Sticking Valve on A Sporty
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4th Gear
Joined: Apr 2010
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Sticking Valve on A Sporty
I,ve got a 2005 Sporty 1200 Roadster with about 57K on it. And It us usually stored outside under a tent. But as our temperatures come down(24 THIS AM), it is obviously harder to start. It was 40 degrees as I just started it, and it started fine,but am pretty sure that one of the valves on the rear cylinder is sticking?
And can hear it just firing on one, until it warms up, then it usually takes care of itself, and runs fine.
Anyone else ever have this problem?? And a good solution??
Thanks!
Randy
And can hear it just firing on one, until it warms up, then it usually takes care of itself, and runs fine.
Anyone else ever have this problem?? And a good solution??
Thanks!
Randy
Road Captain
Joined: Jan 2009
Posts: 566
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From: Seattle, WA
Valves don't "stick." Not without a crap-ton of other stuff wrong that would make a lot more noise than just running on one cylinder.
Have you checked to make sure that the rear cylinder is getting spark? It's much more likely that there's an issue with the coil (or somewhere else in the ignition circuit) that's preventing the rear cylinder from firing until it's warmed up.
Have you checked to make sure that the rear cylinder is getting spark? It's much more likely that there's an issue with the coil (or somewhere else in the ignition circuit) that's preventing the rear cylinder from firing until it's warmed up.
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4th Gear
Joined: Apr 2010
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Zenmervolt, I have not checked the spark problem yet, but recently removed, and cleaned up that specific plug. I said that it sounded like the exhaust valve was sticking because of the sound, and when I placed my glove over the front pipe, then the rear, there was a noticeable amount of push back between the two..as if the exhaust valve was sticking on closing, and allowing some neutral to mini vacuum action going on?
And I recently did a compression check on both cylinders, and they were both fairly equal.
But he bike was warmed up when I did the test.
And I recently did a compression check on both cylinders, and they were both fairly equal.
But he bike was warmed up when I did the test.
Outstanding HDF Member
Joined: Oct 2009
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From: Maryland near DC
I would suggest that you redo the compression test with the engine cold to find out if the valve is really sticking, I have never heard of it happening, and then go from there...more likely a different issue..I would check to make sure that the rear exhaust flange is not leaking, and for electrical spark issues (which can show up when its cold out)...if you do find that it has a sticking exhaust valve you can try squirting some ATF in the spark plug hole and turning it over a few times to disperse it around the cylinder and onto the valve and valve stem, let it sit a few hours to over night, turn over a few more times with the plugs still out and a rag over the plug hole to catch the ATF that comes out of the spark hole..reinstall the plugs and start it up outside (there will be big cloud of smoke) and go for a long ride to see if it is better..if that doesn't free it up you will need to remove the head and clean the valve and valve guide...also if the exhaust valve is sticking,, when you pull the plug and stick your finger over theplug hole and turn it over (by hand) it should not try and suck your finger or blow it off the hole very much...on the other hand these bikes are know to sometimes have bad lifters so that may be your issue..BUT I am willing to bet the issue is electrical, maybe try switching the plugs and wires and see if the issue goes to the front cylinder..
Road Captain
Joined: Jan 2009
Posts: 566
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From: Seattle, WA
Also, again, a valve cannot stick closed. If it did, it would break something in the valvetrain. For a valve to stick closed, a rocker arm would have to snap, a pushrod would have to break, or the cam would have to fail somehow. None of those would get better when the engine warmed up.
Even if the hydraulic lifter collapsed, that would not be enough for the valve to stick closed. A collapsed lifter would also clatter very noticeably until it pumped up.
The valve could potentially stick partially open if something got stuck on the valve seat, but that's not what you're talking about.
You need to check for spark, and check cold compression values. Remember, when checking compression numbers, you need to have the throttle wide open.
Stage I
Joined: May 2021
Posts: 1
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From: Okc
Sticking valve
I would suggest that you redo the compression test with the engine cold to find out if the valve is really sticking, I have never heard of it happening, and then go from there...more likely a different issue..I would check to make sure that the rear exhaust flange is not leaking, and for electrical spark issues (which can show up when its cold out)...if you do find that it has a sticking exhaust valve you can try squirting some ATF in the spark plug hole and turning it over a few times to disperse it around the cylinder and onto the valve and valve stem, let it sit a few hours to over night, turn over a few more times with the plugs still out and a rag over the plug hole to catch the ATF that comes out of the spark hole..reinstall the plugs and start it up outside (there will be big cloud of smoke) and go for a long ride to see if it is better..if that doesn't free it up you will need to remove the head and clean the valve and valve guide...also if the exhaust valve is sticking,, when you pull the plug and stick your finger over theplug hole and turn it over (by hand) it should not try and suck your finger or blow it off the hole very much...on the other hand these bikes are know to sometimes have bad lifters so that may be your issue..BUT I am willing to bet the issue is electrical, maybe try switching the plugs and wires and see if the issue goes to the front cylinder..
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