valve sticking???
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valve sticking???
how do you know if a valve is sticking....sometimes while kicking it feels like somethings holding it back...from kicking over...dose not start
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Re: valve sticking???
Are you pretty sure it's not the kicker assembly giving you the problem?
Next time it happens, pull the clutch in and see if it's still locked up. If it is, put the bike in gear and rock it back and forth, then put it back in neutral and try again. A peek under the kicker cover may be in your future. It's a pretty easy repair.
Steve
Next time it happens, pull the clutch in and see if it's still locked up. If it is, put the bike in gear and rock it back and forth, then put it back in neutral and try again. A peek under the kicker cover may be in your future. It's a pretty easy repair.
Steve
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Re: valve sticking???
Slick58pandhead!
A sticking valve goes:
tictictictictictictactactactacktackclackclackwhangbangbangboom. ....Cotten
A sticking valve goes:
tictictictictictictactactactacktackclackclackwhangbangbangboom. ....Cotten
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Last edited by Cotten on Tue Jul 10, 2012 2:04 pm, edited 3 times in total.
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Re: valve sticking???
slick
You may be on the right track but its not the valve that sticks, it is the lifter that collapses. If the lifters do not pump up and they fail to open the valves after a few kicks the compression will build up in the cylinder and make it feel like the motor is locked tight. The original pans with the hydraulic lifters built into the push rods were famous for that, my 49 drove me nuts until I pulled them all out and replaced them with solid push rods.
If you have hydraulic lifters I would start by looking at them........
mike
You may be on the right track but its not the valve that sticks, it is the lifter that collapses. If the lifters do not pump up and they fail to open the valves after a few kicks the compression will build up in the cylinder and make it feel like the motor is locked tight. The original pans with the hydraulic lifters built into the push rods were famous for that, my 49 drove me nuts until I pulled them all out and replaced them with solid push rods.
If you have hydraulic lifters I would start by looking at them........
mike
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Re: valve sticking???
flatheadsix.....sorry but i just started messing around with my 58 the other day....and what do you know my rear cylinder lifters were collapsed....a friend of mine had two spares(lifters)...and she's up and running....i ordered solids...cause there's still a little resistance maybe in the front cylinder....i thank you very much...
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Re: valve sticking???
thanks your it was driving me nutty tooFlatHeadSix wrote:slick
You may be on the right track but its not the valve that sticks, it is the lifter that collapses. If the lifters do not pump up and they fail to open the valves after a few kicks the compression will build up in the cylinder and make it feel like the motor is locked tight. The original pans with the hydraulic lifters built into the push rods were famous for that, my 49 drove me nuts until I pulled them all out and replaced them with solid push rods.
If you have hydraulic lifters I would start by looking at them........
mike
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Re: valve sticking???
C'mon Kitabel!kitabel wrote:after a few kicks the compression will build up in the cylinder
Not possible.
Think about it.
A collapsed lifter only allows an exhaust valve to open slightly, and very late; late enough that the compression rebounds the kicker.
....Cotten
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Re: valve sticking???
now when i change over to solids...is the adjustment the same on the push rods....very little resistance when spinning them
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Re: valve sticking???
I'm not speaking from experience, because I never had a valve stick like that, but if there is a compressed mixture in the cylinder, something greater than atmospheric pressure due to the exhaust valve failing to allow it all to escape, when the intake opens wouldn't that positive pressure, being greater than atmospheric pressure, escape through the now open intake valve? The piston is not a pump, the cylinder volume can only be filled at whatever the pressure is at that altitude, if the pressure in the cylinder is greater than one atmosphere when the intake opens, I don't think you could increase it without a supercharger. I'm just asking, please correct me if i'm wrong. Can you kick it fast enough to overcome the speed at which the mixture escapes? Could messed up valves and venting cause pressure to build in the crankcase?Cotten wrote:C'mon Kitabel!kitabel wrote:after a few kicks the compression will build up in the cylinder
Not possible.
Think about it.
A collapsed lifter only allows an exhaust valve to open slightly, and very late; late enough that the compression rebounds the kicker.
....Cotten
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Re: valve sticking???
Scrap!Scrap wrote:I'm not speaking from experience, because I never had a valve stick like that, but if there is a compressed mixture in the cylinder, something greater than atmospheric pressure due to the exhaust valve failing to allow it all to escape, when the intake opens wouldn't that positive pressure, being greater than atmospheric pressure, escape through the now open intake valve? The piston is not a pump, the cylinder volume can only be filled at whatever the pressure is at that altitude, if the pressure in the cylinder is greater than one atmosphere when the intake opens, I don't think you could increase it without a supercharger. I'm just asking, please correct me if i'm wrong. Can you kick it fast enough to overcome the speed at which the mixture escapes? Could messed up valves and venting cause pressure to build in the crankcase?Cotten wrote:C'mon Kitabel!kitabel wrote:after a few kicks the compression will build up in the cylinder
Not possible.
Think about it.
A collapsed lifter only allows an exhaust valve to open slightly, and very late; late enough that the compression rebounds the kicker.
....Cotten
It is a four-stroke motor, and the intake only opens upon the first stroke.
....Cotten
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Re: valve sticking???
slick58pandhead!slick58pandhead wrote:now when i change over to solids...is the adjustment the same on the push rods....very little resistance when spinning them
Only with steel pushrods.
Aluminum rods must be quite stiff.
...Cotten
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Re: valve sticking???
thanks..Cotten wrote:slick58pandhead!slick58pandhead wrote:now when i change over to solids...is the adjustment the same on the push rods....very little resistance when spinning them
Only with steel pushrods.
Aluminum rods must be quite stiff.
...Cotten
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Re: valve sticking???
New to this discussion but my recently built '52 Pan with hyd pushrods has been great. Easy to start and it's smooth and quiet. And my engine builder has over 10k miles on them with no issues. I do find it hard to believe that the MoCo would design a pushrod that, if it failed to pump up, would result in the motor being unable to kick over.