Stuck piston rings or glazed walls

cuong-nutz · March 2nd, 2013, 05:42 PM

What are the causes of stuck piston rings or glazed walls that would cause low compression? 2008 250 which sat for 2 years or so. Bike now currently has 1577 miles.

Wierd thing is bike starts and runs, doesn't have that fast get-up that I'm accustomed to and I noticed I burned through half a tank and managed 88 miles. Oil has a strong odor of gasoline.

alex.s · March 2nd, 2013, 05:45 PM

water in through the intake maybe? what does the coolant look like

Racer x · March 2nd, 2013, 07:19 PM

Carbon and rust sit on the piston and form on the cylinder walls. When you try to start it the rings scrape the rust off. The powdered rust and carbon in the ring lands mix with oil and fuel and stick the rings like glue.
I have pulled the cylinder cleaned the rings and put it together and it started right up.

bruce71198 · March 2nd, 2013, 08:40 PM

Strong odor of gasoline in the oil and the high fuel consumption lead me to believe that the bike is running extremely rich. This would also cause low compression readings due to the fuel washing down the cylinder walls. As well as the not so snappy performance. Check to make sure your vacuum petcock diaphragm hasn't ruptured allowing fuel to be drawn in through the vacuum sorce for it.

Motofool · March 2nd, 2013, 11:50 PM

Agree with above posters.

In addition:

Check that the choke's plunge is free to close completely.

Also check that the carbs don't overflow while the engine is working, or that the level of fuel inside the bowls is not higher than specifications.

If so, the valves of the floats may need replacement.

cuong-nutz · March 3rd, 2013, 11:46 AM

Quote:

Originally Posted by alex.s

water in through the intake maybe? what does the coolant look like

Coolant level is normal and no contamination seen.

Quote:

Originally Posted by Racer x

Carbon and rust sit on the piston and form on the cylinder walls. When you try to start it the rings scrape the rust off. The powdered rust and carbon in the ring lands mix with oil and fuel and stick the rings like glue.
I have pulled the cylinder cleaned the rings and put it together and it started right up.

Hope it's just this easy and no further parts are needed.

Quote:

Originally Posted by bruce71198

Strong odor of gasoline in the oil and the high fuel consumption lead me to believe that the bike is running extremely rich. This would also cause low compression readings due to the fuel washing down the cylinder walls. As well as the not so snappy performance. Check to make sure your vacuum petcock diaphragm hasn't ruptured allowing fuel to be drawn in through the vacuum sorce for it.

Stock carbs so it hasn't been jetted or shimmed. What's a Quick way to test petcock diaphragm?

Quote:

Originally Posted by Motofool

Agree with above posters.

In addition:

Check that the choke's plunge is free to close completely.

Also check that the carbs don't overflow while the engine is working, or that the level of fuel inside the bowls is not higher than specifications.

If so, the valves of the floats may need replacement.

I didn't measure the float heights when I cleaned the carbs but th valves seemed to function normal. They were not sticking.

bruce71198 · March 3rd, 2013, 02:05 PM

The fuel petcock (fuel valve on the gas tank were the gas hoses to your carbs are attached) has a small black rubber hose going to it, this is the smallest diameter hose attached to the petcock, simply remove the end at the petcock and see if there is any raw fuel present. Let it sit for a while and see if a drip of fuel forms at the petcock. If any liquid fuel is present the rubber diaphragm is shot and needs replacing.

cuong-nutz · March 3rd, 2013, 04:04 PM

Okay. Well if that's the case, no leaky diaphragm. The gas tank has been sitting on the ground and no fuel has been leaking out.

bruce71198 · March 4th, 2013, 04:33 AM

Ok, ruled that out. Now you need to find out how the extra fuel is making its way to the crank case. Do you by any chance leave the petcock in the PRI position when the bikes not running ?

Motofool · March 4th, 2013, 07:37 AM

Quote:

Originally Posted by cuong-nutz

.........I didn't measure the float heights when I cleaned the carbs but the valves seemed to function normal. They were not sticking.

You could have altered the heights by pressing on the floats; I would check it.

Quote:

Originally Posted by bruce71198

Ok, ruled that out. Now you need to find out how the extra fuel is making its way to the crank case.......

If the rings are not working properly, compression should be low and enough raw mix should leak down into the crankcase during each compression stroke.

