piston rings,crack or opening in the head,cracked cylinder,faulty valve, worn out cyclinder ,blown head gasket,worn valve spring,wornout camshaft or rocker arm .. Very the confusin also .. haha

[lwfc]

any shop to go if want to check compression?

[garfieldrox]

Mostly shop have the device to check for the compression. although i onli saw one time the mech is using.

[mepkoh]

any shop to go if want to check compression?

 

diy..remove plug...stuff hole with rag and hold with thumb...

start engine...

if thumb cannot hold rag in place..then ok...if not seek pro advice

[lwfc]

Mostly shop have the device to check for the compression. although i onli saw one time the mech is using.

 

any shop to intro.

 

just wanna check the bar pressure

 

diy..remove plug...stuff hole with rag and hold with thumb...

start engine...

if thumb cannot hold rag in place..then ok...if not seek pro advice

 

i'm pretty sure there's compression. but wanna check the exact bar pressure whether up to paper spec anot

[garfieldrox]

Ah meng got. Saw the gauge... whahaha~

[lwfc]

ok.. maybe i go there next week. maybe can catch glimpse of pink skipper

[yinghai]

worn or dirty engine oil can reduce compression after time... usually the case is gasket leaking, spark plug thread gone, piston ring worn, shim worn, intake exhaust valve worn sometimes improper installation of timing chain/belt/gears..