Author Topic: valve seal install  (Read 1186 times)

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Offline Aaron Richard

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valve seal install
« on: July 13, 2009, 11:58:52 AM »
Is there a way to change these without taking the head off? If not, does the cam chain have to be broken apart to lift the head off? Haven't dug into the motor this deep yet, An want to make it as painless as possible  ::)

Offline Bodain

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Re: valve seal install
« Reply #1 on: July 13, 2009, 12:43:47 PM »
Hmmm. To change a valve seal. You have to remove keepers, and valve spring. Even if this could be accomplished with head on. The valve would drop onto the pistons. This would be more grief than you can imagine. Take the head off and use a valve spring compression tools.

The cam chain just comes off the cam, without breaking it.
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Offline Aaron Richard

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Re: valve seal install
« Reply #2 on: July 13, 2009, 12:46:59 PM »
ok sounds good. My main thing was I diddn't have to break the chain. If I can just slide it off, I'll take the head off.
Thanks

Offline MCRider

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Re: valve seal install
« Reply #3 on: July 13, 2009, 12:47:22 PM »
Is there a way to change these without taking the head off? If not, does the cam chain have to be broken apart to lift the head off? Haven't dug into the motor this deep yet, An want to make it as painless as possible  ::)
I have changed mine on my CB750 motor in the past, along with the valve springs. I took the hi perf ones out and replaced with stockers. Motor in frame (rail removal kit), head on,  used an external valve spring compressor common for cars.

Just set each cylinder at top dead center as you do them, one at a time. The valve will only drop a skosh til it hits the piston, and the rest of the job was easy.
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1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."

Offline Aaron Richard

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Re: valve seal install
« Reply #4 on: July 13, 2009, 01:14:04 PM »
Is there a way to change these without taking the head off? If not, does the cam chain have to be broken apart to lift the head off? Haven't dug into the motor this deep yet, An want to make it as painless as possible  ::)
I have changed mine on my CB750 motor in the past, along with the valve springs. I took the hi perf ones out and replaced with stockers. Motor in frame (rail removal kit), head on,  used an external valve spring compressor common for cars.

Just set each cylinder at top dead center as you do them, one at a time. The valve will only drop a skosh til it hits the piston, and the rest of the job was easy.


I thought that may be posible to do it that way but, didn't know if the piston went up far enough to keep the valve up. Maybe I'll try it that way first and if it doesn't work out, I'll take the head off.

Offline MCRider

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Re: valve seal install
« Reply #5 on: July 13, 2009, 01:22:14 PM »
Is there a way to change these without taking the head off? If not, does the cam chain have to be broken apart to lift the head off? Haven't dug into the motor this deep yet, An want to make it as painless as possible  ::)
I have changed mine on my CB750 motor in the past, along with the valve springs. I took the hi perf ones out and replaced with stockers. Motor in frame (rail removal kit), head on,  used an external valve spring compressor common for cars.

Just set each cylinder at top dead center as you do them, one at a time. The valve will only drop a skosh til it hits the piston, and the rest of the job was easy.


I thought that may be posible to do it that way but, didn't know if the piston went up far enough to keep the valve up. Maybe I'll try it that way first and if it doesn't work out, I'll take the head off.
It will only drop 1/8" or so, hate disturbing an otherwise OK head gasket, assuming yours isn't leaking.  But if you're up to it, pull the head and lap the valves in. Freshen it up a bit. 
Ride Safe:
Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."