A compression and leak test would be advisable as well.
If positive results for leaking rings, then follow post #3.

cuong-nutz · March 4th, 2013, 10:34 AM

Quote:

Originally Posted by bruce71198

Ok, ruled that out. Now you need to find out how the extra fuel is making its way to the crank case. Do you by any chance leave the petcock in the PRI position when the bikes not running ?

Nope didn't.

Quote:

Originally Posted by Motofool

You could have altered the heights by pressing on the floats; I would check it.

If the rings are not working properly, compression should be low and enough raw mix should leak down into the crankcase during each compression stroke.

A compression and leak test would be advisable as well.
If positive results for leaking rings, then follow post #3.

I guess I'll start tearing down the motor when I get some free time. I verified rings weren't sealing with a wet compression test.

bruce71198 · March 4th, 2013, 11:57 AM

How low is the compression ? Engine warm or cold ? Throttle held wide open, although not always effective with CV carbs ? Also how many miles do you usually get out of half of a tank ?

cuong-nutz · March 4th, 2013, 02:32 PM

I think compression built up to 90psi. Cold engine. Throttle held open. I think I use to get like 175 on half a tank?

Racer x · March 4th, 2013, 02:37 PM

Anything below 125 and it will have trouble. 90 wont run. should be 150-200 or something is wrong.
I am trying to fix that problem now on a friends bike.

bruce71198 · March 5th, 2013, 04:26 AM

Seems odd, with so few miles, looks like its tear down time. Let us know what turns up.

March 2nd, 2013, 05:42 PM	#1
cuong-nutz RIP Alex Name: Cuong Location: Houston, TX Join Date: Apr 2011 Motorcycle(s): '10 250r, '09 265r Posts: A lot. Blog Entries: 2	Stuck piston rings or glazed walls What are the causes of stuck piston rings or glazed walls that would cause low compression? 2008 250 which sat for 2 years or so. Bike now currently has 1577 miles. Wierd thing is bike starts and runs, doesn't have that fast get-up that I'm accustomed to and I noticed I burned through half a tank and managed 88 miles. Oil has a strong odor of gasoline. __________________________________________________ HalfFast Racing Team Serving Greater Houston Area Riders:WFO Riders MotoHouston HPC CMRA Ride Smart Fastline Lone Star Track Days

March 2nd, 2013, 05:45 PM	#2
alex.s wat Name: wat Location: tustin/long beach Join Date: Sep 2009 Motorcycle(s): wat Posts: Too much. Blog Entries: 5 MOTM - Oct '12, Feb '14	water in through the intake maybe? what does the coolant look like __________________________________________________

March 2nd, 2013, 07:19 PM	#3
Racer x ninjette.org certified postwhore Name: Eric Location: Iowa City Join Date: May 2009 Motorcycle(s): 2008 Kawmeracchi 350 2010 Project X Posts: A lot. Blog Entries: 54 MOTM - Sep '18, Feb '16	Carbon and rust sit on the piston and form on the cylinder walls. When you try to start it the rings scrape the rust off. The powdered rust and carbon in the ring lands mix with oil and fuel and stick the rings like glue. I have pulled the cylinder cleaned the rings and put it together and it started right up. __________________________________________________ Top speed 123.369mph. Ohio mile Worlds fastest 250 ninja
	2 out of 2 members found this post helpful.

March 2nd, 2013, 08:40 PM	#4
bruce71198 ninjette.org sage Name: bruce Location: northern illinois Join Date: Jan 2012 Motorcycle(s): Race bikes:08 Ninja 250,11 R6,16 ZX6,SV650.3 HD-1947,2-2003,2010. 1946 Indian and a lot of dirt bikes.2 Posts: 999	Strong odor of gasoline in the oil and the high fuel consumption lead me to believe that the bike is running extremely rich. This would also cause low compression readings due to the fuel washing down the cylinder walls. As well as the not so snappy performance. Check to make sure your vacuum petcock diaphragm hasn't ruptured allowing fuel to be drawn in through the vacuum sorce for it.
	1 out of 1 members found this post helpful.

