Beating a dead horse: Valve Seals
Road Warrior
Joined: Dec 2008
Posts: 1,639
Likes: 2
From: Australia
I'm using the search feature because I think I'm having a problem with an intake valve seal. Here's a question I'm trying to answer.
If an intake valve doesn't seal as the motor goes into the compression stroke, would that push enough air back through the valve where I could hear it via the air cleaner?
If an intake valve doesn't seal as the motor goes into the compression stroke, would that push enough air back through the valve where I could hear it via the air cleaner?
Elite HDF Member
Joined: Aug 2007
Posts: 4,265
Likes: 99
From: Northern VA
The reason I ask is because my motor isn't running like it used to. It has a hiccup and when it does, I can hear a pffft through the air cleaner. It's very sporadic and not throwing any codes, so I took it in to the dealer. They replaced the plug wires and said it's fixed. But it isn't. I'm looking for other items that could cause the problem.
Road Warrior
Joined: Dec 2008
Posts: 1,639
Likes: 2
From: Australia
But I don't own one of those...
The reason I ask is because my motor isn't running like it used to. It has a hiccup and when it does, I can hear a pffft through the air cleaner. It's very sporadic and not throwing any codes, so I took it in to the dealer. They replaced the plug wires and said it's fixed. But it isn't. I'm looking for other items that could cause the problem.
The reason I ask is because my motor isn't running like it used to. It has a hiccup and when it does, I can hear a pffft through the air cleaner. It's very sporadic and not throwing any codes, so I took it in to the dealer. They replaced the plug wires and said it's fixed. But it isn't. I'm looking for other items that could cause the problem.
They arent expensive. I bought mine for about $30 aussie, so you should be able to get one over there for $15 at pep boys or somesuch. Its the only reliable way to test the top and or bottom end.
I would say if she is coughing thru the cleaner infrequently it isnt a valve problem. A valve not seating could be caused by broken spring, bent valve etc etc, all of these things are permanent and would be there every revolution not every now and then.
My 97 would cough thru the air cleaner when she was running lean and I got a batch of bad fuel, I would wind the idle screw out 1/8 turn and she would stop. you might just have bad fuel....
I would be looking elsewhere, I doubt there is anything fundamentally wrong with the motor. Compression tester would put it beyond doubt.
Road Warrior
Joined: Jun 2008
Posts: 1,437
Likes: 80
From: currently an Okie
Seals
I'm using the search feature because I think I'm having a problem with an intake valve seal. Here's a question I'm trying to answer.
If an intake valve doesn't seal as the motor goes into the compression stroke, would that push enough air back through the valve where I could hear it via the air cleaner?
If an intake valve doesn't seal as the motor goes into the compression stroke, would that push enough air back through the valve where I could hear it via the air cleaner?
I can't imagine you could hear it at all unless you have practically no compression.
Randy
Stellar HDF Member
Joined: Mar 2007
Posts: 2,034
Likes: 45
From: Michigan
when checking compression if its low add a couple drops of oil into the cylinder then check again. If it comes up you have a ring problem if it pretty much stays the same then its a valve problem. But a compression check wont help with bad seals . It just cant tell .. Also compression should be checked with the throttle wide open.. What I dont understand is why you dont take your bike back with fouled plugs and then hammer on the service department!. If they pull the plugs they will see they are junk.
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
7 Times Harley-Davidson Chucked Tradition Out the Window
Verdad Gallardo
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
Seasoned HDF Member
Joined: Apr 2006
Posts: 10,675
Likes: 95
From: Billings,Mt.
He has to get past the bone headed service writer first!
Elite HDF Member
Joined: Aug 2007
Posts: 4,265
Likes: 99
From: Northern VA
That must be for the OP as my plugs are fine. And from info on this thread - my valve seals are also fine.