March 2nd, 2013, 11:50 PM	#5
Motofool Daily Ninjette rider Name: Hernan Location: Florida Join Date: Mar 2011 Motorcycle(s): 2007 Ninja 250 Posts: A lot. MOTY - 2016, MOTM - Dec '12, Jan '14, Jan '15, May '16	Agree with above posters. In addition: Check that the choke's plunge is free to close completely. Also check that the carbs don't overflow while the engine is working, or that the level of fuel inside the bowls is not higher than specifications. If so, the valves of the floats may need replacement. __________________________________________________ *Motofool* *.................................Never ride faster than your guardian angel can fly* "Mankind is composed of two sorts of men — those who love and create, and those who hate and destroy. Love is the bond between men, the way to teach and the center of the world." - José Martí

March 3rd, 2013, 02:05 PM	#7
bruce71198 ninjette.org sage Name: bruce Location: northern illinois Join Date: Jan 2012 Motorcycle(s): Race bikes:08 Ninja 250,11 R6,16 ZX6,SV650.3 HD-1947,2-2003,2010. 1946 Indian and a lot of dirt bikes.2 Posts: 999	The fuel petcock (fuel valve on the gas tank were the gas hoses to your carbs are attached) has a small black rubber hose going to it, this is the smallest diameter hose attached to the petcock, simply remove the end at the petcock and see if there is any raw fuel present. Let it sit for a while and see if a drip of fuel forms at the petcock. If any liquid fuel is present the rubber diaphragm is shot and needs replacing.

March 3rd, 2013, 04:04 PM	#8
cuong-nutz RIP Alex Name: Cuong Location: Houston, TX Join Date: Apr 2011 Motorcycle(s): '10 250r, '09 265r Posts: A lot. Blog Entries: 2	Okay. Well if that's the case, no leaky diaphragm. The gas tank has been sitting on the ground and no fuel has been leaking out. __________________________________________________ HalfFast Racing Team Serving Greater Houston Area Riders:WFO Riders MotoHouston HPC CMRA Ride Smart Fastline Lone Star Track Days

March 4th, 2013, 04:33 AM	#9
bruce71198 ninjette.org sage Name: bruce Location: northern illinois Join Date: Jan 2012 Motorcycle(s): Race bikes:08 Ninja 250,11 R6,16 ZX6,SV650.3 HD-1947,2-2003,2010. 1946 Indian and a lot of dirt bikes.2 Posts: 999	Ok, ruled that out. Now you need to find out how the extra fuel is making its way to the crank case. Do you by any chance leave the petcock in the PRI position when the bikes not running ?

March 4th, 2013, 11:57 AM	#12
bruce71198 ninjette.org sage Name: bruce Location: northern illinois Join Date: Jan 2012 Motorcycle(s): Race bikes:08 Ninja 250,11 R6,16 ZX6,SV650.3 HD-1947,2-2003,2010. 1946 Indian and a lot of dirt bikes.2 Posts: 999	How low is the compression ? Engine warm or cold ? Throttle held wide open, although not always effective with CV carbs ? Also how many miles do you usually get out of half of a tank ?

March 4th, 2013, 02:32 PM	#13
cuong-nutz RIP Alex Name: Cuong Location: Houston, TX Join Date: Apr 2011 Motorcycle(s): '10 250r, '09 265r Posts: A lot. Blog Entries: 2	I think compression built up to 90psi. Cold engine. Throttle held open. I think I use to get like 175 on half a tank? __________________________________________________ HalfFast Racing Team Serving Greater Houston Area Riders:WFO Riders MotoHouston HPC CMRA Ride Smart Fastline Lone Star Track Days

March 4th, 2013, 02:37 PM	#14
Racer x ninjette.org certified postwhore Name: Eric Location: Iowa City Join Date: May 2009 Motorcycle(s): 2008 Kawmeracchi 350 2010 Project X Posts: A lot. Blog Entries: 54 MOTM - Sep '18, Feb '16	Anything below 125 and it will have trouble. 90 wont run. should be 150-200 or something is wrong. I am trying to fix that problem now on a friends bike. __________________________________________________ Top speed 123.369mph. Ohio mile Worlds fastest 250 ninja
	1 out of 1 members found this post helpful.

March 5th, 2013, 04:26 AM	#15
bruce71198 ninjette.org sage Name: bruce Location: northern illinois Join Date: Jan 2012 Motorcycle(s): Race bikes:08 Ninja 250,11 R6,16 ZX6,SV650.3 HD-1947,2-2003,2010. 1946 Indian and a lot of dirt bikes.2 Posts: 999	Seems odd, with so few miles, looks like its tear down time. Let us know what turns up.

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